-#!/usr/bin/perl -w
-
-# mark.biggar@TrustedSysLabs.com
-# eay@mincom.com is dead (math::BigInteger)
-# see: http://www.cypherspace.org/~adam/rsa/pureperl.html (contacted c. adam
-# on 2000/11/13 - but email is dead
-
-# todo:
-# - fully remove funky $# stuff (maybe)
-# - use integer; vs 1e7 as base
-# - speed issues (XS? Bit::Vector?)
-# - split out actual math code to Math::BigNumber
+package Math::BigInt;
-# Qs: what exactly happens on numify of HUGE numbers? overflow?
-# $a = -$a is much slower (making copy of $a) than $a->bneg(), hm!?
-# (copy_on_write will help there, but that is not yet implemented)
+#
+# "Mike had an infinite amount to do and a negative amount of time in which
+# to do it." - Before and After
+#
# The following hash values are used:
-# value: the internal array, base 100000
+# value: unsigned int with actual value (as a Math::BigInt::Calc or similiar)
# sign : +,-,NaN,+inf,-inf
# _a : accuracy
# _p : precision
-# _cow : copy on write: number of objects that share the data (NRY)
-# Internally the numbers are stored in an array with at least 1 element, no
-# leading zero parts (except the first) and in base 100000
+# _f : flags, used by MBF to flag parts of a float as untouchable
-# USE_MUL: due to problems on certain os (os390, posix-bc) "* 1e-5" is used
-# instead of "/ 1e5" at some places, (marked with USE_MUL). But instead of
-# using the reverse only on problematic machines, I used it everytime to avoid
-# the costly comparisations. This _should_ work everywhere. Thanx Peter Prymmer
+# Remember not to take shortcuts ala $xs = $x->{value}; $CALC->foo($xs); since
+# underlying lib might change the reference!
-package Math::BigInt;
my $class = "Math::BigInt";
+require 5.005;
-$VERSION = 1.35;
-use Exporter;
-@ISA = qw( Exporter );
-@EXPORT_OK = qw( bneg babs bcmp badd bmul bdiv bmod bnorm bsub
- bgcd blcm
- bround
- blsft brsft band bior bxor bnot bpow bnan bzero
- bacmp bstr bsstr binc bdec bint binf bfloor bceil
- is_odd is_even is_zero is_one is_nan is_inf sign
- length as_number
- trace objectify _swap
- );
-
-#@EXPORT = qw( );
-use vars qw/$rnd_mode $accuracy $precision $div_scale/;
+$VERSION = '1.77';
+
+@ISA = qw(Exporter);
+@EXPORT_OK = qw(objectify bgcd blcm);
+
+# _trap_inf and _trap_nan are internal and should never be accessed from the
+# outside
+use vars qw/$round_mode $accuracy $precision $div_scale $rnd_mode
+ $upgrade $downgrade $_trap_nan $_trap_inf/;
use strict;
# Inside overload, the first arg is always an object. If the original code had
-# it reversed (like $x = 2 * $y), then the third paramater indicates this
-# swapping. To make it work, we use a helper routine which not only reswaps the
-# params, but also makes a new object in this case. See _swap() for details,
-# especially the cases of operators with different classes.
+# it reversed (like $x = 2 * $y), then the third paramater is true.
+# In some cases (like add, $x = $x + 2 is the same as $x = 2 + $x) this makes
+# no difference, but in some cases it does.
# For overloaded ops with only one argument we simple use $_[0]->copy() to
# preserve the argument.
use overload
'=' => sub { $_[0]->copy(); },
-# '+' and '-' do not use _swap, since it is a triffle slower. If you want to
-# override _swap (if ever), then override overload of '+' and '-', too!
-# for sub it is a bit tricky to keep b: b-a => -a+b
-'-' => sub { my $c = $_[0]->copy; $_[2] ?
- $c->bneg()->badd($_[1]) :
- $c->bsub( $_[1]) },
-'+' => sub { $_[0]->copy()->badd($_[1]); },
-
# some shortcuts for speed (assumes that reversed order of arguments is routed
# to normal '+' and we thus can always modify first arg. If this is changed,
# this breaks and must be adjusted.)
'-=' => sub { $_[0]->bsub($_[1]); },
'*=' => sub { $_[0]->bmul($_[1]); },
'/=' => sub { scalar $_[0]->bdiv($_[1]); },
+'%=' => sub { $_[0]->bmod($_[1]); },
+'^=' => sub { $_[0]->bxor($_[1]); },
+'&=' => sub { $_[0]->band($_[1]); },
+'|=' => sub { $_[0]->bior($_[1]); },
+
'**=' => sub { $_[0]->bpow($_[1]); },
+'<<=' => sub { $_[0]->blsft($_[1]); },
+'>>=' => sub { $_[0]->brsft($_[1]); },
+# not supported by Perl yet
+'..' => \&_pointpoint,
+
+# we might need '==' and '!=' to get things like "NaN == NaN" right
'<=>' => sub { $_[2] ?
- $class->bcmp($_[1],$_[0]) :
- $class->bcmp($_[0],$_[1])},
-'cmp' => sub {
+ ref($_[0])->bcmp($_[1],$_[0]) :
+ $_[0]->bcmp($_[1]); },
+'cmp' => sub {
$_[2] ?
- $_[1] cmp $_[0]->bstr() :
- $_[0]->bstr() cmp $_[1] },
-
+ "$_[1]" cmp $_[0]->bstr() :
+ $_[0]->bstr() cmp "$_[1]" },
+
+# make cos()/sin()/exp() "work" with BigInt's or subclasses
+'cos' => sub { cos($_[0]->numify()) },
+'sin' => sub { sin($_[0]->numify()) },
+'exp' => sub { exp($_[0]->numify()) },
+'atan2' => sub { $_[2] ?
+ atan2($_[1],$_[0]->numify()) :
+ atan2($_[0]->numify(),$_[1]) },
+
+# are not yet overloadable
+#'hex' => sub { print "hex"; $_[0]; },
+#'oct' => sub { print "oct"; $_[0]; },
+
+'log' => sub { $_[0]->copy()->blog($_[1]); },
'int' => sub { $_[0]->copy(); },
'neg' => sub { $_[0]->copy()->bneg(); },
'abs' => sub { $_[0]->copy()->babs(); },
+'sqrt' => sub { $_[0]->copy()->bsqrt(); },
'~' => sub { $_[0]->copy()->bnot(); },
-'*' => sub { my @a = ref($_[0])->_swap(@_); $a[0]->bmul($a[1]); },
-'/' => sub { my @a = ref($_[0])->_swap(@_);scalar $a[0]->bdiv($a[1]);},
-'%' => sub { my @a = ref($_[0])->_swap(@_); $a[0]->bmod($a[1]); },
-'**' => sub { my @a = ref($_[0])->_swap(@_); $a[0]->bpow($a[1]); },
-'<<' => sub { my @a = ref($_[0])->_swap(@_); $a[0]->blsft($a[1]); },
-'>>' => sub { my @a = ref($_[0])->_swap(@_); $a[0]->brsft($a[1]); },
-
-'&' => sub { my @a = ref($_[0])->_swap(@_); $a[0]->band($a[1]); },
-'|' => sub { my @a = ref($_[0])->_swap(@_); $a[0]->bior($a[1]); },
-'^' => sub { my @a = ref($_[0])->_swap(@_); $a[0]->bxor($a[1]); },
-
-# can modify arg of ++ and --, so avoid a new-copy for speed, but don't
-# use $_[0]->_one(), it modifies $_[0] to be 1!
+# for subtract it's a bit tricky to not modify b: b-a => -a+b
+'-' => sub { my $c = $_[0]->copy; $_[2] ?
+ $c->bneg()->badd( $_[1]) :
+ $c->bsub( $_[1]) },
+'+' => sub { $_[0]->copy()->badd($_[1]); },
+'*' => sub { $_[0]->copy()->bmul($_[1]); },
+
+'/' => sub {
+ $_[2] ? ref($_[0])->new($_[1])->bdiv($_[0]) : $_[0]->copy->bdiv($_[1]);
+ },
+'%' => sub {
+ $_[2] ? ref($_[0])->new($_[1])->bmod($_[0]) : $_[0]->copy->bmod($_[1]);
+ },
+'**' => sub {
+ $_[2] ? ref($_[0])->new($_[1])->bpow($_[0]) : $_[0]->copy->bpow($_[1]);
+ },
+'<<' => sub {
+ $_[2] ? ref($_[0])->new($_[1])->blsft($_[0]) : $_[0]->copy->blsft($_[1]);
+ },
+'>>' => sub {
+ $_[2] ? ref($_[0])->new($_[1])->brsft($_[0]) : $_[0]->copy->brsft($_[1]);
+ },
+'&' => sub {
+ $_[2] ? ref($_[0])->new($_[1])->band($_[0]) : $_[0]->copy->band($_[1]);
+ },
+'|' => sub {
+ $_[2] ? ref($_[0])->new($_[1])->bior($_[0]) : $_[0]->copy->bior($_[1]);
+ },
+'^' => sub {
+ $_[2] ? ref($_[0])->new($_[1])->bxor($_[0]) : $_[0]->copy->bxor($_[1]);
+ },
+
+# can modify arg of ++ and --, so avoid a copy() for speed, but don't
+# use $_[0]->bone(), it would modify $_[0] to be 1!
'++' => sub { $_[0]->binc() },
'--' => sub { $_[0]->bdec() },
# if overloaded, O(1) instead of O(N) and twice as fast for small numbers
'bool' => sub {
# this kludge is needed for perl prior 5.6.0 since returning 0 here fails :-/
- # v5.6.1 dumps on that: return !$_[0]->is_zero() || undef; :-(
- my $t = !$_[0]->is_zero();
- undef $t if $t == 0;
- return $t;
+ # v5.6.1 dumps on this: return !$_[0]->is_zero() || undef; :-(
+ my $t = undef;
+ $t = 1 if !$_[0]->is_zero();
+ $t;
},
-qw(
-"" bstr
-0+ numify), # Order of arguments unsignificant
+# the original qw() does not work with the TIESCALAR below, why?
+# Order of arguments unsignificant
+'""' => sub { $_[0]->bstr(); },
+'0+' => sub { $_[0]->numify(); }
;
##############################################################################
# global constants, flags and accessory
-# are NaNs ok?
-my $NaNOK=1;
-# set to 1 for tracing
-my $trace = 0;
-# constants for easier life
-my $nan = 'NaN';
-my $BASE_LEN = 5;
-my $BASE = int("1e".$BASE_LEN); # var for trying to change it to 1e7
-my $RBASE = 1e-5; # see USE_MUL
-
-# Rounding modes one of 'even', 'odd', '+inf', '-inf', 'zero' or 'trunc'
-$rnd_mode = 'even';
-$accuracy = undef;
-$precision = undef;
-$div_scale = 40;
+# These vars are public, but their direct usage is not recommended, use the
+# accessor methods instead
+
+$round_mode = 'even'; # one of 'even', 'odd', '+inf', '-inf', 'zero' or 'trunc'
+$accuracy = undef;
+$precision = undef;
+$div_scale = 40;
+
+$upgrade = undef; # default is no upgrade
+$downgrade = undef; # default is no downgrade
+
+# These are internally, and not to be used from the outside at all
+
+$_trap_nan = 0; # are NaNs ok? set w/ config()
+$_trap_inf = 0; # are infs ok? set w/ config()
+my $nan = 'NaN'; # constants for easier life
+
+my $CALC = 'Math::BigInt::FastCalc'; # module to do the low level math
+ # default is FastCalc.pm
+my $IMPORT = 0; # was import() called yet?
+ # used to make require work
+my %WARN; # warn only once for low-level libs
+my %CAN; # cache for $CALC->can(...)
+my %CALLBACKS; # callbacks to notify on lib loads
+my $EMU_LIB = 'Math/BigInt/CalcEmu.pm'; # emulate low-level math
+
+##############################################################################
+# the old code had $rnd_mode, so we need to support it, too
+
+$rnd_mode = 'even';
+sub TIESCALAR { my ($class) = @_; bless \$round_mode, $class; }
+sub FETCH { return $round_mode; }
+sub STORE { $rnd_mode = $_[0]->round_mode($_[1]); }
+
+BEGIN
+ {
+ # tie to enable $rnd_mode to work transparently
+ tie $rnd_mode, 'Math::BigInt';
+
+ # set up some handy alias names
+ *as_int = \&as_number;
+ *is_pos = \&is_positive;
+ *is_neg = \&is_negative;
+ }
+
+##############################################################################
sub round_mode
{
+ no strict 'refs';
# make Class->round_mode() work
- my $self = shift || $class;
- # shift @_ if defined $_[0] && $_[0] eq $class;
+ my $self = shift;
+ my $class = ref($self) || $self || __PACKAGE__;
if (defined $_[0])
{
my $m = shift;
- die "Unknown round mode $m"
- if $m !~ /^(even|odd|\+inf|\-inf|zero|trunc)$/;
- $rnd_mode = $m; return;
+ if ($m !~ /^(even|odd|\+inf|\-inf|zero|trunc)$/)
+ {
+ require Carp; Carp::croak ("Unknown round mode '$m'");
+ }
+ return ${"${class}::round_mode"} = $m;
}
- return $rnd_mode;
+ ${"${class}::round_mode"};
+ }
+
+sub upgrade
+ {
+ no strict 'refs';
+ # make Class->upgrade() work
+ my $self = shift;
+ my $class = ref($self) || $self || __PACKAGE__;
+ # need to set new value?
+ if (@_ > 0)
+ {
+ return ${"${class}::upgrade"} = $_[0];
+ }
+ ${"${class}::upgrade"};
+ }
+
+sub downgrade
+ {
+ no strict 'refs';
+ # make Class->downgrade() work
+ my $self = shift;
+ my $class = ref($self) || $self || __PACKAGE__;
+ # need to set new value?
+ if (@_ > 0)
+ {
+ return ${"${class}::downgrade"} = $_[0];
+ }
+ ${"${class}::downgrade"};
+ }
+
+sub div_scale
+ {
+ no strict 'refs';
+ # make Class->div_scale() work
+ my $self = shift;
+ my $class = ref($self) || $self || __PACKAGE__;
+ if (defined $_[0])
+ {
+ if ($_[0] < 0)
+ {
+ require Carp; Carp::croak ('div_scale must be greater than zero');
+ }
+ ${"${class}::div_scale"} = $_[0];
+ }
+ ${"${class}::div_scale"};
}
sub accuracy
{
- # $x->accuracy($a); ref($x) a
- # $x->accuracy(); ref($x);
- # Class::accuracy(); # not supported
- #print "MBI @_ ($class)\n";
- my $x = shift;
+ # $x->accuracy($a); ref($x) $a
+ # $x->accuracy(); ref($x)
+ # Class->accuracy(); class
+ # Class->accuracy($a); class $a
- die ("accuracy() needs reference to object as first parameter.")
- if !ref $x;
+ my $x = shift;
+ my $class = ref($x) || $x || __PACKAGE__;
+ no strict 'refs';
+ # need to set new value?
if (@_ > 0)
{
- $x->{_a} = shift;
- $x->round() if defined $x->{_a};
+ my $a = shift;
+ # convert objects to scalars to avoid deep recursion. If object doesn't
+ # have numify(), then hopefully it will have overloading for int() and
+ # boolean test without wandering into a deep recursion path...
+ $a = $a->numify() if ref($a) && $a->can('numify');
+
+ if (defined $a)
+ {
+ # also croak on non-numerical
+ if (!$a || $a <= 0)
+ {
+ require Carp;
+ Carp::croak ('Argument to accuracy must be greater than zero');
+ }
+ if (int($a) != $a)
+ {
+ require Carp; Carp::croak ('Argument to accuracy must be an integer');
+ }
+ }
+ if (ref($x))
+ {
+ # $object->accuracy() or fallback to global
+ $x->bround($a) if $a; # not for undef, 0
+ $x->{_a} = $a; # set/overwrite, even if not rounded
+ delete $x->{_p}; # clear P
+ $a = ${"${class}::accuracy"} unless defined $a; # proper return value
+ }
+ else
+ {
+ ${"${class}::accuracy"} = $a; # set global A
+ ${"${class}::precision"} = undef; # clear global P
+ }
+ return $a; # shortcut
}
- return $x->{_a};
- }
+
+ my $a;
+ # $object->accuracy() or fallback to global
+ $a = $x->{_a} if ref($x);
+ # but don't return global undef, when $x's accuracy is 0!
+ $a = ${"${class}::accuracy"} if !defined $a;
+ $a;
+ }
sub precision
{
+ # $x->precision($p); ref($x) $p
+ # $x->precision(); ref($x)
+ # Class->precision(); class
+ # Class->precision($p); class $p
+
my $x = shift;
+ my $class = ref($x) || $x || __PACKAGE__;
+
+ no strict 'refs';
+ if (@_ > 0)
+ {
+ my $p = shift;
+ # convert objects to scalars to avoid deep recursion. If object doesn't
+ # have numify(), then hopefully it will have overloading for int() and
+ # boolean test without wandering into a deep recursion path...
+ $p = $p->numify() if ref($p) && $p->can('numify');
+ if ((defined $p) && (int($p) != $p))
+ {
+ require Carp; Carp::croak ('Argument to precision must be an integer');
+ }
+ if (ref($x))
+ {
+ # $object->precision() or fallback to global
+ $x->bfround($p) if $p; # not for undef, 0
+ $x->{_p} = $p; # set/overwrite, even if not rounded
+ delete $x->{_a}; # clear A
+ $p = ${"${class}::precision"} unless defined $p; # proper return value
+ }
+ else
+ {
+ ${"${class}::precision"} = $p; # set global P
+ ${"${class}::accuracy"} = undef; # clear global A
+ }
+ return $p; # shortcut
+ }
+
+ my $p;
+ # $object->precision() or fallback to global
+ $p = $x->{_p} if ref($x);
+ # but don't return global undef, when $x's precision is 0!
+ $p = ${"${class}::precision"} if !defined $p;
+ $p;
+ }
- die ("precision() needs reference to object as first parameter.")
- unless ref $x;
+sub config
+ {
+ # return (or set) configuration data as hash ref
+ my $class = shift || 'Math::BigInt';
+ no strict 'refs';
if (@_ > 0)
{
- $x->{_p} = shift;
- $x->round() if defined $x->{_p};
+ # try to set given options as arguments from hash
+
+ my $args = $_[0];
+ if (ref($args) ne 'HASH')
+ {
+ $args = { @_ };
+ }
+ # these values can be "set"
+ my $set_args = {};
+ foreach my $key (
+ qw/trap_inf trap_nan
+ upgrade downgrade precision accuracy round_mode div_scale/
+ )
+ {
+ $set_args->{$key} = $args->{$key} if exists $args->{$key};
+ delete $args->{$key};
+ }
+ if (keys %$args > 0)
+ {
+ require Carp;
+ Carp::croak ("Illegal key(s) '",
+ join("','",keys %$args),"' passed to $class\->config()");
+ }
+ foreach my $key (keys %$set_args)
+ {
+ if ($key =~ /^trap_(inf|nan)\z/)
+ {
+ ${"${class}::_trap_$1"} = ($set_args->{"trap_$1"} ? 1 : 0);
+ next;
+ }
+ # use a call instead of just setting the $variable to check argument
+ $class->$key($set_args->{$key});
+ }
}
- return $x->{_p};
- }
+
+ # now return actual configuration
+
+ my $cfg = {
+ lib => $CALC,
+ lib_version => ${"${CALC}::VERSION"},
+ class => $class,
+ trap_nan => ${"${class}::_trap_nan"},
+ trap_inf => ${"${class}::_trap_inf"},
+ version => ${"${class}::VERSION"},
+ };
+ foreach my $key (qw/
+ upgrade downgrade precision accuracy round_mode div_scale
+ /)
+ {
+ $cfg->{$key} = ${"${class}::$key"};
+ };
+ $cfg;
+ }
sub _scale_a
{
# select accuracy parameter based on precedence,
# used by bround() and bfround(), may return undef for scale (means no op)
- my ($x,$s,$m,$scale,$mode) = @_;
- $scale = $x->{_a} if !defined $scale;
- $scale = $s if (!defined $scale);
- $mode = $m if !defined $mode;
- return ($scale,$mode);
+ my ($x,$scale,$mode) = @_;
+
+ $scale = $x->{_a} unless defined $scale;
+
+ no strict 'refs';
+ my $class = ref($x);
+
+ $scale = ${ $class . '::accuracy' } unless defined $scale;
+ $mode = ${ $class . '::round_mode' } unless defined $mode;
+
+ ($scale,$mode);
}
sub _scale_p
{
# select precision parameter based on precedence,
# used by bround() and bfround(), may return undef for scale (means no op)
- my ($x,$s,$m,$scale,$mode) = @_;
- $scale = $x->{_p} if !defined $scale;
- $scale = $s if (!defined $scale);
- $mode = $m if !defined $mode;
- return ($scale,$mode);
+ my ($x,$scale,$mode) = @_;
+
+ $scale = $x->{_p} unless defined $scale;
+
+ no strict 'refs';
+ my $class = ref($x);
+
+ $scale = ${ $class . '::precision' } unless defined $scale;
+ $mode = ${ $class . '::round_mode' } unless defined $mode;
+
+ ($scale,$mode);
}
##############################################################################
}
return unless ref($x); # only for objects
- my $self = {}; bless $self,$c;
- foreach my $k (keys %$x)
- {
- if (ref($x->{$k}) eq 'ARRAY')
- {
- $self->{$k} = [ @{$x->{$k}} ];
- }
- elsif (ref($x->{$k}) eq 'HASH')
- {
- # only one level deep!
- foreach my $h (keys %{$x->{$k}})
- {
- $self->{$k}->{$h} = $x->{$k}->{$h};
- }
- }
- elsif (ref($x->{$k}))
- {
- my $c = ref($x->{$k});
- $self->{$k} = $c->new($x->{$k}); # no copy() due to deep rec
- }
- else
- {
- $self->{$k} = $x->{$k};
- }
- }
+ my $self = bless {}, $c;
+
+ $self->{sign} = $x->{sign};
+ $self->{value} = $CALC->_copy($x->{value});
+ $self->{_a} = $x->{_a} if defined $x->{_a};
+ $self->{_p} = $x->{_p} if defined $x->{_p};
$self;
}
sub new
{
- # create a new BigInts object from a string or another bigint object.
- # value => internal array representation
- # sign => sign (+/-), or "NaN"
+ # create a new BigInt object from a string or another BigInt object.
+ # see hash keys documented at top
# the argument could be an object, so avoid ||, && etc on it, this would
- # cause costly overloaded code to be called. The only allowed op are ref()
- # and definend.
+ # cause costly overloaded code to be called. The only allowed ops are
+ # ref() and defined.
- trace (@_);
- my $class = shift;
+ my ($class,$wanted,$a,$p,$r) = @_;
- my $wanted = shift; # avoid numify call by not using || here
- return $class->bzero() if !defined $wanted; # default to 0
- return $class->copy($wanted) if ref($wanted);
+ # avoid numify-calls by not using || on $wanted!
+ return $class->bzero($a,$p) if !defined $wanted; # default to 0
+ return $class->copy($wanted,$a,$p,$r)
+ if ref($wanted) && $wanted->isa($class); # MBI or subclass
- my $self = {}; bless $self, $class;
- # handle '+inf', '-inf' first
- if ($wanted =~ /^[+-]inf$/)
+ $class->import() if $IMPORT == 0; # make require work
+
+ my $self = bless {}, $class;
+
+ # shortcut for "normal" numbers
+ if ((!ref $wanted) && ($wanted =~ /^([+-]?)[1-9][0-9]*\z/))
{
- $self->{value} = [ 0 ];
- $self->{sign} = $wanted;
+ $self->{sign} = $1 || '+';
+
+ if ($wanted =~ /^[+-]/)
+ {
+ # remove sign without touching wanted to make it work with constants
+ my $t = $wanted; $t =~ s/^[+-]//;
+ $self->{value} = $CALC->_new($t);
+ }
+ else
+ {
+ $self->{value} = $CALC->_new($wanted);
+ }
+ no strict 'refs';
+ if ( (defined $a) || (defined $p)
+ || (defined ${"${class}::precision"})
+ || (defined ${"${class}::accuracy"})
+ )
+ {
+ $self->round($a,$p,$r) unless (@_ == 4 && !defined $a && !defined $p);
+ }
return $self;
}
- # split str in m mantissa, e exponent, i integer, f fraction, v value, s sign
- my ($mis,$miv,$mfv,$es,$ev) = _split(\$wanted);
- if (ref $mis && !ref $miv)
+
+ # handle '+inf', '-inf' first
+ if ($wanted =~ /^[+-]?inf\z/)
{
- # _from_hex
- $self->{value} = $mis->{value};
- $self->{sign} = $mis->{sign};
- return $self;
+ $self->{sign} = $wanted; # set a default sign for bstr()
+ return $self->binf($wanted);
}
+ # split str in m mantissa, e exponent, i integer, f fraction, v value, s sign
+ my ($mis,$miv,$mfv,$es,$ev) = _split($wanted);
if (!ref $mis)
{
- die "$wanted is not a number initialized to $class" if !$NaNOK;
- #print "NaN 1\n";
- $self->{value} = [ 0 ];
+ if ($_trap_nan)
+ {
+ require Carp; Carp::croak("$wanted is not a number in $class");
+ }
+ $self->{value} = $CALC->_zero();
$self->{sign} = $nan;
return $self;
}
+ if (!ref $miv)
+ {
+ # _from_hex or _from_bin
+ $self->{value} = $mis->{value};
+ $self->{sign} = $mis->{sign};
+ return $self; # throw away $mis
+ }
# make integer from mantissa by adjusting exp, then convert to bigint
$self->{sign} = $$mis; # store sign
- $self->{value} = [ 0 ]; # for all the NaN cases
+ $self->{value} = $CALC->_zero(); # for all the NaN cases
my $e = int("$$es$$ev"); # exponent (avoid recursion)
if ($e > 0)
{
my $diff = $e - CORE::length($$mfv);
if ($diff < 0) # Not integer
{
+ if ($_trap_nan)
+ {
+ require Carp; Carp::croak("$wanted not an integer in $class");
+ }
#print "NOI 1\n";
+ return $upgrade->new($wanted,$a,$p,$r) if defined $upgrade;
$self->{sign} = $nan;
}
else # diff >= 0
{
# adjust fraction and add it to value
- # print "diff > 0 $$miv\n";
+ #print "diff > 0 $$miv\n";
$$miv = $$miv . ($$mfv . '0' x $diff);
}
}
if ($$mfv ne '') # e <= 0
{
# fraction and negative/zero E => NOI
+ if ($_trap_nan)
+ {
+ require Carp; Carp::croak("$wanted not an integer in $class");
+ }
#print "NOI 2 \$\$mfv '$$mfv'\n";
+ return $upgrade->new($wanted,$a,$p,$r) if defined $upgrade;
$self->{sign} = $nan;
}
elsif ($e < 0)
$e = abs($e);
if ($$miv !~ s/0{$e}$//) # can strip so many zero's?
{
+ if ($_trap_nan)
+ {
+ require Carp; Carp::croak("$wanted not an integer in $class");
+ }
#print "NOI 3\n";
+ return $upgrade->new($wanted,$a,$p,$r) if defined $upgrade;
$self->{sign} = $nan;
}
}
}
$self->{sign} = '+' if $$miv eq '0'; # normalize -0 => +0
- $self->_internal($miv) if $self->{sign} ne $nan; # as internal array
- #print "$wanted => $self->{sign} $self->{value}->[0]\n";
- # if any of the globals is set, round to them and thus store them insid $self
- $self->round($accuracy,$precision,$rnd_mode)
- if defined $accuracy || defined $precision;
- return $self;
- }
-
-# some shortcuts for easier life
-sub bint
- {
- # exportable version of new
- trace(@_);
- return $class->new(@_);
+ $self->{value} = $CALC->_new($$miv) if $self->{sign} =~ /^[+-]$/;
+ # if any of the globals is set, use them to round and store them inside $self
+ # do not round for new($x,undef,undef) since that is used by MBF to signal
+ # no rounding
+ $self->round($a,$p,$r) unless @_ == 4 && !defined $a && !defined $p;
+ $self;
}
sub bnan
{
my $c = $self; $self = {}; bless $self, $c;
}
+ no strict 'refs';
+ if (${"${class}::_trap_nan"})
+ {
+ require Carp;
+ Carp::croak ("Tried to set $self to NaN in $class\::bnan()");
+ }
+ $self->import() if $IMPORT == 0; # make require work
return if $self->modify('bnan');
- $self->{value} = [ 0 ];
+ if ($self->can('_bnan'))
+ {
+ # use subclass to initialize
+ $self->_bnan();
+ }
+ else
+ {
+ # otherwise do our own thing
+ $self->{value} = $CALC->_zero();
+ }
$self->{sign} = $nan;
- trace('NaN');
- return $self;
+ delete $self->{_a}; delete $self->{_p}; # rounding NaN is silly
+ $self;
}
sub binf
# create a bigint '+-inf', if given a BigInt, set it to '+-inf'
# the sign is either '+', or if given, used from there
my $self = shift;
- my $sign = shift; $sign = '+' if !defined $sign || $sign ne '-';
+ my $sign = shift; $sign = '+' if !defined $sign || $sign !~ /^-(inf)?$/;
$self = $class if !defined $self;
if (!ref($self))
{
my $c = $self; $self = {}; bless $self, $c;
}
+ no strict 'refs';
+ if (${"${class}::_trap_inf"})
+ {
+ require Carp;
+ Carp::croak ("Tried to set $self to +-inf in $class\::binf()");
+ }
+ $self->import() if $IMPORT == 0; # make require work
return if $self->modify('binf');
- $self->{value} = [ 0 ];
- $self->{sign} = $sign.'inf';
- trace('inf');
- return $self;
+ if ($self->can('_binf'))
+ {
+ # use subclass to initialize
+ $self->_binf();
+ }
+ else
+ {
+ # otherwise do our own thing
+ $self->{value} = $CALC->_zero();
+ }
+ $sign = $sign . 'inf' if $sign !~ /inf$/; # - => -inf
+ $self->{sign} = $sign;
+ ($self->{_a},$self->{_p}) = @_; # take over requested rounding
+ $self;
}
sub bzero
{
# create a bigint '+0', if given a BigInt, set it to 0
my $self = shift;
- $self = $class if !defined $self;
+ $self = __PACKAGE__ if !defined $self;
+
if (!ref($self))
{
my $c = $self; $self = {}; bless $self, $c;
}
+ $self->import() if $IMPORT == 0; # make require work
return if $self->modify('bzero');
- $self->{value} = [ 0 ];
+
+ if ($self->can('_bzero'))
+ {
+ # use subclass to initialize
+ $self->_bzero();
+ }
+ else
+ {
+ # otherwise do our own thing
+ $self->{value} = $CALC->_zero();
+ }
$self->{sign} = '+';
- trace('0');
- return $self;
+ if (@_ > 0)
+ {
+ if (@_ > 3)
+ {
+ # call like: $x->bzero($a,$p,$r,$y);
+ ($self,$self->{_a},$self->{_p}) = $self->_find_round_parameters(@_);
+ }
+ else
+ {
+ $self->{_a} = $_[0]
+ if ( (!defined $self->{_a}) || (defined $_[0] && $_[0] > $self->{_a}));
+ $self->{_p} = $_[1]
+ if ( (!defined $self->{_p}) || (defined $_[1] && $_[1] > $self->{_p}));
+ }
+ }
+ $self;
+ }
+
+sub bone
+ {
+ # create a bigint '+1' (or -1 if given sign '-'),
+ # if given a BigInt, set it to +1 or -1, respectively
+ my $self = shift;
+ my $sign = shift; $sign = '+' if !defined $sign || $sign ne '-';
+ $self = $class if !defined $self;
+
+ if (!ref($self))
+ {
+ my $c = $self; $self = {}; bless $self, $c;
+ }
+ $self->import() if $IMPORT == 0; # make require work
+ return if $self->modify('bone');
+
+ if ($self->can('_bone'))
+ {
+ # use subclass to initialize
+ $self->_bone();
+ }
+ else
+ {
+ # otherwise do our own thing
+ $self->{value} = $CALC->_one();
+ }
+ $self->{sign} = $sign;
+ if (@_ > 0)
+ {
+ if (@_ > 3)
+ {
+ # call like: $x->bone($sign,$a,$p,$r,$y);
+ ($self,$self->{_a},$self->{_p}) = $self->_find_round_parameters(@_);
+ }
+ else
+ {
+ # call like: $x->bone($sign,$a,$p,$r);
+ $self->{_a} = $_[0]
+ if ( (!defined $self->{_a}) || (defined $_[0] && $_[0] > $self->{_a}));
+ $self->{_p} = $_[1]
+ if ( (!defined $self->{_p}) || (defined $_[1] && $_[1] > $self->{_p}));
+ }
+ }
+ $self;
}
##############################################################################
# (ref to BFLOAT or num_str ) return num_str
# Convert number from internal format to scientific string format.
# internal format is always normalized (no leading zeros, "-0E0" => "+0E0")
- trace(@_);
- my ($self,$x) = objectify(1,@_);
+ my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
- return $x->{sign} if $x->{sign} !~ /^[+-]$/;
+ if ($x->{sign} !~ /^[+-]$/)
+ {
+ return $x->{sign} unless $x->{sign} eq '+inf'; # -inf, NaN
+ return 'inf'; # +inf
+ }
my ($m,$e) = $x->parts();
- # can be only '+', so
- my $sign = 'e+';
- # MBF: my $s = $e->{sign}; $s = '' if $s eq '-'; my $sep = 'e'.$s;
- return $m->bstr().$sign.$e->bstr();
+ #$m->bstr() . 'e+' . $e->bstr(); # e can only be positive in BigInt
+ # 'e+' because E can only be positive in BigInt
+ $m->bstr() . 'e+' . $CALC->_str($e->{value});
}
sub bstr
{
- # (ref to BINT or num_str ) return num_str
- # Convert number from internal base 100000 format to string format.
- # internal format is always normalized (no leading zeros, "-0" => "+0")
- trace(@_);
- my $x = shift; $x = $class->new($x) unless ref $x;
- # my ($self,$x) = objectify(1,@_);
+ # make a string from bigint object
+ my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
- return $x->{sign} if $x->{sign} !~ /^[+-]$/;
- my $ar = $x->{value} || return $nan; # should not happen
- my $es = "";
- $es = $x->{sign} if $x->{sign} eq '-'; # get sign, but not '+'
- my $l = scalar @$ar; # number of parts
- return $nan if $l < 1; # should not happen
- # handle first one different to strip leading zeros from it (there are no
- # leading zero parts in internal representation)
- $l --; $es .= $ar->[$l]; $l--;
- # Interestingly, the pre-padd method uses more time
- # the old grep variant takes longer (14 to 10 sec)
- while ($l >= 0)
+ if ($x->{sign} !~ /^[+-]$/)
{
- $es .= substr('0000'.$ar->[$l],-5); # fastest way I could think of
- $l--;
+ return $x->{sign} unless $x->{sign} eq '+inf'; # -inf, NaN
+ return 'inf'; # +inf
}
- return $es;
+ my $es = ''; $es = $x->{sign} if $x->{sign} eq '-';
+ $es.$CALC->_str($x->{value});
}
sub numify
{
- # Make a number from a BigInt object
- # old: simple return string and let Perl's atoi() handle the rest
- # new: calc because it is faster than bstr()+atoi()
- #trace (@_);
- #my ($self,$x) = objectify(1,@_);
- #return $x->bstr(); # ref($x);
+ # Make a "normal" scalar from a BigInt object
my $x = shift; $x = $class->new($x) unless ref $x;
- return $nan if $x->{sign} eq $nan;
- my $fac = 1; $fac = -1 if $x->{sign} eq '-';
- return $fac*$x->{value}->[0] if @{$x->{value}} == 1; # below $BASE
- my $num = 0;
- foreach (@{$x->{value}})
- {
- $num += $fac*$_; $fac *= $BASE;
- }
- return $num;
+ return $x->bstr() if $x->{sign} !~ /^[+-]$/;
+ my $num = $CALC->_num($x->{value});
+ return -$num if $x->{sign} eq '-';
+ $num;
}
##############################################################################
sub sign
{
- # return the sign of the number: +/-/NaN
- my ($self,$x) = objectify(1,@_);
- return $x->{sign};
+ # return the sign of the number: +/-/-inf/+inf/NaN
+ my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
+
+ $x->{sign};
}
-sub round
+sub _find_round_parameters
{
# After any operation or when calling round(), the result is rounded by
# regarding the A & P from arguments, local parameters, or globals.
- # The result's A or P are set by the rounding, but not inspected beforehand
- # (aka only the arguments enter into it). This works because the given
- # 'first' argument is both the result and true first argument with unchanged
- # A and P settings.
- # This does not yet handle $x with A, and $y with P (which should be an
- # error).
- my $self = shift;
- my $a = shift; # accuracy, if given by caller
- my $p = shift; # precision, if given by caller
- my $r = shift; # round_mode, if given by caller
- my @args = @_; # all 'other' arguments (0 for unary, 1 for binary ops)
- unshift @args,$self; # add 'first' argument
+ # !!!!!!! If you change this, remember to change round(), too! !!!!!!!!!!
- $self = new($self) unless ref($self); # if not object, make one
+ # This procedure finds the round parameters, but it is for speed reasons
+ # duplicated in round. Otherwise, it is tested by the testsuite and used
+ # by fdiv().
+
+ # returns ($self) or ($self,$a,$p,$r) - sets $self to NaN of both A and P
+ # were requested/defined (locally or globally or both)
+
+ my ($self,$a,$p,$r,@args) = @_;
+ # $a accuracy, if given by caller
+ # $p precision, if given by caller
+ # $r round_mode, if given by caller
+ # @args all 'other' arguments (0 for unary, 1 for binary ops)
- # find out class of argument to round
- my $c = ref($args[0]);
+ my $c = ref($self); # find out class of argument(s)
+ no strict 'refs';
# now pick $a or $p, but only if we have got "arguments"
- if ((!defined $a) && (!defined $p) && (@args > 0))
+ if (!defined $a)
{
- foreach (@args)
+ foreach ($self,@args)
{
# take the defined one, or if both defined, the one that is smaller
$a = $_->{_a} if (defined $_->{_a}) && (!defined $a || $_->{_a} < $a);
}
- if (!defined $a) # if it still is not defined, take p
- {
- foreach (@args)
- {
- # take the defined one, or if both defined, the one that is smaller
- $p = $_->{_p} if (defined $_->{_p}) && (!defined $p || $_->{_p} < $p);
- }
- # if none defined, use globals (#2)
- if (!defined $p)
- {
- no strict 'refs';
- my $z = "$c\::accuracy"; $a = $$z;
- if (!defined $a)
- {
- $z = "$c\::precision"; $p = $$z;
- }
- }
- } # endif !$a
- } # endif !$a || !$P && args > 0
- # for clearity, this is not merged at place (#2)
- # now round, by calling fround or ffround:
- if (defined $a)
- {
- $self->{_a} = $a; $self->bround($a,$r);
}
- elsif (defined $p)
+ if (!defined $p)
{
- $self->{_p} = $p; $self->bfround($p,$r);
+ # even if $a is defined, take $p, to signal error for both defined
+ foreach ($self,@args)
+ {
+ # take the defined one, or if both defined, the one that is bigger
+ # -2 > -3, and 3 > 2
+ $p = $_->{_p} if (defined $_->{_p}) && (!defined $p || $_->{_p} > $p);
+ }
}
- return $self->bnorm();
- }
+ # if still none defined, use globals (#2)
+ $a = ${"$c\::accuracy"} unless defined $a;
+ $p = ${"$c\::precision"} unless defined $p;
-sub bnorm
- {
- # (num_str or BINT) return BINT
- # Normalize number -- no-op here
- my $self = shift;
+ # A == 0 is useless, so undef it to signal no rounding
+ $a = undef if defined $a && $a == 0;
+
+ # no rounding today?
+ return ($self) unless defined $a || defined $p; # early out
+
+ # set A and set P is an fatal error
+ return ($self->bnan()) if defined $a && defined $p; # error
+
+ $r = ${"$c\::round_mode"} unless defined $r;
+ if ($r !~ /^(even|odd|\+inf|\-inf|zero|trunc)$/)
+ {
+ require Carp; Carp::croak ("Unknown round mode '$r'");
+ }
- return $self;
+ ($self,$a,$p,$r);
}
-sub babs
+sub round
{
- # (BINT or num_str) return BINT
- # make number absolute, or return absolute BINT from string
- #my ($self,$x) = objectify(1,@_);
- my $x = shift; $x = $class->new($x) unless ref $x;
- return $x if $x->modify('babs');
- # post-normalized abs for internal use (does nothing for NaN)
- $x->{sign} =~ s/^-/+/;
- $x;
- }
+ # Round $self according to given parameters, or given second argument's
+ # parameters or global defaults
+
+ # for speed reasons, _find_round_parameters is embeded here:
+
+ my ($self,$a,$p,$r,@args) = @_;
+ # $a accuracy, if given by caller
+ # $p precision, if given by caller
+ # $r round_mode, if given by caller
+ # @args all 'other' arguments (0 for unary, 1 for binary ops)
+
+ my $c = ref($self); # find out class of argument(s)
+ no strict 'refs';
+
+ # now pick $a or $p, but only if we have got "arguments"
+ if (!defined $a)
+ {
+ foreach ($self,@args)
+ {
+ # take the defined one, or if both defined, the one that is smaller
+ $a = $_->{_a} if (defined $_->{_a}) && (!defined $a || $_->{_a} < $a);
+ }
+ }
+ if (!defined $p)
+ {
+ # even if $a is defined, take $p, to signal error for both defined
+ foreach ($self,@args)
+ {
+ # take the defined one, or if both defined, the one that is bigger
+ # -2 > -3, and 3 > 2
+ $p = $_->{_p} if (defined $_->{_p}) && (!defined $p || $_->{_p} > $p);
+ }
+ }
+ # if still none defined, use globals (#2)
+ $a = ${"$c\::accuracy"} unless defined $a;
+ $p = ${"$c\::precision"} unless defined $p;
+
+ # A == 0 is useless, so undef it to signal no rounding
+ $a = undef if defined $a && $a == 0;
+
+ # no rounding today?
+ return $self unless defined $a || defined $p; # early out
+
+ # set A and set P is an fatal error
+ return $self->bnan() if defined $a && defined $p;
+
+ $r = ${"$c\::round_mode"} unless defined $r;
+ if ($r !~ /^(even|odd|\+inf|\-inf|zero|trunc)$/)
+ {
+ require Carp; Carp::croak ("Unknown round mode '$r'");
+ }
+
+ # now round, by calling either fround or ffround:
+ if (defined $a)
+ {
+ $self->bround($a,$r) if !defined $self->{_a} || $self->{_a} >= $a;
+ }
+ else # both can't be undefined due to early out
+ {
+ $self->bfround($p,$r) if !defined $self->{_p} || $self->{_p} <= $p;
+ }
+ # bround() or bfround() already callled bnorm() if necc.
+ $self;
+ }
+
+sub bnorm
+ {
+ # (numstr or BINT) return BINT
+ # Normalize number -- no-op here
+ my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
+ $x;
+ }
+
+sub babs
+ {
+ # (BINT or num_str) return BINT
+ # make number absolute, or return absolute BINT from string
+ my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
+
+ return $x if $x->modify('babs');
+ # post-normalized abs for internal use (does nothing for NaN)
+ $x->{sign} =~ s/^-/+/;
+ $x;
+ }
sub bneg
{
# (BINT or num_str) return BINT
# negate number or make a negated number from string
- my ($self,$x,$a,$p,$r) = objectify(1,@_);
+ my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
+
return $x if $x->modify('bneg');
- # for +0 dont negate (to have always normalized)
- return $x if $x->is_zero();
- $x->{sign} =~ tr/+\-/-+/; # does nothing for NaN
- # $x->round($a,$p,$r); # changing this makes $x - $y modify $y!!
+
+ # for +0 dont negate (to have always normalized +0). Does nothing for 'NaN'
+ $x->{sign} =~ tr/+-/-+/ unless ($x->{sign} eq '+' && $CALC->_is_zero($x->{value}));
$x;
}
{
# Compares 2 values. Returns one of undef, <0, =0, >0. (suitable for sort)
# (BINT or num_str, BINT or num_str) return cond_code
- my ($self,$x,$y) = objectify(2,@_);
- return undef if (($x->{sign} eq $nan) || ($y->{sign} eq $nan));
- &cmp($x->{value},$y->{value},$x->{sign},$y->{sign}) <=> 0;
+
+ # set up parameters
+ my ($self,$x,$y) = (ref($_[0]),@_);
+
+ # objectify is costly, so avoid it
+ if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
+ {
+ ($self,$x,$y) = objectify(2,@_);
+ }
+
+ return $upgrade->bcmp($x,$y) if defined $upgrade &&
+ ((!$x->isa($self)) || (!$y->isa($self)));
+
+ if (($x->{sign} !~ /^[+-]$/) || ($y->{sign} !~ /^[+-]$/))
+ {
+ # handle +-inf and NaN
+ return undef if (($x->{sign} eq $nan) || ($y->{sign} eq $nan));
+ return 0 if $x->{sign} eq $y->{sign} && $x->{sign} =~ /^[+-]inf$/;
+ return +1 if $x->{sign} eq '+inf';
+ return -1 if $x->{sign} eq '-inf';
+ return -1 if $y->{sign} eq '+inf';
+ return +1;
+ }
+ # check sign for speed first
+ return 1 if $x->{sign} eq '+' && $y->{sign} eq '-'; # does also 0 <=> -y
+ return -1 if $x->{sign} eq '-' && $y->{sign} eq '+'; # does also -x <=> 0
+
+ # have same sign, so compare absolute values. Don't make tests for zero here
+ # because it's actually slower than testin in Calc (especially w/ Pari et al)
+
+ # post-normalized compare for internal use (honors signs)
+ if ($x->{sign} eq '+')
+ {
+ # $x and $y both > 0
+ return $CALC->_acmp($x->{value},$y->{value});
+ }
+
+ # $x && $y both < 0
+ $CALC->_acmp($y->{value},$x->{value}); # swaped acmp (lib returns 0,1,-1)
}
sub bacmp
# Compares 2 values, ignoring their signs.
# Returns one of undef, <0, =0, >0. (suitable for sort)
# (BINT, BINT) return cond_code
- my ($self,$x,$y) = objectify(2,@_);
- return undef if (($x->{sign} eq $nan) || ($y->{sign} eq $nan));
- acmp($x->{value},$y->{value}) <=> 0;
+
+ # set up parameters
+ my ($self,$x,$y) = (ref($_[0]),@_);
+ # objectify is costly, so avoid it
+ if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
+ {
+ ($self,$x,$y) = objectify(2,@_);
+ }
+
+ return $upgrade->bacmp($x,$y) if defined $upgrade &&
+ ((!$x->isa($self)) || (!$y->isa($self)));
+
+ if (($x->{sign} !~ /^[+-]$/) || ($y->{sign} !~ /^[+-]$/))
+ {
+ # handle +-inf and NaN
+ return undef if (($x->{sign} eq $nan) || ($y->{sign} eq $nan));
+ return 0 if $x->{sign} =~ /^[+-]inf$/ && $y->{sign} =~ /^[+-]inf$/;
+ return 1 if $x->{sign} =~ /^[+-]inf$/ && $y->{sign} !~ /^[+-]inf$/;
+ return -1;
+ }
+ $CALC->_acmp($x->{value},$y->{value}); # lib does only 0,1,-1
}
sub badd
{
# add second arg (BINT or string) to first (BINT) (modifies first)
# return result as BINT
- trace(@_);
- my ($self,$x,$y,$a,$p,$r) = objectify(2,@_);
+
+ # set up parameters
+ my ($self,$x,$y,@r) = (ref($_[0]),@_);
+ # objectify is costly, so avoid it
+ if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
+ {
+ ($self,$x,$y,@r) = objectify(2,@_);
+ }
return $x if $x->modify('badd');
- return $x->bnan() if (($x->{sign} eq $nan) || ($y->{sign} eq $nan));
+ return $upgrade->badd($upgrade->new($x),$upgrade->new($y),@r) if defined $upgrade &&
+ ((!$x->isa($self)) || (!$y->isa($self)));
- # for round calls, make array
- my @bn = ($a,$p,$r,$y);
- # speed: no add for 0+y or x+0
- return $x->bnorm(@bn) if $y->is_zero(); # x+0
- if ($x->is_zero()) # 0+y
+ $r[3] = $y; # no push!
+ # inf and NaN handling
+ if (($x->{sign} !~ /^[+-]$/) || ($y->{sign} !~ /^[+-]$/))
{
- # make copy, clobbering up x
- $x->{value} = [ @{$y->{value}} ];
- $x->{sign} = $y->{sign} || $nan;
- return $x->round(@bn);
+ # NaN first
+ return $x->bnan() if (($x->{sign} eq $nan) || ($y->{sign} eq $nan));
+ # inf handling
+ if (($x->{sign} =~ /^[+-]inf$/) && ($y->{sign} =~ /^[+-]inf$/))
+ {
+ # +inf++inf or -inf+-inf => same, rest is NaN
+ return $x if $x->{sign} eq $y->{sign};
+ return $x->bnan();
+ }
+ # +-inf + something => +inf
+ # something +-inf => +-inf
+ $x->{sign} = $y->{sign}, return $x if $y->{sign} =~ /^[+-]inf$/;
+ return $x;
}
-
- # shortcuts
- my $xv = $x->{value};
- my $yv = $y->{value};
- my ($sx, $sy) = ( $x->{sign}, $y->{sign} ); # get signs
+
+ my ($sx, $sy) = ( $x->{sign}, $y->{sign} ); # get signs
if ($sx eq $sy)
{
- add($xv,$yv); # if same sign, absolute add
- $x->{sign} = $sx;
+ $x->{value} = $CALC->_add($x->{value},$y->{value}); # same sign, abs add
}
else
{
- my $a = acmp ($yv,$xv); # absolute compare
+ my $a = $CALC->_acmp ($y->{value},$x->{value}); # absolute compare
if ($a > 0)
{
- #print "swapped sub (a=$a)\n";
- &sub($yv,$xv,1); # absolute sub w/ swapped params
+ $x->{value} = $CALC->_sub($y->{value},$x->{value},1); # abs sub w/ swap
$x->{sign} = $sy;
}
elsif ($a == 0)
{
# speedup, if equal, set result to 0
- $x->{value} = [ 0 ];
+ $x->{value} = $CALC->_zero();
$x->{sign} = '+';
}
else # a < 0
{
- #print "unswapped sub (a=$a)\n";
- &sub($xv, $yv); # absolute sub
- $x->{sign} = $sx;
+ $x->{value} = $CALC->_sub($x->{value}, $y->{value}); # abs sub
}
}
- return $x->round(@bn);
+ $x->round(@r);
}
sub bsub
{
- # (BINT or num_str, BINT or num_str) return num_str
+ # (BINT or num_str, BINT or num_str) return BINT
# subtract second arg from first, modify first
- my ($self,$x,$y,$a,$p,$r) = objectify(2,@_);
+
+ # set up parameters
+ my ($self,$x,$y,@r) = (ref($_[0]),@_);
+ # objectify is costly, so avoid it
+ if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
+ {
+ ($self,$x,$y,@r) = objectify(2,@_);
+ }
- trace(@_);
return $x if $x->modify('bsub');
- $x->badd($y->bneg()); # badd does not leave internal zeros
- $y->bneg(); # refix y, assumes no one reads $y in between
- return $x->round($a,$p,$r,$y);
+
+ return $upgrade->new($x)->bsub($upgrade->new($y),@r) if defined $upgrade &&
+ ((!$x->isa($self)) || (!$y->isa($self)));
+
+ return $x->round(@r) if $y->is_zero();
+
+ # To correctly handle the lone special case $x->bsub($x), we note the sign
+ # of $x, then flip the sign from $y, and if the sign of $x did change, too,
+ # then we caught the special case:
+ my $xsign = $x->{sign};
+ $y->{sign} =~ tr/+\-/-+/; # does nothing for NaN
+ if ($xsign ne $x->{sign})
+ {
+ # special case of $x->bsub($x) results in 0
+ return $x->bzero(@r) if $xsign =~ /^[+-]$/;
+ return $x->bnan(); # NaN, -inf, +inf
+ }
+ $x->badd($y,@r); # badd does not leave internal zeros
+ $y->{sign} =~ tr/+\-/-+/; # refix $y (does nothing for NaN)
+ $x; # already rounded by badd() or no round necc.
}
sub binc
{
# increment arg by one
- my ($self,$x,$a,$p,$r) = objectify(1,@_);
- # my $x = shift; $x = $class->new($x) unless ref $x; my $self = ref($x);
- trace(@_);
+ my ($self,$x,$a,$p,$r) = ref($_[0]) ? (ref($_[0]),@_) : objectify(1,@_);
return $x if $x->modify('binc');
- $x->badd($self->_one())->round($a,$p,$r);
+
+ if ($x->{sign} eq '+')
+ {
+ $x->{value} = $CALC->_inc($x->{value});
+ return $x->round($a,$p,$r);
+ }
+ elsif ($x->{sign} eq '-')
+ {
+ $x->{value} = $CALC->_dec($x->{value});
+ $x->{sign} = '+' if $CALC->_is_zero($x->{value}); # -1 +1 => -0 => +0
+ return $x->round($a,$p,$r);
+ }
+ # inf, nan handling etc
+ $x->badd($self->bone(),$a,$p,$r); # badd does round
}
sub bdec
{
# decrement arg by one
- my ($self,$x,$a,$p,$r) = objectify(1,@_);
- trace(@_);
+ my ($self,$x,@r) = ref($_[0]) ? (ref($_[0]),@_) : objectify(1,@_);
return $x if $x->modify('bdec');
- $x->badd($self->_one('-'))->round($a,$p,$r);
- }
+
+ if ($x->{sign} eq '-')
+ {
+ # x already < 0
+ $x->{value} = $CALC->_inc($x->{value});
+ }
+ else
+ {
+ return $x->badd($self->bone('-'),@r) unless $x->{sign} eq '+'; # inf or NaN
+ # >= 0
+ if ($CALC->_is_zero($x->{value}))
+ {
+ # == 0
+ $x->{value} = $CALC->_one(); $x->{sign} = '-'; # 0 => -1
+ }
+ else
+ {
+ # > 0
+ $x->{value} = $CALC->_dec($x->{value});
+ }
+ }
+ $x->round(@r);
+ }
+
+sub blog
+ {
+ # calculate $x = $a ** $base + $b and return $a (e.g. the log() to base
+ # $base of $x)
+
+ # set up parameters
+ my ($self,$x,$base,@r) = (undef,@_);
+ # objectify is costly, so avoid it
+ if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
+ {
+ ($self,$x,$base,@r) = objectify(1,ref($x),@_);
+ }
+
+ return $x if $x->modify('blog');
+
+ # inf, -inf, NaN, <0 => NaN
+ return $x->bnan()
+ if $x->{sign} ne '+' || (defined $base && $base->{sign} ne '+');
+
+ return $upgrade->blog($upgrade->new($x),$base,@r) if
+ defined $upgrade;
+
+ my ($rc,$exact) = $CALC->_log_int($x->{value},$base->{value});
+ return $x->bnan() unless defined $rc; # not possible to take log?
+ $x->{value} = $rc;
+ $x->round(@r);
+ }
sub blcm
{
# (BINT or num_str, BINT or num_str) return BINT
# does not modify arguments, but returns new object
# Lowest Common Multiplicator
- trace(@_);
- my ($self,@arg) = objectify(0,@_);
- my $x = $self->new(shift @arg);
- while (@arg) { $x = _lcm($x,shift @arg); }
+ my $y = shift; my ($x);
+ if (ref($y))
+ {
+ $x = $y->copy();
+ }
+ else
+ {
+ $x = $class->new($y);
+ }
+ my $self = ref($x);
+ while (@_)
+ {
+ my $y = shift; $y = $self->new($y) if !ref ($y);
+ $x = __lcm($x,$y);
+ }
$x;
}
# (BINT or num_str, BINT or num_str) return BINT
# does not modify arguments, but returns new object
# GCD -- Euclids algorithm, variant C (Knuth Vol 3, pg 341 ff)
- trace(@_);
-
- my ($self,@arg) = objectify(0,@_);
- my $x = $self->new(shift @arg);
- while (@arg)
+
+ my $y = shift;
+ $y = $class->new($y) if !ref($y);
+ my $self = ref($y);
+ my $x = $y->copy()->babs(); # keep arguments
+ return $x->bnan() if $x->{sign} !~ /^[+-]$/; # x NaN?
+
+ while (@_)
{
- #$x = _gcd($x,shift @arg); last if $x->is_one(); # new fast, but is slower
- $x = _gcd_old($x,shift @arg); last if $x->is_one(); # old, slow, but faster
- }
+ $y = shift; $y = $self->new($y) if !ref($y);
+ return $x->bnan() if $y->{sign} !~ /^[+-]$/; # y NaN?
+ $x->{value} = $CALC->_gcd($x->{value},$y->{value});
+ last if $CALC->_is_one($x->{value});
+ }
$x;
}
-sub bmod
- {
- # modulus
- # (BINT or num_str, BINT or num_str) return BINT
- my ($self,$x,$y) = objectify(2,@_);
-
- return $x if $x->modify('bmod');
- (&bdiv($self,$x,$y))[1];
- }
-
sub bnot
{
# (num_str or BINT) return BINT
# represent ~x as twos-complement number
- my ($self,$x) = objectify(1,@_);
+ # we don't need $self, so undef instead of ref($_[0]) make it slightly faster
+ my ($self,$x,$a,$p,$r) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
+
return $x if $x->modify('bnot');
- $x->bneg(); $x->bdec(); # was: bsub(-1,$x);, time it someday
- $x;
+ $x->binc()->bneg(); # binc already does round
}
+##############################################################################
+# is_foo test routines
+# we don't need $self, so undef instead of ref($_[0]) make it slightly faster
+
sub is_zero
{
# return true if arg (BINT or num_str) is zero (array '+', '0')
- #my ($self,$x) = objectify(1,@_);
- #trace(@_);
- my $x = shift; $x = $class->new($x) unless ref $x;
- return (@{$x->{value}} == 1) && ($x->{sign} eq '+')
- && ($x->{value}->[0] == 0);
+ my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
+
+ return 0 if $x->{sign} !~ /^\+$/; # -, NaN & +-inf aren't
+ $CALC->_is_zero($x->{value});
}
sub is_nan
{
# return true if arg (BINT or num_str) is NaN
- #my ($self,$x) = objectify(1,@_);
- #trace(@_);
- my $x = shift; $x = $class->new($x) unless ref $x;
- return ($x->{sign} eq $nan);
+ my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
+
+ $x->{sign} eq $nan ? 1 : 0;
}
sub is_inf
{
# return true if arg (BINT or num_str) is +-inf
- #my ($self,$x) = objectify(1,@_);
- #trace(@_);
- my $x = shift; $x = $class->new($x) unless ref $x;
- my $sign = shift || '';
+ my ($self,$x,$sign) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
- return $x->{sign} =~ /^[+-]inf/ if $sign eq '';
- return $x->{sign} =~ /^[$sign]inf/;
+ if (defined $sign)
+ {
+ $sign = '[+-]inf' if $sign eq ''; # +- doesn't matter, only that's inf
+ $sign = "[$1]inf" if $sign =~ /^([+-])(inf)?$/; # extract '+' or '-'
+ return $x->{sign} =~ /^$sign$/ ? 1 : 0;
+ }
+ $x->{sign} =~ /^[+-]inf$/ ? 1 : 0; # only +-inf is infinity
}
sub is_one
{
- # return true if arg (BINT or num_str) is +1 (array '+', '1')
- # or -1 if signis given
- #my ($self,$x) = objectify(1,@_);
- my $x = shift; $x = $class->new($x) unless ref $x;
- my $sign = shift || '+'; #$_[2] || '+';
- return (@{$x->{value}} == 1) && ($x->{sign} eq $sign)
- && ($x->{value}->[0] == 1);
+ # return true if arg (BINT or num_str) is +1, or -1 if sign is given
+ my ($self,$x,$sign) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
+
+ $sign = '+' if !defined $sign || $sign ne '-';
+
+ return 0 if $x->{sign} ne $sign; # -1 != +1, NaN, +-inf aren't either
+ $CALC->_is_one($x->{value});
}
sub is_odd
{
# return true when arg (BINT or num_str) is odd, false for even
- my $x = shift; $x = $class->new($x) unless ref $x;
- #my ($self,$x) = objectify(1,@_);
- return (($x->{sign} ne $nan) && ($x->{value}->[0] & 1));
+ my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
+
+ return 0 if $x->{sign} !~ /^[+-]$/; # NaN & +-inf aren't
+ $CALC->_is_odd($x->{value});
}
sub is_even
{
# return true when arg (BINT or num_str) is even, false for odd
- my $x = shift; $x = $class->new($x) unless ref $x;
- #my ($self,$x) = objectify(1,@_);
- return (($x->{sign} ne $nan) && (!($x->{value}->[0] & 1)));
+ my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
+
+ return 0 if $x->{sign} !~ /^[+-]$/; # NaN & +-inf aren't
+ $CALC->_is_even($x->{value});
+ }
+
+sub is_positive
+ {
+ # return true when arg (BINT or num_str) is positive (>= 0)
+ my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
+
+ return 1 if $x->{sign} eq '+inf'; # +inf is positive
+
+ # 0+ is neither positive nor negative
+ ($x->{sign} eq '+' && !$x->is_zero()) ? 1 : 0;
+ }
+
+sub is_negative
+ {
+ # return true when arg (BINT or num_str) is negative (< 0)
+ my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
+
+ $x->{sign} =~ /^-/ ? 1 : 0; # -inf is negative, but NaN is not
+ }
+
+sub is_int
+ {
+ # return true when arg (BINT or num_str) is an integer
+ # always true for BigInt, but different for BigFloats
+ my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
+
+ $x->{sign} =~ /^[+-]$/ ? 1 : 0; # inf/-inf/NaN aren't
}
+###############################################################################
+
sub bmul
{
# multiply two numbers -- stolen from Knuth Vol 2 pg 233
# (BINT or num_str, BINT or num_str) return BINT
- my ($self,$x,$y,$a,$p,$r) = objectify(2,@_);
- #print "$self bmul $x ",ref($x)," $y ",ref($y),"\n";
- trace(@_);
+
+ # set up parameters
+ my ($self,$x,$y,@r) = (ref($_[0]),@_);
+ # objectify is costly, so avoid it
+ if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
+ {
+ ($self,$x,$y,@r) = objectify(2,@_);
+ }
+
return $x if $x->modify('bmul');
+
return $x->bnan() if (($x->{sign} eq $nan) || ($y->{sign} eq $nan));
- mul($x,$y); # do actual math
- return $x->round($a,$p,$r,$y);
+ # inf handling
+ if (($x->{sign} =~ /^[+-]inf$/) || ($y->{sign} =~ /^[+-]inf$/))
+ {
+ return $x->bnan() if $x->is_zero() || $y->is_zero();
+ # result will always be +-inf:
+ # +inf * +/+inf => +inf, -inf * -/-inf => +inf
+ # +inf * -/-inf => -inf, -inf * +/+inf => -inf
+ return $x->binf() if ($x->{sign} =~ /^\+/ && $y->{sign} =~ /^\+/);
+ return $x->binf() if ($x->{sign} =~ /^-/ && $y->{sign} =~ /^-/);
+ return $x->binf('-');
+ }
+
+ return $upgrade->bmul($x,$upgrade->new($y),@r)
+ if defined $upgrade && !$y->isa($self);
+
+ $r[3] = $y; # no push here
+
+ $x->{sign} = $x->{sign} eq $y->{sign} ? '+' : '-'; # +1 * +1 or -1 * -1 => +
+
+ $x->{value} = $CALC->_mul($x->{value},$y->{value}); # do actual math
+ $x->{sign} = '+' if $CALC->_is_zero($x->{value}); # no -0
+
+ $x->round(@r);
+ }
+
+sub _div_inf
+ {
+ # helper function that handles +-inf cases for bdiv()/bmod() to reuse code
+ my ($self,$x,$y) = @_;
+
+ # NaN if x == NaN or y == NaN or x==y==0
+ return wantarray ? ($x->bnan(),$self->bnan()) : $x->bnan()
+ if (($x->is_nan() || $y->is_nan()) ||
+ ($x->is_zero() && $y->is_zero()));
+
+ # +-inf / +-inf == NaN, reminder also NaN
+ if (($x->{sign} =~ /^[+-]inf$/) && ($y->{sign} =~ /^[+-]inf$/))
+ {
+ return wantarray ? ($x->bnan(),$self->bnan()) : $x->bnan();
+ }
+ # x / +-inf => 0, remainder x (works even if x == 0)
+ if ($y->{sign} =~ /^[+-]inf$/)
+ {
+ my $t = $x->copy(); # bzero clobbers up $x
+ return wantarray ? ($x->bzero(),$t) : $x->bzero()
+ }
+
+ # 5 / 0 => +inf, -6 / 0 => -inf
+ # +inf / 0 = inf, inf, and -inf / 0 => -inf, -inf
+ # exception: -8 / 0 has remainder -8, not 8
+ # exception: -inf / 0 has remainder -inf, not inf
+ if ($y->is_zero())
+ {
+ # +-inf / 0 => special case for -inf
+ return wantarray ? ($x,$x->copy()) : $x if $x->is_inf();
+ if (!$x->is_zero() && !$x->is_inf())
+ {
+ my $t = $x->copy(); # binf clobbers up $x
+ return wantarray ?
+ ($x->binf($x->{sign}),$t) : $x->binf($x->{sign})
+ }
+ }
+
+ # last case: +-inf / ordinary number
+ my $sign = '+inf';
+ $sign = '-inf' if substr($x->{sign},0,1) ne $y->{sign};
+ $x->{sign} = $sign;
+ return wantarray ? ($x,$self->bzero()) : $x;
}
sub bdiv
{
# (dividend: BINT or num_str, divisor: BINT or num_str) return
# (BINT,BINT) (quo,rem) or BINT (only rem)
- trace(@_);
- my ($self,$x,$y,$a,$p,$r) = objectify(2,@_);
+
+ # set up parameters
+ my ($self,$x,$y,@r) = (ref($_[0]),@_);
+ # objectify is costly, so avoid it
+ if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
+ {
+ ($self,$x,$y,@r) = objectify(2,@_);
+ }
return $x if $x->modify('bdiv');
- # NaN?
- return wantarray ? ($x->bnan(),bnan()) : $x->bnan()
- if ($x->{sign} eq $nan || $y->{sign} eq $nan || $y->is_zero());
+ return $self->_div_inf($x,$y)
+ if (($x->{sign} !~ /^[+-]$/) || ($y->{sign} !~ /^[+-]$/) || $y->is_zero());
- # 0 / something
- return wantarray ? ($x,$self->bzero()) : $x if $x->is_zero();
-
- # Is $x in the interval [0, $y) ?
- my $cmp = acmp($x->{value},$y->{value});
- if (($cmp < 0) and ($x->{sign} eq $y->{sign}))
- {
- return $x->bzero() unless wantarray;
- my $t = $x->copy(); # make copy first, because $x->bzero() clobbers $x
- return ($x->bzero(),$t);
- }
- elsif ($cmp == 0)
- {
- # shortcut, both are the same, so set to +/- 1
- $x->_one( ($x->{sign} ne $y->{sign} ? '-' : '+') );
- return $x unless wantarray;
- return ($x,$self->bzero());
- }
+ return $upgrade->bdiv($upgrade->new($x),$upgrade->new($y),@r)
+ if defined $upgrade;
+ $r[3] = $y; # no push!
+
# calc new sign and in case $y == +/- 1, return $x
+ my $xsign = $x->{sign}; # keep
$x->{sign} = ($x->{sign} ne $y->{sign} ? '-' : '+');
- # check for / +-1 (cant use $y->is_one due to '-'
- if ((@{$y->{value}} == 1) && ($y->{value}->[0] == 1))
- {
- return wantarray ? ($x,$self->bzero()) : $x;
- }
- # call div here
- my $rem = $self->bzero();
- $rem->{sign} = $y->{sign};
- ($x->{value},$rem->{value}) = div($x->{value},$y->{value});
- # do not leave rest "-0";
- $rem->{sign} = '+' if (@{$rem->{value}} == 1) && ($rem->{value}->[0] == 0);
- if (($x->{sign} eq '-') and (!$rem->is_zero()))
- {
- $x->bdec();
- }
- $x->round($a,$p,$r,$y);
if (wantarray)
{
- $rem->round($a,$p,$r,$x,$y);
- return ($x,$y-$rem) if $x->{sign} eq '-'; # was $x,$rem
+ my $rem = $self->bzero();
+ ($x->{value},$rem->{value}) = $CALC->_div($x->{value},$y->{value});
+ $x->{sign} = '+' if $CALC->_is_zero($x->{value});
+ $rem->{_a} = $x->{_a};
+ $rem->{_p} = $x->{_p};
+ $x->round(@r);
+ if (! $CALC->_is_zero($rem->{value}))
+ {
+ $rem->{sign} = $y->{sign};
+ $rem = $y->copy()->bsub($rem) if $xsign ne $y->{sign}; # one of them '-'
+ }
+ else
+ {
+ $rem->{sign} = '+'; # dont leave -0
+ }
+ $rem->round(@r);
return ($x,$rem);
}
- return $x;
+
+ $x->{value} = $CALC->_div($x->{value},$y->{value});
+ $x->{sign} = '+' if $CALC->_is_zero($x->{value});
+
+ $x->round(@r);
}
-sub bpow
+###############################################################################
+# modulus functions
+
+sub bmod
{
+ # modulus (or remainder)
# (BINT or num_str, BINT or num_str) return BINT
- # compute power of two numbers -- stolen from Knuth Vol 2 pg 233
- # modifies first argument
- #trace(@_);
- my ($self,$x,$y,$a,$p,$r) = objectify(2,@_);
+
+ # set up parameters
+ my ($self,$x,$y,@r) = (ref($_[0]),@_);
+ # objectify is costly, so avoid it
+ if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
+ {
+ ($self,$x,$y,@r) = objectify(2,@_);
+ }
- return $x if $x->modify('bpow');
-
- return $x->bnan() if $x->{sign} eq $nan || $y->{sign} eq $nan;
- return $x->_one() if $y->is_zero();
- return $x if $x->is_one() || $y->is_one();
- if ($x->{sign} eq '-' && @{$x->{value}} == 1 && $x->{value}->[0] == 1)
- {
- # if $x == -1 and odd/even y => +1/-1
- return $y->is_odd() ? $x : $x->_set(1); # $x->babs() would work to
- # my Casio FX-5500L has here a bug, -1 ** 2 is -1, but -1 * -1 is 1 LOL
- }
- # shortcut for $x ** 2
- if ($y->{sign} eq '+' && @{$y->{value}} == 1 && $y->{value}->[0] == 2)
- {
- return $x->bmul($x)->bround($a,$p,$r);
- }
- # 1 ** -y => 1 / (1**y), so do test for negative $y after above's clause
- return $x->bnan() if $y->{sign} eq '-';
- return $x if $x->is_zero(); # 0**y => 0 (if not y <= 0)
-
- # tels: 10**x is special (actually 100**x etc is special, too) but not here
- #if ((@{$x->{value}} == 1) && ($x->{value}->[0] == 10))
- # {
- # # 10**2
- # my $yi = int($y); my $yi5 = int($yi/5);
- # $x->{value} = [];
- # my $v = $x->{value};
- # if ($yi5 > 0)
- # {
- # # $x->{value}->[$yi5-1] = 0; # pre-padd array (no use)
- # for (my $i = 0; $i < $yi5; $i++)
- # {
- # $v->[$i] = 0;
- # }
- # }
- # push @{$v}, int( '1'.'0' x ($yi % 5));
- # if ($x->{sign} eq '-')
- # {
- # $x->{sign} = $y->is_odd() ? '-' : '+'; # -10**2 = 100, -10**3 = -1000
- # }
- # return $x;
- # }
-
- # based on the assumption that shifting in base 10 is fast, and that bpow()
- # works faster if numbers are small: we count trailing zeros (this step is
- # O(1)..O(N), but in case of O(N) we save much more time), stripping them
- # out of the multiplication, and add $count * $y zeros afterwards:
- # 300 ** 3 == 300*300*300 == 3*3*3 . '0' x 2 * 3 == 27 . '0' x 6
- my $zeros = $x->_trailing_zeros();
- if ($zeros > 0)
- {
- $x->brsft($zeros,10); # remove zeros
- $x->bpow($y); # recursion (will not branch into here again)
- $zeros = $y * $zeros; # real number of zeros to add
- $x->blsft($zeros,10);
- return $x;
+ return $x if $x->modify('bmod');
+ $r[3] = $y; # no push!
+ if (($x->{sign} !~ /^[+-]$/) || ($y->{sign} !~ /^[+-]$/) || $y->is_zero())
+ {
+ my ($d,$r) = $self->_div_inf($x,$y);
+ $x->{sign} = $r->{sign};
+ $x->{value} = $r->{value};
+ return $x->round(@r);
}
- my $pow2 = $self->_one();
- my $y1 = $class->new($y);
- my ($res);
- while (!$y1->is_one())
+ # calc new sign and in case $y == +/- 1, return $x
+ $x->{value} = $CALC->_mod($x->{value},$y->{value});
+ if (!$CALC->_is_zero($x->{value}))
+ {
+ $x->{value} = $CALC->_sub($y->{value},$x->{value},1) # $y-$x
+ if ($x->{sign} ne $y->{sign});
+ $x->{sign} = $y->{sign};
+ }
+ else
{
- #print "bpow: p2: $pow2 x: $x y: $y1 r: $res\n";
- #print "len ",$x->length(),"\n";
- ($y1,$res)=&bdiv($y1,2);
- if (!$res->is_zero()) { &bmul($pow2,$x); }
- if (!$y1->is_zero()) { &bmul($x,$x); }
+ $x->{sign} = '+'; # dont leave -0
}
- #print "bpow: e p2: $pow2 x: $x y: $y1 r: $res\n";
- &bmul($x,$pow2) if (!$pow2->is_one());
- #print "bpow: e p2: $pow2 x: $x y: $y1 r: $res\n";
- return $x->round($a,$p,$r);
+ $x->round(@r);
}
-sub blsft
+sub bmodinv
{
- # (BINT or num_str, BINT or num_str) return BINT
- # compute x << y, base n, y >= 0
- my ($self,$x,$y,$n) = objectify(2,@_);
-
- return $x if $x->modify('blsft');
- return $x->bnan() if ($x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/);
-
- $n = 2 if !defined $n; return $x if $n == 0;
- return $x->bnan() if $n < 0 || $y->{sign} eq '-';
- if ($n != 10)
+ # Modular inverse. given a number which is (hopefully) relatively
+ # prime to the modulus, calculate its inverse using Euclid's
+ # alogrithm. If the number is not relatively prime to the modulus
+ # (i.e. their gcd is not one) then NaN is returned.
+
+ # set up parameters
+ my ($self,$x,$y,@r) = (undef,@_);
+ # objectify is costly, so avoid it
+ if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
{
- $x->bmul( $self->bpow($n, $y) );
- }
- else
- {
- # shortcut (faster) for shifting by 10) since we are in base 10eX
- # multiples of 5:
- my $src = scalar @{$x->{value}}; # source
- my $len = $y->numify(); # shift-len as normal int
- my $rem = $len % 5; # reminder to shift
- my $dst = $src + int($len/5); # destination
-
- my $v = $x->{value}; # speed-up
- my $vd; # further speedup
- #print "src $src:",$v->[$src]||0," dst $dst:",$v->[$dst]||0," rem $rem\n";
- $v->[$src] = 0; # avoid first ||0 for speed
- while ($src >= 0)
- {
- $vd = $v->[$src]; $vd = '00000'.$vd;
- #print "s $src d $dst '$vd' ";
- $vd = substr($vd,-5+$rem,5-$rem);
- #print "'$vd' ";
- $vd .= $src > 0 ? substr('00000'.$v->[$src-1],-5,$rem) : '0' x $rem;
- #print "'$vd' ";
- $vd = substr($vd,-5,5) if length($vd) > 5;
- #print "'$vd'\n";
- $v->[$dst] = int($vd);
- $dst--; $src--;
- }
- # set lowest parts to 0
- while ($dst >= 0) { $v->[$dst--] = 0; }
- # fix spurios last zero element
- splice @$v,-1 if $v->[-1] == 0;
- #print "elems: "; my $i = 0;
- #foreach (reverse @$v) { print "$i $_ "; $i++; } print "\n";
- # old way: $x->bmul( $self->bpow($n, $y) );
+ ($self,$x,$y,@r) = objectify(2,@_);
}
- return $x;
+
+ return $x if $x->modify('bmodinv');
+
+ return $x->bnan()
+ if ($y->{sign} ne '+' # -, NaN, +inf, -inf
+ || $x->is_zero() # or num == 0
+ || $x->{sign} !~ /^[+-]$/ # or num NaN, inf, -inf
+ );
+
+ # put least residue into $x if $x was negative, and thus make it positive
+ $x->bmod($y) if $x->{sign} eq '-';
+
+ my $sign;
+ ($x->{value},$sign) = $CALC->_modinv($x->{value},$y->{value});
+ return $x->bnan() if !defined $x->{value}; # in case no GCD found
+ return $x if !defined $sign; # already real result
+ $x->{sign} = $sign; # flip/flop see below
+ $x->bmod($y); # calc real result
+ $x;
}
-sub brsft
+sub bmodpow
{
- # (BINT or num_str, BINT or num_str) return BINT
- # compute x >> y, base n, y >= 0
- my ($self,$x,$y,$n) = objectify(2,@_);
+ # takes a very large number to a very large exponent in a given very
+ # large modulus, quickly, thanks to binary exponentation. supports
+ # negative exponents.
+ my ($self,$num,$exp,$mod,@r) = objectify(3,@_);
- return $x if $x->modify('brsft');
- return $x->bnan() if ($x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/);
+ return $num if $num->modify('bmodpow');
- $n = 2 if !defined $n; return $x->bnan() if $n <= 0 || $y->{sign} eq '-';
- if ($n != 10)
+ # check modulus for valid values
+ return $num->bnan() if ($mod->{sign} ne '+' # NaN, - , -inf, +inf
+ || $mod->is_zero());
+
+ # check exponent for valid values
+ if ($exp->{sign} =~ /\w/)
{
- scalar bdiv($x, $self->bpow($n, $y));
+ # i.e., if it's NaN, +inf, or -inf...
+ return $num->bnan();
}
- else
- {
- # shortcut (faster) for shifting by 10)
- # multiples of 5:
- my $dst = 0; # destination
- my $src = $y->numify(); # as normal int
- my $rem = $src % 5; # reminder to shift
- $src = int($src / 5); # source
- my $len = scalar @{$x->{value}} - $src; # elems to go
- my $v = $x->{value}; # speed-up
- if ($rem == 0)
+
+ $num->bmodinv ($mod) if ($exp->{sign} eq '-');
+
+ # check num for valid values (also NaN if there was no inverse but $exp < 0)
+ return $num->bnan() if $num->{sign} !~ /^[+-]$/;
+
+ # $mod is positive, sign on $exp is ignored, result also positive
+ $num->{value} = $CALC->_modpow($num->{value},$exp->{value},$mod->{value});
+ $num;
+ }
+
+###############################################################################
+
+sub bfac
+ {
+ # (BINT or num_str, BINT or num_str) return BINT
+ # compute factorial number from $x, modify $x in place
+ my ($self,$x,@r) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
+
+ return $x if $x->modify('bfac') || $x->{sign} eq '+inf'; # inf => inf
+ return $x->bnan() if $x->{sign} ne '+'; # NaN, <0 etc => NaN
+
+ $x->{value} = $CALC->_fac($x->{value});
+ $x->round(@r);
+ }
+
+sub bpow
+ {
+ # (BINT or num_str, BINT or num_str) return BINT
+ # compute power of two numbers -- stolen from Knuth Vol 2 pg 233
+ # modifies first argument
+
+ # set up parameters
+ my ($self,$x,$y,@r) = (ref($_[0]),@_);
+ # objectify is costly, so avoid it
+ if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
+ {
+ ($self,$x,$y,@r) = objectify(2,@_);
+ }
+
+ return $x if $x->modify('bpow');
+
+ return $x->bnan() if $x->{sign} eq $nan || $y->{sign} eq $nan;
+
+ # inf handling
+ if (($x->{sign} =~ /^[+-]inf$/) || ($y->{sign} =~ /^[+-]inf$/))
+ {
+ if (($x->{sign} =~ /^[+-]inf$/) && ($y->{sign} =~ /^[+-]inf$/))
{
- splice (@$v,0,$src); # even faster, 38.4 => 39.3
+ # +-inf ** +-inf
+ return $x->bnan();
}
- else
+ # +-inf ** Y
+ if ($x->{sign} =~ /^[+-]inf/)
+ {
+ # +inf ** 0 => NaN
+ return $x->bnan() if $y->is_zero();
+ # -inf ** -1 => 1/inf => 0
+ return $x->bzero() if $y->is_one('-') && $x->is_negative();
+
+ # +inf ** Y => inf
+ return $x if $x->{sign} eq '+inf';
+
+ # -inf ** Y => -inf if Y is odd
+ return $x if $y->is_odd();
+ return $x->babs();
+ }
+ # X ** +-inf
+
+ # 1 ** +inf => 1
+ return $x if $x->is_one();
+
+ # 0 ** inf => 0
+ return $x if $x->is_zero() && $y->{sign} =~ /^[+]/;
+
+ # 0 ** -inf => inf
+ return $x->binf() if $x->is_zero();
+
+ # -1 ** -inf => NaN
+ return $x->bnan() if $x->is_one('-') && $y->{sign} =~ /^[-]/;
+
+ # -X ** -inf => 0
+ return $x->bzero() if $x->{sign} eq '-' && $y->{sign} =~ /^[-]/;
+
+ # -1 ** inf => NaN
+ return $x->bnan() if $x->{sign} eq '-';
+
+ # X ** inf => inf
+ return $x->binf() if $y->{sign} =~ /^[+]/;
+ # X ** -inf => 0
+ return $x->bzero();
+ }
+
+ return $upgrade->bpow($upgrade->new($x),$y,@r)
+ if defined $upgrade && !$y->isa($self);
+
+ $r[3] = $y; # no push!
+
+ # cases 0 ** Y, X ** 0, X ** 1, 1 ** Y are handled by Calc or Emu
+
+ my $new_sign = '+';
+ $new_sign = $y->is_odd() ? '-' : '+' if ($x->{sign} ne '+');
+
+ # 0 ** -7 => ( 1 / (0 ** 7)) => 1 / 0 => +inf
+ return $x->binf()
+ if $y->{sign} eq '-' && $x->{sign} eq '+' && $CALC->_is_zero($x->{value});
+ # 1 ** -y => 1 / (1 ** |y|)
+ # so do test for negative $y after above's clause
+ return $x->bnan() if $y->{sign} eq '-' && !$CALC->_is_one($x->{value});
+
+ $x->{value} = $CALC->_pow($x->{value},$y->{value});
+ $x->{sign} = $new_sign;
+ $x->{sign} = '+' if $CALC->_is_zero($y->{value});
+ $x->round(@r);
+ }
+
+sub blsft
+ {
+ # (BINT or num_str, BINT or num_str) return BINT
+ # compute x << y, base n, y >= 0
+
+ # set up parameters
+ my ($self,$x,$y,$n,@r) = (ref($_[0]),@_);
+ # objectify is costly, so avoid it
+ if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
+ {
+ ($self,$x,$y,$n,@r) = objectify(2,@_);
+ }
+
+ return $x if $x->modify('blsft');
+ return $x->bnan() if ($x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/);
+ return $x->round(@r) if $y->is_zero();
+
+ $n = 2 if !defined $n; return $x->bnan() if $n <= 0 || $y->{sign} eq '-';
+
+ $x->{value} = $CALC->_lsft($x->{value},$y->{value},$n);
+ $x->round(@r);
+ }
+
+sub brsft
+ {
+ # (BINT or num_str, BINT or num_str) return BINT
+ # compute x >> y, base n, y >= 0
+
+ # set up parameters
+ my ($self,$x,$y,$n,@r) = (ref($_[0]),@_);
+ # objectify is costly, so avoid it
+ if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
+ {
+ ($self,$x,$y,$n,@r) = objectify(2,@_);
+ }
+
+ return $x if $x->modify('brsft');
+ return $x->bnan() if ($x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/);
+ return $x->round(@r) if $y->is_zero();
+ return $x->bzero(@r) if $x->is_zero(); # 0 => 0
+
+ $n = 2 if !defined $n; return $x->bnan() if $n <= 0 || $y->{sign} eq '-';
+
+ # this only works for negative numbers when shifting in base 2
+ if (($x->{sign} eq '-') && ($n == 2))
+ {
+ return $x->round(@r) if $x->is_one('-'); # -1 => -1
+ if (!$y->is_one())
{
- my $vd;
- $v->[scalar @$v] = 0; # avoid || 0 test inside loop
- while ($dst < $len)
+ # although this is O(N*N) in calc (as_bin!) it is O(N) in Pari et al
+ # but perhaps there is a better emulation for two's complement shift...
+ # if $y != 1, we must simulate it by doing:
+ # convert to bin, flip all bits, shift, and be done
+ $x->binc(); # -3 => -2
+ my $bin = $x->as_bin();
+ $bin =~ s/^-0b//; # strip '-0b' prefix
+ $bin =~ tr/10/01/; # flip bits
+ # now shift
+ if (CORE::length($bin) <= $y)
{
- $vd = '00000'.$v->[$src];
- #print "$dst $src '$vd' ";
- $vd = substr($vd,-5,5-$rem);
- #print "'$vd' ";
- $src++;
- $vd = substr('00000'.$v->[$src],-$rem,$rem) . $vd;
- #print "'$vd1' ";
- #print "'$vd'\n";
- $vd = substr($vd,-5,5) if length($vd) > 5;
- $v->[$dst] = int($vd);
- $dst++;
- }
- splice (@$v,$dst) if $dst > 0; # kill left-over array elems
- pop @$v if $v->[-1] == 0; # kill last element
- } # else rem == 0
- # old way: scalar bdiv($x, $self->bpow($n, $y));
+ $bin = '0'; # shifting to far right creates -1
+ # 0, because later increment makes
+ # that 1, attached '-' makes it '-1'
+ # because -1 >> x == -1 !
+ }
+ else
+ {
+ $bin =~ s/.{$y}$//; # cut off at the right side
+ $bin = '1' . $bin; # extend left side by one dummy '1'
+ $bin =~ tr/10/01/; # flip bits back
+ }
+ my $res = $self->new('0b'.$bin); # add prefix and convert back
+ $res->binc(); # remember to increment
+ $x->{value} = $res->{value}; # take over value
+ return $x->round(@r); # we are done now, magic, isn't?
+ }
+ # x < 0, n == 2, y == 1
+ $x->bdec(); # n == 2, but $y == 1: this fixes it
}
- return $x;
+
+ $x->{value} = $CALC->_rsft($x->{value},$y->{value},$n);
+ $x->round(@r);
}
sub band
{
#(BINT or num_str, BINT or num_str) return BINT
# compute x & y
- trace(@_);
- my ($self,$x,$y) = objectify(2,@_);
+
+ # set up parameters
+ my ($self,$x,$y,@r) = (ref($_[0]),@_);
+ # objectify is costly, so avoid it
+ if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
+ {
+ ($self,$x,$y,@r) = objectify(2,@_);
+ }
return $x if $x->modify('band');
+ $r[3] = $y; # no push!
+
return $x->bnan() if ($x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/);
- return $x->bzero() if $y->is_zero();
- my $r = $self->bzero(); my $m = new Math::BigInt 1; my ($xr,$yr);
- my $x10000 = new Math::BigInt (0x10000);
- my $y1 = copy(ref($x),$y); # make copy
- while (!$x->is_zero() && !$y1->is_zero())
+
+ my $sx = $x->{sign} eq '+' ? 1 : -1;
+ my $sy = $y->{sign} eq '+' ? 1 : -1;
+
+ if ($sx == 1 && $sy == 1)
{
- ($x, $xr) = bdiv($x, $x10000);
- ($y1, $yr) = bdiv($y1, $x10000);
- $r->badd( bmul( new Math::BigInt ( $xr->numify() & $yr->numify()), $m ));
- $m->bmul($x10000);
+ $x->{value} = $CALC->_and($x->{value},$y->{value});
+ return $x->round(@r);
}
- $x = $r;
+
+ if ($CAN{signed_and})
+ {
+ $x->{value} = $CALC->_signed_and($x->{value},$y->{value},$sx,$sy);
+ return $x->round(@r);
+ }
+
+ require $EMU_LIB;
+ __emu_band($self,$x,$y,$sx,$sy,@r);
}
sub bior
{
#(BINT or num_str, BINT or num_str) return BINT
# compute x | y
- trace(@_);
- my ($self,$x,$y) = objectify(2,@_);
+
+ # set up parameters
+ my ($self,$x,$y,@r) = (ref($_[0]),@_);
+ # objectify is costly, so avoid it
+ if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
+ {
+ ($self,$x,$y,@r) = objectify(2,@_);
+ }
return $x if $x->modify('bior');
+ $r[3] = $y; # no push!
return $x->bnan() if ($x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/);
- return $x if $y->is_zero();
- my $r = $self->bzero(); my $m = new Math::BigInt 1; my ($xr,$yr);
- my $x10000 = new Math::BigInt (0x10000);
- my $y1 = copy(ref($x),$y); # make copy
- while (!$x->is_zero() || !$y1->is_zero())
+
+ my $sx = $x->{sign} eq '+' ? 1 : -1;
+ my $sy = $y->{sign} eq '+' ? 1 : -1;
+
+ # the sign of X follows the sign of X, e.g. sign of Y irrelevant for bior()
+
+ # don't use lib for negative values
+ if ($sx == 1 && $sy == 1)
+ {
+ $x->{value} = $CALC->_or($x->{value},$y->{value});
+ return $x->round(@r);
+ }
+
+ # if lib can do negative values, let it handle this
+ if ($CAN{signed_or})
{
- ($x, $xr) = bdiv($x,$x10000);
- ($y1, $yr) = bdiv($y1,$x10000);
- $r->badd( bmul( new Math::BigInt ( $xr->numify() | $yr->numify()), $m ));
- $m->bmul($x10000);
+ $x->{value} = $CALC->_signed_or($x->{value},$y->{value},$sx,$sy);
+ return $x->round(@r);
}
- $x = $r;
+
+ require $EMU_LIB;
+ __emu_bior($self,$x,$y,$sx,$sy,@r);
}
sub bxor
{
#(BINT or num_str, BINT or num_str) return BINT
# compute x ^ y
- my ($self,$x,$y) = objectify(2,@_);
+
+ # set up parameters
+ my ($self,$x,$y,@r) = (ref($_[0]),@_);
+ # objectify is costly, so avoid it
+ if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
+ {
+ ($self,$x,$y,@r) = objectify(2,@_);
+ }
return $x if $x->modify('bxor');
+ $r[3] = $y; # no push!
+
+ return $x->bnan() if ($x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/);
+
+ my $sx = $x->{sign} eq '+' ? 1 : -1;
+ my $sy = $y->{sign} eq '+' ? 1 : -1;
- return $x->bnan() if ($x->{sign} eq $nan || $y->{sign} eq $nan);
- return $x if $y->is_zero();
- return $x->bzero() if $x == $y; # shortcut
- my $r = $self->bzero(); my $m = new Math::BigInt 1; my ($xr,$yr);
- my $x10000 = new Math::BigInt (0x10000);
- my $y1 = copy(ref($x),$y); # make copy
- while (!$x->is_zero() || !$y1->is_zero())
+ # don't use lib for negative values
+ if ($sx == 1 && $sy == 1)
{
- ($x, $xr) = bdiv($x, $x10000);
- ($y1, $yr) = bdiv($y1, $x10000);
- $r->badd( bmul( new Math::BigInt ( $xr->numify() ^ $yr->numify()), $m ));
- $m->bmul($x10000);
+ $x->{value} = $CALC->_xor($x->{value},$y->{value});
+ return $x->round(@r);
}
- $x = $r;
+
+ # if lib can do negative values, let it handle this
+ if ($CAN{signed_xor})
+ {
+ $x->{value} = $CALC->_signed_xor($x->{value},$y->{value},$sx,$sy);
+ return $x->round(@r);
+ }
+
+ require $EMU_LIB;
+ __emu_bxor($self,$x,$y,$sx,$sy,@r);
}
sub length
{
- my ($self,$x) = objectify(1,@_);
+ my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
- return (_digits($x->{value}), 0) if wantarray;
- _digits($x->{value});
+ my $e = $CALC->_len($x->{value});
+ wantarray ? ($e,0) : $e;
}
sub digit
{
- # return the nth digit, negative values count backward
- my $x = shift;
- my $n = shift || 0;
-
- my $len = $x->length();
+ # return the nth decimal digit, negative values count backward, 0 is right
+ my ($self,$x,$n) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
- $n = $len+$n if $n < 0; # -1 last, -2 second-to-last
- $n = abs($n); # if negatives are to big
- $len--; $n = $len if $n > $len; # n to big?
-
- my $elem = int($n / 5); # which array element
- my $digit = $n % 5; # which digit in this element
- $elem = '0000'.$x->{value}->[$elem]; # get element padded with 0's
- return substr($elem,-$digit-1,1);
+ $n = $n->numify() if ref($n);
+ $CALC->_digit($x->{value},$n||0);
}
sub _trailing_zeros
{
- # return the amount of trailing zeros in $x
+ # return the amount of trailing zeros in $x (as scalar)
my $x = shift;
$x = $class->new($x) unless ref $x;
- return 0 if $x->is_zero() || $x->is_nan();
- # check each array elem in _m for having 0 at end as long as elem == 0
- # Upon finding a elem != 0, stop
- my $zeros = 0; my $elem;
- foreach my $e (@{$x->{value}})
- {
- if ($e != 0)
- {
- $elem = "$e"; # preserve x
- $elem =~ s/.*?(0*$)/$1/; # strip anything not zero
- $zeros *= 5; # elems * 5
- $zeros += CORE::length($elem); # count trailing zeros
- last; # early out
- }
- $zeros ++; # real else branch: 50% slower!
- }
- return $zeros;
+ return 0 if $x->{sign} !~ /^[+-]$/; # NaN, inf, -inf etc
+
+ $CALC->_zeros($x->{value}); # must handle odd values, 0 etc
}
sub bsqrt
{
- my ($self,$x) = objectify(1,@_);
+ # calculate square root of $x
+ my ($self,$x,@r) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
- return $x->bnan() if $x->{sign} =~ /\-|$nan/; # -x or NaN => NaN
- return $x->bzero() if $x->is_zero(); # 0 => 0
- return $x if $x == 1; # 1 => 1
+ return $x if $x->modify('bsqrt');
- my $y = $x->copy(); # give us one more digit accur.
- my $l = int($x->length()/2);
-
- $x->bzero();
- $x->binc(); # keep ref($x), but modify it
- $x *= 10 ** $l;
+ return $x->bnan() if $x->{sign} !~ /^\+/; # -x or -inf or NaN => NaN
+ return $x if $x->{sign} eq '+inf'; # sqrt(+inf) == inf
+
+ return $upgrade->bsqrt($x,@r) if defined $upgrade;
+
+ $x->{value} = $CALC->_sqrt($x->{value});
+ $x->round(@r);
+ }
+
+sub broot
+ {
+ # calculate $y'th root of $x
+
+ # set up parameters
+ my ($self,$x,$y,@r) = (ref($_[0]),@_);
- # print "x: $y guess $x\n";
+ $y = $self->new(2) unless defined $y;
- my $last = $self->bzero();
- while ($last != $x)
+ # objectify is costly, so avoid it
+ if ((!ref($x)) || (ref($x) ne ref($y)))
{
- $last = $x;
- $x += $y / $x;
- $x /= 2;
+ ($self,$x,$y,@r) = objectify(2,$self || $class,@_);
}
- return $x;
+
+ return $x if $x->modify('broot');
+
+ # NaN handling: $x ** 1/0, x or y NaN, or y inf/-inf or y == 0
+ return $x->bnan() if $x->{sign} !~ /^\+/ || $y->is_zero() ||
+ $y->{sign} !~ /^\+$/;
+
+ return $x->round(@r)
+ if $x->is_zero() || $x->is_one() || $x->is_inf() || $y->is_one();
+
+ return $upgrade->new($x)->broot($upgrade->new($y),@r) if defined $upgrade;
+
+ $x->{value} = $CALC->_root($x->{value},$y->{value});
+ $x->round(@r);
}
sub exponent
{
# return a copy of the exponent (here always 0, NaN or 1 for $m == 0)
- my ($self,$x) = objectify(1,@_);
+ my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
- return bnan() if $x->is_nan();
- my $e = $class->bzero();
- return $e->binc() if $x->is_zero();
- $e += $x->_trailing_zeros();
- return $e;
+ if ($x->{sign} !~ /^[+-]$/)
+ {
+ my $s = $x->{sign}; $s =~ s/^[+-]//; # NaN, -inf,+inf => NaN or inf
+ return $self->new($s);
+ }
+ return $self->bone() if $x->is_zero();
+
+ $self->new($x->_trailing_zeros());
}
sub mantissa
{
- # return a copy of the mantissa (here always $self)
- my ($self,$x) = objectify(1,@_);
+ # return the mantissa (compatible to Math::BigFloat, e.g. reduced)
+ my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
- return bnan() if $x->is_nan();
- my $m = $x->copy();
- # that's inefficient
+ if ($x->{sign} !~ /^[+-]$/)
+ {
+ # for NaN, +inf, -inf: keep the sign
+ return $self->new($x->{sign});
+ }
+ my $m = $x->copy(); delete $m->{_p}; delete $m->{_a};
+ # that's a bit inefficient:
my $zeros = $m->_trailing_zeros();
- $m /= 10 ** $zeros if $zeros != 0;
- return $m;
+ $m->brsft($zeros,10) if $zeros != 0;
+ $m;
}
sub parts
{
- # return a copy of both the exponent and the mantissa (here 0 and self)
- my $self = shift;
- $self = $class->new($self) unless ref $self;
+ # return a copy of both the exponent and the mantissa
+ my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
- return ($self->mantissa(),$self->exponent());
+ ($x->mantissa(),$x->exponent());
}
##############################################################################
sub bfround
{
# precision: round to the $Nth digit left (+$n) or right (-$n) from the '.'
- # $n == 0 => round to integer
- my $x = shift; $x = $class->new($x) unless ref $x;
- my ($scale,$mode) = $x->_scale_p($precision,$rnd_mode,@_);
- return $x if !defined $scale; # no-op
+ # $n == 0 || $n == 1 => round to integer
+ my $x = shift; my $self = ref($x) || $x; $x = $self->new($x) unless ref $x;
+
+ my ($scale,$mode) = $x->_scale_p(@_);
+
+ return $x if !defined $scale || $x->modify('bfround'); # no-op
# no-op for BigInts if $n <= 0
- return $x if $scale <= 0;
+ $x->bround( $x->length()-$scale, $mode) if $scale > 0;
- $x->bround( $x->length()-$scale, $mode);
+ delete $x->{_a}; # delete to save memory
+ $x->{_p} = $scale; # store new _p
+ $x;
}
sub _scan_for_nonzero
{
- my $x = shift;
- my $pad = shift;
+ # internal, used by bround() to scan for non-zeros after a '5'
+ my ($x,$pad,$xs,$len) = @_;
- my $len = $x->length();
- return 0 if $len == 1; # '5' is trailed by invisible zeros
+ return 0 if $len == 1; # "5" is trailed by invisible zeros
my $follow = $pad - 1;
return 0 if $follow > $len || $follow < 1;
- #print "checking $x $r\n";
- # old, slow way checking string for non-zero characters
- my $r = substr ("$x",-$follow);
- return 1 if $r =~ /[^0]/; return 0;
-
- # faster way checking array contents; it is actually not faster (even in a
- # rounding-only-shoutout, so I leave the simpler code in)
- #my $rem = $follow % 5; my $div = $follow / 5; my $v = $x->{value};
- # pad with zeros and extract
- #print "last part : ",'00000'.$v->[$div]," $rem = '";
- #print substr('00000'.$v->[$div],-$rem,5),"'\n";
- #my $r1 = substr ('00000'.$v->[$div],-$rem,5);
- #print "$r1\n";
- #return 1 if $r1 =~ /[^0]/;
- #
- #for (my $j = $div-1; $j >= 0; $j --)
- # {
- # #print "part $v->[$j]\n";
- # return 1 if $v->[$j] != 0;
- # }
- #return 0;
+
+ # use the string form to check whether only '0's follow or not
+ substr ($xs,-$follow) =~ /[^0]/ ? 1 : 0;
}
sub fround
{
- # to make life easier for switch between MBF and MBI (autoload fxxx()
- # like MBF does for bxxx()?)
- my $x = shift;
- return $x->bround(@_);
+ # Exists to make life easier for switch between MBF and MBI (should we
+ # autoload fxxx() like MBF does for bxxx()?)
+ my $x = shift; $x = $class->new($x) unless ref $x;
+ $x->bround(@_);
}
sub bround
# no-op for $n == 0
# and overwrite the rest with 0's, return normalized number
# do not return $x->bnorm(), but $x
+
my $x = shift; $x = $class->new($x) unless ref $x;
- my ($scale,$mode) = $x->_scale_a($accuracy,$rnd_mode,@_);
- return $x if !defined $scale; # no-op
+ my ($scale,$mode) = $x->_scale_a(@_);
+ return $x if !defined $scale || $x->modify('bround'); # no-op
- # print "MBI round: $x to $scale $mode\n";
- # -scale means what? tom? hullo? -$scale needed by MBF round, but what for?
- return $x if $x->is_nan() || $x->is_zero() || $scale == 0;
+ if ($x->is_zero() || $scale == 0)
+ {
+ $x->{_a} = $scale if !defined $x->{_a} || $x->{_a} > $scale; # 3 > 2
+ return $x;
+ }
+ return $x if $x->{sign} !~ /^[+-]$/; # inf, NaN
# we have fewer digits than we want to scale to
my $len = $x->length();
- # print "$len $scale\n";
- return $x if $len < abs($scale);
+ # convert $scale to a scalar in case it is an object (put's a limit on the
+ # number length, but this would already limited by memory constraints), makes
+ # it faster
+ $scale = $scale->numify() if ref ($scale);
+
+ # scale < 0, but > -len (not >=!)
+ if (($scale < 0 && $scale < -$len-1) || ($scale >= $len))
+ {
+ $x->{_a} = $scale if !defined $x->{_a} || $x->{_a} > $scale; # 3 > 2
+ return $x;
+ }
# count of 0's to pad, from left (+) or right (-): 9 - +6 => 3, or |-6| => 6
my ($pad,$digit_round,$digit_after);
$pad = $len - $scale;
- $pad = abs($scale)+1 if $scale < 0;
- $digit_round = '0'; $digit_round = $x->digit($pad) if $pad < $len;
- $digit_after = '0'; $digit_after = $x->digit($pad-1) if $pad > 0;
- # print "r $x: pos:$pad l:$len s:$scale r:$digit_round a:$digit_after m: $mode\n";
+ $pad = abs($scale-1) if $scale < 0;
+
+ # do not use digit(), it is very costly for binary => decimal
+ # getting the entire string is also costly, but we need to do it only once
+ my $xs = $CALC->_str($x->{value});
+ my $pl = -$pad-1;
+
+ # pad: 123: 0 => -1, at 1 => -2, at 2 => -3, at 3 => -4
+ # pad+1: 123: 0 => 0, at 1 => -1, at 2 => -2, at 3 => -3
+ $digit_round = '0'; $digit_round = substr($xs,$pl,1) if $pad <= $len;
+ $pl++; $pl ++ if $pad >= $len;
+ $digit_after = '0'; $digit_after = substr($xs,$pl,1) if $pad > 0;
# in case of 01234 we round down, for 6789 up, and only in case 5 we look
# closer at the remaining digits of the original $x, remember decision
($digit_after =~ /[01234]/) || # round down anyway,
# 6789 => round up
($digit_after eq '5') && # not 5000...0000
- ($x->_scan_for_nonzero($pad) == 0) &&
+ ($x->_scan_for_nonzero($pad,$xs,$len) == 0) &&
(
($mode eq 'even') && ($digit_round =~ /[24680]/) ||
($mode eq 'odd') && ($digit_round =~ /[13579]/) ||
($mode eq '-inf') && ($x->{sign} eq '+') ||
($mode eq 'zero') # round down if zero, sign adjusted below
);
- # allow rounding one place left of mantissa
- #print "$pad $len $scale\n";
- # this is triggering warnings, and buggy for $scale < 0
- #if (-$scale != $len)
- {
- # split mantissa at $scale and then pad with zeros
- my $s5 = int($pad / 5);
- my $i = 0;
- while ($i < $s5)
- {
- $x->{value}->[$i++] = 0; # replace with 5 x 0
- }
- $x->{value}->[$s5] = '00000'.$x->{value}->[$s5]; # pad with 0
- my $rem = $pad % 5; # so much left over
- if ($rem > 0)
+ my $put_back = 0; # not yet modified
+
+ if (($pad > 0) && ($pad <= $len))
+ {
+ substr($xs,-$pad,$pad) = '0' x $pad; # replace with '00...'
+ $put_back = 1; # need to put back
+ }
+ elsif ($pad > $len)
+ {
+ $x->bzero(); # round to '0'
+ }
+
+ if ($round_up) # what gave test above?
+ {
+ $put_back = 1; # need to put back
+ $pad = $len, $xs = '0' x $pad if $scale < 0; # tlr: whack 0.51=>1.0
+
+ # we modify directly the string variant instead of creating a number and
+ # adding it, since that is faster (we already have the string)
+ my $c = 0; $pad ++; # for $pad == $len case
+ while ($pad <= $len)
{
- #print "remainder $rem\n";
- #print "elem $x->{value}->[$s5]\n";
- substr($x->{value}->[$s5],-$rem,$rem) = '0' x $rem; # stamp w/ '0'
+ $c = substr($xs,-$pad,1) + 1; $c = '0' if $c eq '10';
+ substr($xs,-$pad,1) = $c; $pad++;
+ last if $c != 0; # no overflow => early out
}
- $x->{value}->[$s5] = int ($x->{value}->[$s5]); # str '05' => int '5'
+ $xs = '1'.$xs if $c == 0;
+
}
- if ($round_up) # what gave test above?
+ $x->{value} = $CALC->_new($xs) if $put_back == 1; # put back, if needed
+
+ $x->{_a} = $scale if $scale >= 0;
+ if ($scale < 0)
{
- $pad = $len if $scale < 0; # tlr: whack 0.51=>1.0
- # modify $x in place, undef, undef to avoid rounding
- $x->badd( Math::BigInt->new($x->{sign}.'1'.'0'x$pad),
- undef,undef );
- # str creation much faster than 10 ** something
+ $x->{_a} = $len+$scale;
+ $x->{_a} = 0 if $scale < -$len;
}
$x;
}
sub bfloor
{
- # return integer less or equal then number, since it is already integer,
- # always returns $self
- my ($self,$x,$a,$p,$r) = objectify(1,@_);
+ # return integer less or equal then number; no-op since it's already integer
+ my ($self,$x,@r) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
- # not needed: return $x if $x->modify('bfloor');
-
- return $x->round($a,$p,$r);
+ $x->round(@r);
}
sub bceil
{
- # return integer greater or equal then number, since it is already integer,
- # always returns $self
- my ($self,$x,$a,$p,$r) = objectify(1,@_);
-
- # not needed: return $x if $x->modify('bceil');
+ # return integer greater or equal then number; no-op since it's already int
+ my ($self,$x,@r) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
- return $x->round($a,$p,$r);
+ $x->round(@r);
}
-##############################################################################
-# private stuff (internal use only)
-
-sub trace
+sub as_number
{
- # print out a number without using bstr (avoid deep recurse) for trace/debug
- return unless $trace;
-
- my ($package,$file,$line,$sub) = caller(1);
- print "'$sub' called from '$package' line $line:\n ";
-
- foreach my $x (@_)
- {
- if (!defined $x)
- {
- print "undef, "; next;
- }
- if (!ref($x))
- {
- print "'$x' "; next;
- }
- next if (ref($x) ne "HASH");
- print "$x->{sign} ";
- foreach (@{$x->{value}})
- {
- print "$_ ";
- }
- print ", ";
- }
- print "\n";
+ # An object might be asked to return itself as bigint on certain overloaded
+ # operations, this does exactly this, so that sub classes can simple inherit
+ # it or override with their own integer conversion routine.
+ $_[0]->copy();
}
-sub _set
+sub as_hex
{
- # internal set routine to set X fast to an integer value < [+-]100000
- my $self = shift;
- my $wanted = shift || 0;
+ # return as hex string, with prefixed 0x
+ my $x = shift; $x = $class->new($x) if !ref($x);
- $self->{sign} = $nan, return if $wanted !~ /^[+-]?[0-9]+$/;
- $self->{sign} = '-'; $self->{sign} = '+' if $wanted >= 0;
- $self->{value} = [ abs($wanted) ];
- return $self;
- }
+ return $x->bstr() if $x->{sign} !~ /^[+-]$/; # inf, nan etc
-sub _one
- {
- # internal speedup, set argument to 1, or create a +/- 1
- my $self = shift;
- my $x = $self->bzero(); $x->{value} = [ 1 ]; $x->{sign} = shift || '+'; $x;
+ my $s = '';
+ $s = $x->{sign} if $x->{sign} eq '-';
+ $s . $CALC->_as_hex($x->{value});
}
-sub _swap
+sub as_bin
{
- # Overload will swap params if first one is no object ref so that the first
- # one is always an object ref. In this case, third param is true.
- # This routine is to overcome the effect of scalar,$object creating an object
- # of the class of this package, instead of the second param $object. This
- # happens inside overload, when the overload section of this package is
- # inherited by sub classes.
- # For overload cases (and this is used only there), we need to preserve the
- # args, hence the copy().
- # You can override this method in a subclass, the overload section will call
- # $object->_swap() to make sure it arrives at the proper subclass, with some
- # exceptions like '+' and '-'.
+ # return as binary string, with prefixed 0b
+ my $x = shift; $x = $class->new($x) if !ref($x);
- # object, (object|scalar) => preserve first and make copy
- # scalar, object => swapped, re-swap and create new from first
- # (using class of second object, not $class!!)
- my $self = shift; # for override in subclass
- #print "swap $self 0:$_[0] 1:$_[1] 2:$_[2]\n";
- if ($_[2])
- {
- my $c = ref ($_[0]) || $class; # fallback $class should not happen
- return ( $c->new($_[1]), $_[0] );
- }
- else
- {
- return ( $_[0]->copy(), $_[1] );
- }
+ return $x->bstr() if $x->{sign} !~ /^[+-]$/; # inf, nan etc
+
+ my $s = ''; $s = $x->{sign} if $x->{sign} eq '-';
+ return $s . $CALC->_as_bin($x->{value});
}
+##############################################################################
+# private stuff (internal use only)
+
sub objectify
{
# check for strings, if yes, return objects instead
# the first argument is number of args objectify() should look at it will
# return $count+1 elements, the first will be a classname. This is because
# overloaded '""' calls bstr($object,undef,undef) and this would result in
- # useless objects beeing created and thrown away. So we cannot simple loop
+ # useless objects being created and thrown away. So we cannot simple loop
# over @_. If the given count is 0, all arguments will be used.
# If the second arg is a ref, use it as class.
# $class,1,2. (We can not take '1' as class ;o)
# badd($class,1) is not supported (it should, eventually, try to add undef)
# currently it tries 'Math::BigInt' + 1, which will not work.
-
- trace(@_);
+
+ # some shortcut for the common cases
+ # $x->unary_op();
+ return (ref($_[1]),$_[1]) if (@_ == 2) && ($_[0]||0 == 1) && ref($_[1]);
+
my $count = abs(shift || 0);
- #print caller(),"\n";
-
- my @a; # resulting array
+ my (@a,$k,$d); # resulting array, temp, and downgrade
if (ref $_[0])
{
# okay, got object as first
{
# nope, got 1,2 (Class->xxx(1) => Class,1 and not supported)
$a[0] = $class;
- #print "@_\n"; sleep(1);
$a[0] = shift if $_[0] =~ /^[A-Z].*::/; # classname as first?
}
- #print caller(),"\n";
- # print "Now in objectify, my class is today $a[0]\n";
- my $k;
+
+ no strict 'refs';
+ # disable downgrading, because Math::BigFLoat->foo('1.0','2.0') needs floats
+ if (defined ${"$a[0]::downgrade"})
+ {
+ $d = ${"$a[0]::downgrade"};
+ ${"$a[0]::downgrade"} = undef;
+ }
+
+ my $up = ${"$a[0]::upgrade"};
+ #print "Now in objectify, my class is today $a[0], count = $count\n";
if ($count == 0)
{
while (@_)
{
$k = $a[0]->new($k);
}
- elsif (ref($k) ne $a[0])
+ elsif (!defined $up && ref($k) ne $a[0])
{
# foreign object, try to convert to integer
$k->can('as_number') ? $k = $k->as_number() : $k = $a[0]->new($k);
{
while ($count > 0)
{
- #print "$count\n";
$count--;
$k = shift;
if (!ref($k))
{
$k = $a[0]->new($k);
}
- elsif (ref($k) ne $a[0])
+ elsif (!defined $up && ref($k) ne $a[0])
{
# foreign object, try to convert to integer
$k->can('as_number') ? $k = $k->as_number() : $k = $a[0]->new($k);
}
push @a,@_; # return other params, too
}
- #my $i = 0;
- #foreach (@a)
- # {
- # print "o $i $a[0]\n" if $i == 0;
- # print "o $i ",ref($_),"\n" if $i != 0; $i++;
- # }
- #print "objectify done: would return ",scalar @a," values\n";
- #print caller(1),"\n" unless wantarray;
- die "$class objectify needs list context" unless wantarray;
+ if (! wantarray)
+ {
+ require Carp; Carp::croak ("$class objectify needs list context");
+ }
+ ${"$a[0]::downgrade"} = $d;
@a;
}
+sub _register_callback
+ {
+ my ($class,$callback) = @_;
+
+ if (ref($callback) ne 'CODE')
+ {
+ require Carp;
+ Carp::croak ("$callback is not a coderef");
+ }
+ $CALLBACKS{$class} = $callback;
+ }
+
sub import
{
my $self = shift;
- #print "import $self @_\n";
- for ( my $i = 0; $i < @_ ; $i++ )
+
+ $IMPORT++; # remember we did import()
+ my @a; my $l = scalar @_;
+ for ( my $i = 0; $i < $l ; $i++ )
{
- if ( $_[$i] eq ':constant' )
+ if ($_[$i] eq ':constant')
+ {
+ # this causes overlord er load to step in
+ overload::constant
+ integer => sub { $self->new(shift) },
+ binary => sub { $self->new(shift) };
+ }
+ elsif ($_[$i] eq 'upgrade')
+ {
+ # this causes upgrading
+ $upgrade = $_[$i+1]; # or undef to disable
+ $i++;
+ }
+ elsif ($_[$i] =~ /^lib$/i)
+ {
+ # this causes a different low lib to take care...
+ $CALC = $_[$i+1] || '';
+ $i++;
+ }
+ else
{
- # this rest causes overlord er load to step in
- overload::constant integer => sub { $self->new(shift) };
- splice @_, $i, 1; last;
+ push @a, $_[$i];
}
}
# any non :constant stuff is handled by our parent, Exporter
- # even if @_ is empty, to give it a chance
- #$self->SUPER::import(@_); # does not work
- $self->export_to_level(1,$self,@_); # need this instead
- }
-
-sub _internal
- {
- # (ref to self, ref to string) return ref to num_array
- # Convert a number from string format to internal base 100000 format.
- # Assumes normalized value as input.
- my ($s,$d) = @_;
- my $il = CORE::length($$d)-1;
- # these leaves '00000' instead of int 0 and will be corrected after any op
- $s->{value} = [ reverse(unpack("a" . ($il%5+1) . ("a5" x ($il/5)), $$d)) ];
- $s;
- }
-
-sub _strip_zeros
- {
- # internal normalization function that strips leading zeros from the array
- # args: ref to array
- #trace(@_);
- my $s = shift;
+ if (@a > 0)
+ {
+ require Exporter;
- my $cnt = scalar @$s; # get count of parts
- my $i = $cnt-1;
- #print "strip: cnt $cnt i $i\n";
- # '0', '3', '4', '0', '0',
- # 0 1 2 3 4
- # cnt = 5, i = 4
- # i = 4
- # i = 3
- # => fcnt = cnt - i (5-2 => 3, cnt => 5-1 = 4, throw away from 4th pos)
- # >= 1: skip first part (this can be zero)
- while ($i > 0) { last if $s->[$i] != 0; $i--; }
- $i++; splice @$s,$i if ($i < $cnt); # $i cant be 0
- return $s;
- }
-
-sub _from_hex
- {
- # convert a (ref to) big hex string to BigInt, return undef for error
- my $hs = shift;
-
- my $x = Math::BigInt->bzero();
- return $x->bnan() if $$hs !~ /^[\-\+]?0x[0-9A-Fa-f]+$/;
-
- my $mul = Math::BigInt->bzero(); $mul++;
- my $x65536 = Math::BigInt->new(65536);
+ $self->SUPER::import(@a); # need it for subclasses
+ $self->export_to_level(1,$self,@a); # need it for MBF
+ }
- my $len = CORE::length($$hs)-2; my $sign = '+';
- if ($$hs =~ /^\-/)
+ # try to load core math lib
+ my @c = split /\s*,\s*/,$CALC;
+ foreach (@c)
+ {
+ $_ =~ tr/a-zA-Z0-9://cd; # limit to sane characters
+ }
+ push @c, 'FastCalc', 'Calc'; # if all fail, try these
+ $CALC = ''; # signal error
+ foreach my $lib (@c)
{
- $sign = '-'; $len--;
+ next if ($lib || '') eq '';
+ $lib = 'Math::BigInt::'.$lib if $lib !~ /^Math::BigInt/i;
+ $lib =~ s/\.pm$//;
+ if ($] < 5.006)
+ {
+ # Perl < 5.6.0 dies with "out of memory!" when eval("") and ':constant' is
+ # used in the same script, or eval("") inside import().
+ my @parts = split /::/, $lib; # Math::BigInt => Math BigInt
+ my $file = pop @parts; $file .= '.pm'; # BigInt => BigInt.pm
+ require File::Spec;
+ $file = File::Spec->catfile (@parts, $file);
+ eval { require "$file"; $lib->import( @c ); }
+ }
+ else
+ {
+ eval "use $lib qw/@c/;";
+ }
+ if ($@ eq '')
+ {
+ my $ok = 1;
+ # loaded it ok, see if the api_version() is high enough
+ if ($lib->can('api_version') && $lib->api_version() >= 1.0)
+ {
+ $ok = 0;
+ # api_version matches, check if it really provides anything we need
+ for my $method (qw/
+ one two ten
+ str num
+ add mul div sub dec inc
+ acmp len digit is_one is_zero is_even is_odd
+ is_two is_ten
+ new copy check from_hex from_bin as_hex as_bin zeros
+ rsft lsft xor and or
+ mod sqrt root fac pow modinv modpow log_int gcd
+ /)
+ {
+ if (!$lib->can("_$method"))
+ {
+ if (($WARN{$lib}||0) < 2)
+ {
+ require Carp;
+ Carp::carp ("$lib is missing method '_$method'");
+ $WARN{$lib} = 1; # still warn about the lib
+ }
+ $ok++; last;
+ }
+ }
+ }
+ if ($ok == 0)
+ {
+ $CALC = $lib;
+ last; # found a usable one, break
+ }
+ else
+ {
+ if (($WARN{$lib}||0) < 2)
+ {
+ my $ver = eval "\$$lib\::VERSION" || 'unknown';
+ require Carp;
+ Carp::carp ("Cannot load outdated $lib v$ver, please upgrade");
+ $WARN{$lib} = 2; # never warn again
+ }
+ }
+ }
}
- $len = int($len/4); # 4-digit parts, w/o '0x'
- my $val; my $i = -4;
- while ($len >= 0)
+ if ($CALC eq '')
{
- $val = substr($$hs,$i,4);
- $val =~ s/^[\-\+]?0x// if $len == 0; # for last part only because
- $val = hex($val); # hex does not like wrong chars
- # print "$val ",substr($$hs,$i,4),"\n";
- $i -= 4; $len --;
- $x += $mul * $val if $val != 0;
- $mul *= $x65536 if $len >= 0; # skip last mul
+ require Carp;
+ Carp::croak ("Couldn't load any math lib, not even 'Calc.pm'");
}
- $x->{sign} = $sign if !$x->is_zero();
- return $x;
- }
-sub _from_bin
+ # notify callbacks
+ foreach my $class (keys %CALLBACKS)
+ {
+ &{$CALLBACKS{$class}}($CALC);
+ }
+
+ # Fill $CAN with the results of $CALC->can(...) for emulating lower math lib
+ # functions
+
+ %CAN = ();
+ for my $method (qw/ signed_and signed_or signed_xor /)
+ {
+ $CAN{$method} = $CALC->can("_$method") ? 1 : 0;
+ }
+
+ # import done
+ }
+
+sub __from_hex
+ {
+ # internal
+ # convert a (ref to) big hex string to BigInt, return undef for error
+ my $hs = shift;
+
+ my $x = Math::BigInt->bzero();
+
+ # strip underscores
+ $hs =~ s/([0-9a-fA-F])_([0-9a-fA-F])/$1$2/g;
+ $hs =~ s/([0-9a-fA-F])_([0-9a-fA-F])/$1$2/g;
+
+ return $x->bnan() if $hs !~ /^[\-\+]?0x[0-9A-Fa-f]+$/;
+
+ my $sign = '+'; $sign = '-' if $hs =~ /^-/;
+
+ $hs =~ s/^[+-]//; # strip sign
+ $x->{value} = $CALC->_from_hex($hs);
+ $x->{sign} = $sign unless $CALC->_is_zero($x->{value}); # no '-0'
+ $x;
+ }
+
+sub __from_bin
{
+ # internal
# convert a (ref to) big binary string to BigInt, return undef for error
my $bs = shift;
my $x = Math::BigInt->bzero();
- return $x->bnan() if $$bs !~ /^[\-\+]?0b[01]+$/;
+ # strip underscores
+ $bs =~ s/([01])_([01])/$1$2/g;
+ $bs =~ s/([01])_([01])/$1$2/g;
+ return $x->bnan() if $bs !~ /^[+-]?0b[01]+$/;
- my $mul = Math::BigInt->bzero(); $mul++;
- my $x256 = Math::BigInt->new(256);
+ my $sign = '+'; $sign = '-' if $bs =~ /^\-/;
+ $bs =~ s/^[+-]//; # strip sign
- my $len = CORE::length($$bs)-2; my $sign = '+';
- if ($$bs =~ /^\-/)
- {
- $sign = '-'; $len--;
- }
- $len = int($len/8); # 8-digit parts, w/o '0b'
- my $val; my $i = -8;
- while ($len >= 0)
- {
- $val = substr($$bs,$i,8);
- $val =~ s/^[\-\+]?0b// if $len == 0; # for last part only
- #$val = oct('0b'.$val); # does not work on Perl prior 5.6.0
- $val = ('0' x (8-CORE::length($val))).$val if CORE::length($val) < 8;
- $val = ord(pack('B8',$val));
- # print "$val ",substr($$bs,$i,16),"\n";
- $i -= 8; $len --;
- $x += $mul * $val if $val != 0;
- $mul *= $x256 if $len >= 0; # skip last mul
- }
- $x->{sign} = $sign if !$x->is_zero();
- return $x;
+ $x->{value} = $CALC->_from_bin($bs);
+ $x->{sign} = $sign unless $CALC->_is_zero($x->{value}); # no '-0'
+ $x;
}
sub _split
{
- # (ref to num_str) return num_str
- # internal, take apart a string and return the pieces
+ # input: num_str; output: undef for invalid or
+ # (\$mantissa_sign,\$mantissa_value,\$mantissa_fraction,\$exp_sign,\$exp_value)
+ # Internal, take apart a string and return the pieces.
+ # Strip leading/trailing whitespace, leading zeros, underscore and reject
+ # invalid input.
my $x = shift;
- # pre-parse input
- $$x =~ s/^\s+//g; # strip white space at front
- $$x =~ s/\s+$//g; # strip white space at end
- #$$x =~ s/\s+//g; # strip white space (no longer)
- return if $$x eq "";
+ # strip white space at front, also extranous leading zeros
+ $x =~ s/^\s*([-]?)0*([0-9])/$1$2/g; # will not strip ' .2'
+ $x =~ s/^\s+//; # but this will
+ $x =~ s/\s+$//g; # strip white space at end
- return _from_hex($x) if $$x =~ /^[\-\+]?0x/; # hex string
- return _from_bin($x) if $$x =~ /^[\-\+]?0b/; # binary string
+ # shortcut, if nothing to split, return early
+ if ($x =~ /^[+-]?\d+\z/)
+ {
+ $x =~ s/^([+-])0*([0-9])/$2/; my $sign = $1 || '+';
+ return (\$sign, \$x, \'', \'', \0);
+ }
- return if $$x !~ /^[\-\+]?\.?[0-9]/;
+ # invalid starting char?
+ return if $x !~ /^[+-]?(\.?[0-9]|0b[0-1]|0x[0-9a-fA-F])/;
- $$x =~ s/(\d)_(\d)/$1$2/g; # strip underscores between digits
- $$x =~ s/(\d)_(\d)/$1$2/g; # do twice for 1_2_3
+ return __from_hex($x) if $x =~ /^[\-\+]?0x/; # hex string
+ return __from_bin($x) if $x =~ /^[\-\+]?0b/; # binary string
+ # strip underscores between digits
+ $x =~ s/(\d)_(\d)/$1$2/g;
+ $x =~ s/(\d)_(\d)/$1$2/g; # do twice for 1_2_3
+
# some possible inputs:
# 2.1234 # 0.12 # 1 # 1E1 # 2.134E1 # 434E-10 # 1.02009E-2
- # .2 # 1_2_3.4_5_6 # 1.4E1_2_3 # 1e3 # +.2
+ # .2 # 1_2_3.4_5_6 # 1.4E1_2_3 # 1e3 # +.2 # 0e999
- #print "input: '$$x' ";
- my ($m,$e) = split /[Ee]/,$$x;
+ my ($m,$e,$last) = split /[Ee]/,$x;
+ return if defined $last; # last defined => 1e2E3 or others
$e = '0' if !defined $e || $e eq "";
- # print "m '$m' e '$e'\n";
+
# sign,value for exponent,mantint,mantfrac
my ($es,$ev,$mis,$miv,$mfv);
# valid exponent?
if ($e =~ /^([+-]?)0*(\d+)$/) # strip leading zeros
{
$es = $1; $ev = $2;
- #print "'$m' '$e' e: $es $ev ";
# valid mantissa?
return if $m eq '.' || $m eq '';
- my ($mi,$mf) = split /\./,$m;
+ my ($mi,$mf,$lastf) = split /\./,$m;
+ return if defined $lastf; # lastf defined => 1.2.3 or others
$mi = '0' if !defined $mi;
$mi .= '0' if $mi =~ /^[\-\+]?$/;
$mf = '0' if !defined $mf || $mf eq '';
if ($mi =~ /^([+-]?)0*(\d+)$/) # strip leading zeros
{
$mis = $1||'+'; $miv = $2;
- #print "$mis $miv";
- # valid, existing fraction part of mantissa?
return unless ($mf =~ /^(\d*?)0*$/); # strip trailing zeros
$mfv = $1;
- #print " split: $mis $miv . $mfv E $es $ev\n";
+ # handle the 0e999 case here
+ $ev = 0 if $miv eq '0' && $mfv eq '';
return (\$mis,\$miv,\$mfv,\$es,\$ev);
}
}
return; # NaN, not a number
}
-sub _digits
- {
- # computer number of digits in bigint, minus the sign
- # int() because add/sub leaves sometimes strings (like '00005') instead of
- # int ('5') in this place, causing length to fail
- my $cx = shift;
+##############################################################################
+# internal calculation routines (others are in Math::BigInt::Calc etc)
+
+sub __lcm
+ {
+ # (BINT or num_str, BINT or num_str) return BINT
+ # does modify first argument
+ # LCM
+
+ my ($x,$ty) = @_;
+ return $x->bnan() if ($x->{sign} eq $nan) || ($ty->{sign} eq $nan);
+ my $method = ref($x) . '::bgcd';
+ no strict 'refs';
+ $x * $ty / &$method($x,$ty);
+ }
+
+###############################################################################
+# this method returns 0 if the object can be modified, or 1 if not.
+# We use a fast constant sub() here, to avoid costly calls. Subclasses
+# may override it with special code (f.i. Math::BigInt::Constant does so)
+
+sub modify () { 0; }
+
+1;
+__END__
+
+=pod
+
+=head1 NAME
+
+Math::BigInt - Arbitrary size integer/float math package
+
+=head1 SYNOPSIS
+
+ use Math::BigInt;
+
+ # or make it faster: install (optional) Math::BigInt::GMP
+ # and always use (it will fall back to pure Perl if the
+ # GMP library is not installed):
+
+ use Math::BigInt lib => 'GMP';
+
+ my $str = '1234567890';
+ my @values = (64,74,18);
+ my $n = 1; my $sign = '-';
+
+ # Number creation
+ $x = Math::BigInt->new($str); # defaults to 0
+ $y = $x->copy(); # make a true copy
+ $nan = Math::BigInt->bnan(); # create a NotANumber
+ $zero = Math::BigInt->bzero(); # create a +0
+ $inf = Math::BigInt->binf(); # create a +inf
+ $inf = Math::BigInt->binf('-'); # create a -inf
+ $one = Math::BigInt->bone(); # create a +1
+ $one = Math::BigInt->bone('-'); # create a -1
+
+ # Testing (don't modify their arguments)
+ # (return true if the condition is met, otherwise false)
+
+ $x->is_zero(); # if $x is +0
+ $x->is_nan(); # if $x is NaN
+ $x->is_one(); # if $x is +1
+ $x->is_one('-'); # if $x is -1
+ $x->is_odd(); # if $x is odd
+ $x->is_even(); # if $x is even
+ $x->is_pos(); # if $x >= 0
+ $x->is_neg(); # if $x < 0
+ $x->is_inf($sign); # if $x is +inf, or -inf (sign is default '+')
+ $x->is_int(); # if $x is an integer (not a float)
+
+ # comparing and digit/sign extraction
+ $x->bcmp($y); # compare numbers (undef,<0,=0,>0)
+ $x->bacmp($y); # compare absolutely (undef,<0,=0,>0)
+ $x->sign(); # return the sign, either +,- or NaN
+ $x->digit($n); # return the nth digit, counting from right
+ $x->digit(-$n); # return the nth digit, counting from left
+
+ # The following all modify their first argument. If you want to preserve
+ # $x, use $z = $x->copy()->bXXX($y); See under L<CAVEATS> for why this is
+ # necessary when mixing $a = $b assignments with non-overloaded math.
+
+ $x->bzero(); # set $x to 0
+ $x->bnan(); # set $x to NaN
+ $x->bone(); # set $x to +1
+ $x->bone('-'); # set $x to -1
+ $x->binf(); # set $x to inf
+ $x->binf('-'); # set $x to -inf
+
+ $x->bneg(); # negation
+ $x->babs(); # absolute value
+ $x->bnorm(); # normalize (no-op in BigInt)
+ $x->bnot(); # two's complement (bit wise not)
+ $x->binc(); # increment $x by 1
+ $x->bdec(); # decrement $x by 1
+
+ $x->badd($y); # addition (add $y to $x)
+ $x->bsub($y); # subtraction (subtract $y from $x)
+ $x->bmul($y); # multiplication (multiply $x by $y)
+ $x->bdiv($y); # divide, set $x to quotient
+ # return (quo,rem) or quo if scalar
+
+ $x->bmod($y); # modulus (x % y)
+ $x->bmodpow($exp,$mod); # modular exponentation (($num**$exp) % $mod))
+ $x->bmodinv($mod); # the inverse of $x in the given modulus $mod
+
+ $x->bpow($y); # power of arguments (x ** y)
+ $x->blsft($y); # left shift
+ $x->brsft($y); # right shift
+ $x->blsft($y,$n); # left shift, by base $n (like 10)
+ $x->brsft($y,$n); # right shift, by base $n (like 10)
+
+ $x->band($y); # bitwise and
+ $x->bior($y); # bitwise inclusive or
+ $x->bxor($y); # bitwise exclusive or
+ $x->bnot(); # bitwise not (two's complement)
+
+ $x->bsqrt(); # calculate square-root
+ $x->broot($y); # $y'th root of $x (e.g. $y == 3 => cubic root)
+ $x->bfac(); # factorial of $x (1*2*3*4*..$x)
+
+ $x->round($A,$P,$mode); # round to accuracy or precision using mode $mode
+ $x->bround($n); # accuracy: preserve $n digits
+ $x->bfround($n); # round to $nth digit, no-op for BigInts
+
+ # The following do not modify their arguments in BigInt (are no-ops),
+ # but do so in BigFloat:
+
+ $x->bfloor(); # return integer less or equal than $x
+ $x->bceil(); # return integer greater or equal than $x
+
+ # The following do not modify their arguments:
+
+ # greatest common divisor (no OO style)
+ my $gcd = Math::BigInt::bgcd(@values);
+ # lowest common multiplicator (no OO style)
+ my $lcm = Math::BigInt::blcm(@values);
+
+ $x->length(); # return number of digits in number
+ ($xl,$f) = $x->length(); # length of number and length of fraction part,
+ # latter is always 0 digits long for BigInts
+
+ $x->exponent(); # return exponent as BigInt
+ $x->mantissa(); # return (signed) mantissa as BigInt
+ $x->parts(); # return (mantissa,exponent) as BigInt
+ $x->copy(); # make a true copy of $x (unlike $y = $x;)
+ $x->as_int(); # return as BigInt (in BigInt: same as copy())
+ $x->numify(); # return as scalar (might overflow!)
+
+ # conversation to string (do not modify their argument)
+ $x->bstr(); # normalized string (e.g. '3')
+ $x->bsstr(); # norm. string in scientific notation (e.g. '3E0')
+ $x->as_hex(); # as signed hexadecimal string with prefixed 0x
+ $x->as_bin(); # as signed binary string with prefixed 0b
+
+
+ # precision and accuracy (see section about rounding for more)
+ $x->precision(); # return P of $x (or global, if P of $x undef)
+ $x->precision($n); # set P of $x to $n
+ $x->accuracy(); # return A of $x (or global, if A of $x undef)
+ $x->accuracy($n); # set A $x to $n
+
+ # Global methods
+ Math::BigInt->precision(); # get/set global P for all BigInt objects
+ Math::BigInt->accuracy(); # get/set global A for all BigInt objects
+ Math::BigInt->round_mode(); # get/set global round mode, one of
+ # 'even', 'odd', '+inf', '-inf', 'zero' or 'trunc'
+ Math::BigInt->config(); # return hash containing configuration
+
+=head1 DESCRIPTION
+
+All operators (including basic math operations) are overloaded if you
+declare your big integers as
+
+ $i = new Math::BigInt '123_456_789_123_456_789';
+
+Operations with overloaded operators preserve the arguments which is
+exactly what you expect.
+
+=over 2
+
+=item Input
+
+Input values to these routines may be any string, that looks like a number
+and results in an integer, including hexadecimal and binary numbers.
+
+Scalars holding numbers may also be passed, but note that non-integer numbers
+may already have lost precision due to the conversation to float. Quote
+your input if you want BigInt to see all the digits:
+
+ $x = Math::BigInt->new(12345678890123456789); # bad
+ $x = Math::BigInt->new('12345678901234567890'); # good
+
+You can include one underscore between any two digits.
+
+This means integer values like 1.01E2 or even 1000E-2 are also accepted.
+Non-integer values result in NaN.
+
+Currently, Math::BigInt::new() defaults to 0, while Math::BigInt::new('')
+results in 'NaN'. This might change in the future, so use always the following
+explicit forms to get a zero or NaN:
+
+ $zero = Math::BigInt->bzero();
+ $nan = Math::BigInt->bnan();
+
+C<bnorm()> on a BigInt object is now effectively a no-op, since the numbers
+are always stored in normalized form. If passed a string, creates a BigInt
+object from the input.
+
+=item Output
+
+Output values are BigInt objects (normalized), except for the methods which
+return a string (see L<SYNOPSIS>).
+
+Some routines (C<is_odd()>, C<is_even()>, C<is_zero()>, C<is_one()>,
+C<is_nan()>, etc.) return true or false, while others (C<bcmp()>, C<bacmp()>)
+return either undef (if NaN is involved), <0, 0 or >0 and are suited for sort.
+
+=back
+
+=head1 METHODS
+
+Each of the methods below (except config(), accuracy() and precision())
+accepts three additional parameters. These arguments C<$A>, C<$P> and C<$R>
+are C<accuracy>, C<precision> and C<round_mode>. Please see the section about
+L<ACCURACY and PRECISION> for more information.
+
+=head2 config
+
+ use Data::Dumper;
+
+ print Dumper ( Math::BigInt->config() );
+ print Math::BigInt->config()->{lib},"\n";
+
+Returns a hash containing the configuration, e.g. the version number, lib
+loaded etc. The following hash keys are currently filled in with the
+appropriate information.
+
+ key Description
+ Example
+ ============================================================
+ lib Name of the low-level math library
+ Math::BigInt::Calc
+ lib_version Version of low-level math library (see 'lib')
+ 0.30
+ class The class name of config() you just called
+ Math::BigInt
+ upgrade To which class math operations might be upgraded
+ Math::BigFloat
+ downgrade To which class math operations might be downgraded
+ undef
+ precision Global precision
+ undef
+ accuracy Global accuracy
+ undef
+ round_mode Global round mode
+ even
+ version version number of the class you used
+ 1.61
+ div_scale Fallback accuracy for div
+ 40
+ trap_nan If true, traps creation of NaN via croak()
+ 1
+ trap_inf If true, traps creation of +inf/-inf via croak()
+ 1
+
+The following values can be set by passing C<config()> a reference to a hash:
+
+ trap_inf trap_nan
+ upgrade downgrade precision accuracy round_mode div_scale
+
+Example:
+
+ $new_cfg = Math::BigInt->config( { trap_inf => 1, precision => 5 } );
+
+=head2 accuracy
+
+ $x->accuracy(5); # local for $x
+ CLASS->accuracy(5); # global for all members of CLASS
+ # Note: This also applies to new()!
+
+ $A = $x->accuracy(); # read out accuracy that affects $x
+ $A = CLASS->accuracy(); # read out global accuracy
+
+Set or get the global or local accuracy, aka how many significant digits the
+results have. If you set a global accuracy, then this also applies to new()!
+
+Warning! The accuracy I<sticks>, e.g. once you created a number under the
+influence of C<< CLASS->accuracy($A) >>, all results from math operations with
+that number will also be rounded.
+
+In most cases, you should probably round the results explicitly using one of
+L<round()>, L<bround()> or L<bfround()> or by passing the desired accuracy
+to the math operation as additional parameter:
+
+ my $x = Math::BigInt->new(30000);
+ my $y = Math::BigInt->new(7);
+ print scalar $x->copy()->bdiv($y, 2); # print 4300
+ print scalar $x->copy()->bdiv($y)->bround(2); # print 4300
+
+Please see the section about L<ACCURACY AND PRECISION> for further details.
+
+Value must be greater than zero. Pass an undef value to disable it:
+
+ $x->accuracy(undef);
+ Math::BigInt->accuracy(undef);
+
+Returns the current accuracy. For C<$x->accuracy()> it will return either the
+local accuracy, or if not defined, the global. This means the return value
+represents the accuracy that will be in effect for $x:
+
+ $y = Math::BigInt->new(1234567); # unrounded
+ print Math::BigInt->accuracy(4),"\n"; # set 4, print 4
+ $x = Math::BigInt->new(123456); # $x will be automatically rounded!
+ print "$x $y\n"; # '123500 1234567'
+ print $x->accuracy(),"\n"; # will be 4
+ print $y->accuracy(),"\n"; # also 4, since global is 4
+ print Math::BigInt->accuracy(5),"\n"; # set to 5, print 5
+ print $x->accuracy(),"\n"; # still 4
+ print $y->accuracy(),"\n"; # 5, since global is 5
+
+Note: Works also for subclasses like Math::BigFloat. Each class has it's own
+globals separated from Math::BigInt, but it is possible to subclass
+Math::BigInt and make the globals of the subclass aliases to the ones from
+Math::BigInt.
+
+=head2 precision
+
+ $x->precision(-2); # local for $x, round at the second digit right of the dot
+ $x->precision(2); # ditto, round at the second digit left of the dot
+
+ CLASS->precision(5); # Global for all members of CLASS
+ # This also applies to new()!
+ CLASS->precision(-5); # ditto
+
+ $P = CLASS->precision(); # read out global precision
+ $P = $x->precision(); # read out precision that affects $x
+
+Note: You probably want to use L<accuracy()> instead. With L<accuracy> you
+set the number of digits each result should have, with L<precision> you
+set the place where to round!
+
+C<precision()> sets or gets the global or local precision, aka at which digit
+before or after the dot to round all results. A set global precision also
+applies to all newly created numbers!
+
+In Math::BigInt, passing a negative number precision has no effect since no
+numbers have digits after the dot. In L<Math::BigFloat>, it will round all
+results to P digits after the dot.
+
+Please see the section about L<ACCURACY AND PRECISION> for further details.
+
+Pass an undef value to disable it:
+
+ $x->precision(undef);
+ Math::BigInt->precision(undef);
+
+Returns the current precision. For C<$x->precision()> it will return either the
+local precision of $x, or if not defined, the global. This means the return
+value represents the prevision that will be in effect for $x:
+
+ $y = Math::BigInt->new(1234567); # unrounded
+ print Math::BigInt->precision(4),"\n"; # set 4, print 4
+ $x = Math::BigInt->new(123456); # will be automatically rounded
+ print $x; # print "120000"!
+
+Note: Works also for subclasses like L<Math::BigFloat>. Each class has its
+own globals separated from Math::BigInt, but it is possible to subclass
+Math::BigInt and make the globals of the subclass aliases to the ones from
+Math::BigInt.
+
+=head2 brsft
+
+ $x->brsft($y,$n);
+
+Shifts $x right by $y in base $n. Default is base 2, used are usually 10 and
+2, but others work, too.
+
+Right shifting usually amounts to dividing $x by $n ** $y and truncating the
+result:
+
+
+ $x = Math::BigInt->new(10);
+ $x->brsft(1); # same as $x >> 1: 5
+ $x = Math::BigInt->new(1234);
+ $x->brsft(2,10); # result 12
+
+There is one exception, and that is base 2 with negative $x:
+
+
+ $x = Math::BigInt->new(-5);
+ print $x->brsft(1);
+
+This will print -3, not -2 (as it would if you divide -5 by 2 and truncate the
+result).
+
+=head2 new
+
+ $x = Math::BigInt->new($str,$A,$P,$R);
+
+Creates a new BigInt object from a scalar or another BigInt object. The
+input is accepted as decimal, hex (with leading '0x') or binary (with leading
+'0b').
+
+See L<Input> for more info on accepted input formats.
+
+=head2 bnan
+
+ $x = Math::BigInt->bnan();
+
+Creates a new BigInt object representing NaN (Not A Number).
+If used on an object, it will set it to NaN:
+
+ $x->bnan();
+
+=head2 bzero
+
+ $x = Math::BigInt->bzero();
+
+Creates a new BigInt object representing zero.
+If used on an object, it will set it to zero:
+
+ $x->bzero();
+
+=head2 binf
+
+ $x = Math::BigInt->binf($sign);
+
+Creates a new BigInt object representing infinity. The optional argument is
+either '-' or '+', indicating whether you want infinity or minus infinity.
+If used on an object, it will set it to infinity:
+
+ $x->binf();
+ $x->binf('-');
+
+=head2 bone
+
+ $x = Math::BigInt->binf($sign);
+
+Creates a new BigInt object representing one. The optional argument is
+either '-' or '+', indicating whether you want one or minus one.
+If used on an object, it will set it to one:
+
+ $x->bone(); # +1
+ $x->bone('-'); # -1
+
+=head2 is_one()/is_zero()/is_nan()/is_inf()
+
+
+ $x->is_zero(); # true if arg is +0
+ $x->is_nan(); # true if arg is NaN
+ $x->is_one(); # true if arg is +1
+ $x->is_one('-'); # true if arg is -1
+ $x->is_inf(); # true if +inf
+ $x->is_inf('-'); # true if -inf (sign is default '+')
+
+These methods all test the BigInt for being one specific value and return
+true or false depending on the input. These are faster than doing something
+like:
+
+ if ($x == 0)
+
+=head2 is_pos()/is_neg()
+
+ $x->is_pos(); # true if > 0
+ $x->is_neg(); # true if < 0
+
+The methods return true if the argument is positive or negative, respectively.
+C<NaN> is neither positive nor negative, while C<+inf> counts as positive, and
+C<-inf> is negative. A C<zero> is neither positive nor negative.
+
+These methods are only testing the sign, and not the value.
+
+C<is_positive()> and C<is_negative()> are aliases to C<is_pos()> and
+C<is_neg()>, respectively. C<is_positive()> and C<is_negative()> were
+introduced in v1.36, while C<is_pos()> and C<is_neg()> were only introduced
+in v1.68.
+
+=head2 is_odd()/is_even()/is_int()
+
+ $x->is_odd(); # true if odd, false for even
+ $x->is_even(); # true if even, false for odd
+ $x->is_int(); # true if $x is an integer
+
+The return true when the argument satisfies the condition. C<NaN>, C<+inf>,
+C<-inf> are not integers and are neither odd nor even.
+
+In BigInt, all numbers except C<NaN>, C<+inf> and C<-inf> are integers.
+
+=head2 bcmp
+
+ $x->bcmp($y);
+
+Compares $x with $y and takes the sign into account.
+Returns -1, 0, 1 or undef.
+
+=head2 bacmp
+
+ $x->bacmp($y);
+
+Compares $x with $y while ignoring their. Returns -1, 0, 1 or undef.
+
+=head2 sign
+
+ $x->sign();
+
+Return the sign, of $x, meaning either C<+>, C<->, C<-inf>, C<+inf> or NaN.
+
+If you want $x to have a certain sign, use one of the following methods:
+
+ $x->babs(); # '+'
+ $x->babs()->bneg(); # '-'
+ $x->bnan(); # 'NaN'
+ $x->binf(); # '+inf'
+ $x->binf('-'); # '-inf'
+
+=head2 digit
+
+ $x->digit($n); # return the nth digit, counting from right
+
+If C<$n> is negative, returns the digit counting from left.
+
+=head2 bneg
+
+ $x->bneg();
+
+Negate the number, e.g. change the sign between '+' and '-', or between '+inf'
+and '-inf', respectively. Does nothing for NaN or zero.
+
+=head2 babs
+
+ $x->babs();
+
+Set the number to it's absolute value, e.g. change the sign from '-' to '+'
+and from '-inf' to '+inf', respectively. Does nothing for NaN or positive
+numbers.
+
+=head2 bnorm
+
+ $x->bnorm(); # normalize (no-op)
+
+=head2 bnot
+
+ $x->bnot();
+
+Two's complement (bit wise not). This is equivalent to
+
+ $x->binc()->bneg();
+
+but faster.
+
+=head2 binc
+
+ $x->binc(); # increment x by 1
+
+=head2 bdec
+
+ $x->bdec(); # decrement x by 1
+
+=head2 badd
+
+ $x->badd($y); # addition (add $y to $x)
+
+=head2 bsub
+
+ $x->bsub($y); # subtraction (subtract $y from $x)
+
+=head2 bmul
+
+ $x->bmul($y); # multiplication (multiply $x by $y)
+
+=head2 bdiv
+
+ $x->bdiv($y); # divide, set $x to quotient
+ # return (quo,rem) or quo if scalar
+
+=head2 bmod
+
+ $x->bmod($y); # modulus (x % y)
+
+=head2 bmodinv
+
+ num->bmodinv($mod); # modular inverse
+
+Returns the inverse of C<$num> in the given modulus C<$mod>. 'C<NaN>' is
+returned unless C<$num> is relatively prime to C<$mod>, i.e. unless
+C<bgcd($num, $mod)==1>.
+
+=head2 bmodpow
+
+ $num->bmodpow($exp,$mod); # modular exponentation
+ # ($num**$exp % $mod)
+
+Returns the value of C<$num> taken to the power C<$exp> in the modulus
+C<$mod> using binary exponentation. C<bmodpow> is far superior to
+writing
+
+ $num ** $exp % $mod
+
+because it is much faster - it reduces internal variables into
+the modulus whenever possible, so it operates on smaller numbers.
+
+C<bmodpow> also supports negative exponents.
+
+ bmodpow($num, -1, $mod)
+
+is exactly equivalent to
+
+ bmodinv($num, $mod)
+
+=head2 bpow
+
+ $x->bpow($y); # power of arguments (x ** y)
+
+=head2 blsft
+
+ $x->blsft($y); # left shift
+ $x->blsft($y,$n); # left shift, in base $n (like 10)
+
+=head2 brsft
+
+ $x->brsft($y); # right shift
+ $x->brsft($y,$n); # right shift, in base $n (like 10)
+
+=head2 band
+
+ $x->band($y); # bitwise and
+
+=head2 bior
+
+ $x->bior($y); # bitwise inclusive or
+
+=head2 bxor
+
+ $x->bxor($y); # bitwise exclusive or
+
+=head2 bnot
+
+ $x->bnot(); # bitwise not (two's complement)
+
+=head2 bsqrt
+
+ $x->bsqrt(); # calculate square-root
+
+=head2 bfac
+
+ $x->bfac(); # factorial of $x (1*2*3*4*..$x)
+
+=head2 round
+
+ $x->round($A,$P,$round_mode);
+
+Round $x to accuracy C<$A> or precision C<$P> using the round mode
+C<$round_mode>.
+
+=head2 bround
+
+ $x->bround($N); # accuracy: preserve $N digits
+
+=head2 bfround
+
+ $x->bfround($N); # round to $Nth digit, no-op for BigInts
+
+=head2 bfloor
+
+ $x->bfloor();
+
+Set $x to the integer less or equal than $x. This is a no-op in BigInt, but
+does change $x in BigFloat.
+
+=head2 bceil
+
+ $x->bceil();
+
+Set $x to the integer greater or equal than $x. This is a no-op in BigInt, but
+does change $x in BigFloat.
+
+=head2 bgcd
+
+ bgcd(@values); # greatest common divisor (no OO style)
+
+=head2 blcm
+
+ blcm(@values); # lowest common multiplicator (no OO style)
+
+head2 length
+
+ $x->length();
+ ($xl,$fl) = $x->length();
+
+Returns the number of digits in the decimal representation of the number.
+In list context, returns the length of the integer and fraction part. For
+BigInt's, the length of the fraction part will always be 0.
+
+=head2 exponent
+
+ $x->exponent();
+
+Return the exponent of $x as BigInt.
+
+=head2 mantissa
- #print "len: ",(@$cx-1)*5+CORE::length(int($cx->[-1])),"\n";
- return (@$cx-1)*5+CORE::length(int($cx->[-1]));
- }
+ $x->mantissa();
-sub as_number
- {
- # an object might be asked to return itself as bigint on certain overloaded
- # operations, this does exactly this, so that sub classes can simple inherit
- # it or override with their own integer conversion routine
- my $self = shift;
+Return the signed mantissa of $x as BigInt.
- return $self->copy();
- }
+=head2 parts
-##############################################################################
-# internal calculation routines
-
-sub acmp
- {
- # internal absolute post-normalized compare (ignore signs)
- # ref to array, ref to array, return <0, 0, >0
- # arrays must have at least on entry, this is not checked for
-
- my ($cx, $cy) = @_;
-
- #print "$cx $cy\n";
- my ($i,$a,$x,$y,$k);
- # calculate length based on digits, not parts
- $x = _digits($cx); $y = _digits($cy);
- # print "length: ",($x-$y),"\n";
- return $x-$y if ($x - $y); # if different in length
- #print "full compare\n";
- $i = 0; $a = 0;
- # first way takes 5.49 sec instead of 4.87, but has the early out advantage
- # so grep is slightly faster, but more unflexible. hm. $_ instead if $k
- # yields 5.6 instead of 5.5 sec huh?
- # manual way (abort if unequal, good for early ne)
- my $j = scalar @$cx - 1;
- while ($j >= 0)
- {
- # print "$cx->[$j] $cy->[$j] $a",$cx->[$j]-$cy->[$j],"\n";
- last if ($a = $cx->[$j] - $cy->[$j]); $j--;
- }
- return $a;
- # while it early aborts, it is even slower than the manual variant
- #grep { return $a if ($a = $_ - $cy->[$i++]); } @$cx;
- # grep way, go trough all (bad for early ne)
- #grep { $a = $_ - $cy->[$i++]; } @$cx;
- #return $a;
- }
-
-sub cmp
- {
- # post-normalized compare for internal use (honors signs)
- # ref to array, ref to array, return < 0, 0, >0
- my ($cx,$cy,$sx,$sy) = @_;
+ $x->parts(); # return (mantissa,exponent) as BigInt
- #return 0 if (is0($cx,$sx) && is0($cy,$sy));
+=head2 copy
- if ($sx eq '+')
- {
- return 1 if $sy eq '-'; # 0 check handled above
- return acmp($cx,$cy);
- }
- else
- {
- # $sx eq '-'
- return -1 if ($sy eq '+');
- return acmp($cy,$cx);
- }
- return 0; # equal
- }
+ $x->copy(); # make a true copy of $x (unlike $y = $x;)
-sub add
- {
- # (ref to int_num_array, ref to int_num_array)
- # routine to add two base 1e5 numbers
- # stolen from Knuth Vol 2 Algorithm A pg 231
- # there are separate routines to add and sub as per Kunth pg 233
- # This routine clobbers up array x, but not y.
+=head2 as_int
- my ($x,$y) = @_;
+ $x->as_int();
- # for each in Y, add Y to X and carry. If after that, something is left in
- # X, foreach in X add carry to X and then return X, carry
- # Trades one "$j++" for having to shift arrays, $j could be made integer
- # but this would impose a limit to number-length to 2**32.
- my $i; my $car = 0; my $j = 0;
- for $i (@$y)
- {
- $x->[$j] -= $BASE
- if $car = (($x->[$j] += $i + $car) >= $BASE) ? 1 : 0;
- $j++;
- }
- while ($car != 0)
- {
- $x->[$j] -= $BASE if $car = (($x->[$j] += $car) >= $BASE) ? 1 : 0; $j++;
- }
- }
+Returns $x as a BigInt (truncated towards zero). In BigInt this is the same as
+C<copy()>.
-sub sub
- {
- # (ref to int_num_array, ref to int_num_array)
- # subtract base 1e5 numbers -- stolen from Knuth Vol 2 pg 232, $x > $y
- # subtract Y from X (X is always greater/equal!) by modifiyng x in place
- my ($sx,$sy,$s) = @_;
+C<as_number()> is an alias to this method. C<as_number> was introduced in
+v1.22, while C<as_int()> was only introduced in v1.68.
+
+=head2 bstr
- my $car = 0; my $i; my $j = 0;
- if (!$s)
- {
- #print "case 2\n";
- for $i (@$sx)
- {
- last unless defined $sy->[$j] || $car;
- #print "x: $i y: $sy->[$j] c: $car\n";
- $i += $BASE if $car = (($i -= ($sy->[$j] || 0) + $car) < 0); $j++;
- #print "x: $i y: $sy->[$j-1] c: $car\n";
- }
- # might leave leading zeros, so fix that
- _strip_zeros($sx);
- return $sx;
- }
- else
- {
- #print "case 1 (swap)\n";
- for $i (@$sx)
- {
- last unless defined $sy->[$j] || $car;
- #print "$sy->[$j] $i $car => $sx->[$j]\n";
- $sy->[$j] += $BASE
- if $car = (($sy->[$j] = $i-($sy->[$j]||0) - $car) < 0);
- #print "$sy->[$j] $i $car => $sy->[$j]\n";
- $j++;
- }
- # might leave leading zeros, so fix that
- _strip_zeros($sy);
- return $sy;
- }
- }
-
-sub mul
- {
- # (BINT, BINT) return nothing
- # multiply two numbers in internal representation
- # modifies first arg, second needs not be different from first
- my ($x,$y) = @_;
-
- $x->{sign} = $x->{sign} ne $y->{sign} ? '-' : '+';
- my @prod = (); my ($prod,$car,$cty,$xi,$yi);
- my $xv = $x->{value};
- my $yv = $y->{value};
- # since multiplying $x with $x fails, make copy in this case
- $yv = [@$xv] if "$xv" eq "$yv";
- for $xi (@$xv)
- {
- $car = 0; $cty = 0;
- for $yi (@$yv)
- {
- $prod = $xi * $yi + ($prod[$cty] || 0) + $car;
- $prod[$cty++] =
- $prod - ($car = int($prod * 1e-5)) * $BASE; # see USE_MUL
- }
- $prod[$cty] += $car if $car; # need really to check for 0?
- $xi = shift @prod;
- }
- push @$xv, @prod;
- _strip_zeros($x->{value});
- # normalize (handled last to save check for $y->is_zero()
- $x->{sign} = '+' if @$xv == 1 && $xv->[0] == 0; # not is_zero due to '-'
- }
+ $x->bstr();
-sub div
- {
- # ref to array, ref to array, modify first array and return reminder if
- # in list context
- # does no longer handle sign
- my ($x,$yorg) = @_;
- my ($car,$bar,$prd,$dd,$xi,$yi,@q,$v2,$v1);
+Returns a normalized string representation of C<$x>.
- my (@d,$tmp,$q,$u2,$u1,$u0);
+=head2 bsstr
- $car = $bar = $prd = 0;
-
- my $y = [ @$yorg ];
- if (($dd = int($BASE/($y->[-1]+1))) != 1)
- {
- for $xi (@$x)
- {
- $xi = $xi * $dd + $car;
- $xi -= ($car = int($xi * $RBASE)) * $BASE; # see USE_MUL
- }
- push(@$x, $car); $car = 0;
- for $yi (@$y)
- {
- $yi = $yi * $dd + $car;
- $yi -= ($car = int($yi * $RBASE)) * $BASE; # see USE_MUL
- }
- }
- else
- {
- push(@$x, 0);
- }
- @q = (); ($v2,$v1) = @$y[-2,-1];
- $v2 = 0 unless $v2;
- while ($#$x > $#$y)
- {
- ($u2,$u1,$u0) = @$x[-3..-1];
- $u2 = 0 unless $u2;
- print "oups v1 is 0, u0: $u0 $y->[-2] $y->[-1] l ",scalar @$y,"\n"
- if $v1 == 0;
- $q = (($u0 == $v1) ? 99999 : int(($u0*$BASE+$u1)/$v1));
- --$q while ($v2*$q > ($u0*1e5+$u1-$q*$v1)*$BASE+$u2);
- if ($q)
- {
- ($car, $bar) = (0,0);
- for ($yi = 0, $xi = $#$x-$#$y-1; $yi <= $#$y; ++$yi,++$xi)
- {
- $prd = $q * $y->[$yi] + $car;
- $prd -= ($car = int($prd * $RBASE)) * $BASE; # see USE_MUL
- $x->[$xi] += 1e5 if ($bar = (($x->[$xi] -= $prd + $bar) < 0));
- }
- if ($x->[-1] < $car + $bar)
- {
- $car = 0; --$q;
- for ($yi = 0, $xi = $#$x-$#$y-1; $yi <= $#$y; ++$yi,++$xi)
- {
- $x->[$xi] -= 1e5
- if ($car = (($x->[$xi] += $y->[$yi] + $car) > $BASE));
- }
- }
- }
- pop(@$x); unshift(@q, $q);
- }
- if (wantarray)
- {
- @d = ();
- if ($dd != 1)
- {
- $car = 0;
- for $xi (reverse @$x)
- {
- $prd = $car * $BASE + $xi;
- $car = $prd - ($tmp = int($prd / $dd)) * $dd; # see USE_MUL
- unshift(@d, $tmp);
- }
- }
- else
- {
- @d = @$x;
- }
- @$x = @q;
- _strip_zeros($x);
- _strip_zeros(\@d);
- return ($x,\@d);
- }
- @$x = @q;
- _strip_zeros($x);
- return $x;
- }
+ $x->bsstr(); # normalized string in scientific notation
-sub _lcm
- {
- # (BINT or num_str, BINT or num_str) return BINT
- # does modify first argument
- # LCM
-
- my $x = shift; my $ty = shift;
- return $x->bnan() if ($x->{sign} eq $nan) || ($ty->{sign} eq $nan);
- return $x * $ty / bgcd($x,$ty);
- }
+=head2 as_hex
-sub _gcd_old
- {
- # (BINT or num_str, BINT or num_str) return BINT
- # does modify first arg
- # GCD -- Euclids algorithm E, Knuth Vol 2 pg 296
- trace(@_);
-
- my $x = shift; my $ty = $class->new(shift); # preserve y
- return $x->bnan() if ($x->{sign} eq $nan) || ($ty->{sign} eq $nan);
+ $x->as_hex(); # as signed hexadecimal string with prefixed 0x
- while (!$ty->is_zero())
- {
- ($x, $ty) = ($ty,bmod($x,$ty));
- }
- $x;
- }
+=head2 as_bin
-sub _gcd
- {
- # (BINT or num_str, BINT or num_str) return BINT
- # does not modify arguments
- # GCD -- Euclids algorithm, variant L (Lehmer), Knuth Vol 3 pg 347 ff
- # unfortunately, it is slower and also seems buggy (the A=0, B=1, C=1, D=0
- # case..)
- trace(@_);
-
- my $u = $class->new(shift); my $v = $class->new(shift); # preserve u,v
- return $u->bnan() if ($u->{sign} eq $nan) || ($v->{sign} eq $nan);
-
- $u->babs(); $v->babs(); # Euclid is valid for |u| and |v|
-
- my ($U,$V,$A,$B,$C,$D,$T,$Q); # single precision variables
- my ($t); # multiprecision variables
-
- while ($v > $BASE)
- {
- #sleep 1;
- ($u,$v) = ($v,$u) if ($u < $v); # make sure that u >= v
- #print "gcd: $u $v\n";
- # step L1, initialize
- $A = 1; $B = 0; $C = 0; $D = 1;
- $U = $u->{value}->[-1]; # leading digits of u
- $V = $v->{value}->[-1]; # leading digits of v
-
- # step L2, test quotient
- if (($V + $C != 0) && ($V + $D != 0)) # div by zero => go to L4
- {
- $Q = int(($U + $A)/($V + $C)); # quotient
- #print "L1 A=$A B=$B C=$C D=$D U=$U V=$V Q=$Q\n";
- # do L3? (div by zero => go to L4)
- while ($Q == int(($U + $B)/($V + $D)))
- {
- # step L3, emulate Euclid
- #print "L3a A=$A B=$B C=$C D=$D U=$U V=$V Q=$Q\n";
- $T = $A - $Q*$C; $A = $C; $C = $T;
- $T = $B - $Q*$D; $B = $D; $D = $T;
- $T = $U - $Q*$V; $U = $V; $V = $T;
- last if ($V + $D == 0) || ($V + $C == 0); # div by zero => L4
- $Q = int(($U + $A)/($V + $C)); # quotient for next test
- #print "L3b A=$A B=$B C=$C D=$D U=$U V=$V Q=$Q\n";
- }
- }
- # step L4, multiprecision step
- # was if ($B == 0)
- # in case A = 0, B = 1, C = 0 and D = 1, this case would simple swap u & v
- # and loop endless. Not sure why this happens, Knuth does not make a
- # remark about this special case. bug?
- if (($B == 0) || (($A == 0) && ($C == 1) && ($D == 0)))
- {
- #print "L4b1: u=$u v=$v\n";
- ($u,$v) = ($v,bmod($u,$v));
- #$t = $u % $v; $u = $v->copy(); $v = $t;
- #print "L4b12: u=$u v=$v\n";
- }
- else
- {
- #print "L4b: $u $v $A $B $C $D\n";
- $t = $A*$u + $B*$v; $v *= $D; $v += $C*$u; $u = $t;
- #print "L4b2: $u $v\n";
- }
- } # back to L1
+ $x->as_bin(); # as signed binary string with prefixed 0b
- return _gcd_old($u,$v) if $v != 1; # v too small
- return $v; # 1
- }
+=head1 ACCURACY and PRECISION
-###############################################################################
-# this method return 0 if the object can be modified, or 1 for not
-# We use a fast use constant statement here, to avoid costly calls. Subclasses
-# may override it with special code (f.i. Math::BigInt::Constant does so)
+Since version v1.33, Math::BigInt and Math::BigFloat have full support for
+accuracy and precision based rounding, both automatically after every
+operation, as well as manually.
-use constant modify => 0;
+This section describes the accuracy/precision handling in Math::Big* as it
+used to be and as it is now, complete with an explanation of all terms and
+abbreviations.
-#sub modify
-# {
-# my $self = shift;
-# my $method = shift;
-# print "original $self modify by $method\n";
-# return 0; # $self;
-# }
+Not yet implemented things (but with correct description) are marked with '!',
+things that need to be answered are marked with '?'.
-1;
-__END__
+In the next paragraph follows a short description of terms used here (because
+these may differ from terms used by others people or documentation).
-=head1 NAME
+During the rest of this document, the shortcuts A (for accuracy), P (for
+precision), F (fallback) and R (rounding mode) will be used.
-Math::BigInt - Arbitrary size integer math package
+=head2 Precision P
-=head1 SYNOPSIS
+A fixed number of digits before (positive) or after (negative)
+the decimal point. For example, 123.45 has a precision of -2. 0 means an
+integer like 123 (or 120). A precision of 2 means two digits to the left
+of the decimal point are zero, so 123 with P = 1 becomes 120. Note that
+numbers with zeros before the decimal point may have different precisions,
+because 1200 can have p = 0, 1 or 2 (depending on what the inital value
+was). It could also have p < 0, when the digits after the decimal point
+are zero.
- use Math::BigInt;
+The string output (of floating point numbers) will be padded with zeros:
+
+ Initial value P A Result String
+ ------------------------------------------------------------
+ 1234.01 -3 1000 1000
+ 1234 -2 1200 1200
+ 1234.5 -1 1230 1230
+ 1234.001 1 1234 1234.0
+ 1234.01 0 1234 1234
+ 1234.01 2 1234.01 1234.01
+ 1234.01 5 1234.01 1234.01000
- # Number creation
- $x = Math::BigInt->new($str); # defaults to 0
- $nan = Math::BigInt->bnan(); # create a NotANumber
- $zero = Math::BigInt->bzero();# create a "+0"
-
- # Testing
- $x->is_zero(); # return whether arg is zero or not
- $x->is_nan(); # return whether arg is NaN or not
- $x->is_one(); # return true if arg is +1
- $x->is_one('-'); # return true if arg is -1
- $x->is_odd(); # return true if odd, false for even
- $x->is_even(); # return true if even, false for odd
- $x->bcmp($y); # compare numbers (undef,<0,=0,>0)
- $x->bacmp($y); # compare absolutely (undef,<0,=0,>0)
- $x->sign(); # return the sign, either +,- or NaN
- $x->digit($n); # return the nth digit, counting from right
- $x->digit(-$n); # return the nth digit, counting from left
-
- # The following all modify their first argument:
-
- # set
- $x->bzero(); # set $x to 0
- $x->bnan(); # set $x to NaN
-
- $x->bneg(); # negation
- $x->babs(); # absolute value
- $x->bnorm(); # normalize (no-op)
- $x->bnot(); # two's complement (bit wise not)
- $x->binc(); # increment x by 1
- $x->bdec(); # decrement x by 1
-
- $x->badd($y); # addition (add $y to $x)
- $x->bsub($y); # subtraction (subtract $y from $x)
- $x->bmul($y); # multiplication (multiply $x by $y)
- $x->bdiv($y); # divide, set $x to quotient
- # return (quo,rem) or quo if scalar
-
- $x->bmod($y); # modulus (x % y)
- $x->bpow($y); # power of arguments (x ** y)
- $x->blsft($y); # left shift
- $x->brsft($y); # right shift
- $x->blsft($y,$n); # left shift, by base $n (like 10)
- $x->brsft($y,$n); # right shift, by base $n (like 10)
-
- $x->band($y); # bitwise and
- $x->bior($y); # bitwise inclusive or
- $x->bxor($y); # bitwise exclusive or
- $x->bnot(); # bitwise not (two's complement)
+For BigInts, no padding occurs.
- $x->bsqrt(); # calculate square-root
+=head2 Accuracy A
- $x->round($A,$P,$round_mode); # round to accuracy or precision using mode $r
- $x->bround($N); # accuracy: preserve $N digits
- $x->bfround($N); # round to $Nth digit, no-op for BigInts
+Number of significant digits. Leading zeros are not counted. A
+number may have an accuracy greater than the non-zero digits
+when there are zeros in it or trailing zeros. For example, 123.456 has
+A of 6, 10203 has 5, 123.0506 has 7, 123.450000 has 8 and 0.000123 has 3.
- # The following do not modify their arguments in BigInt, but do in BigFloat:
- $x->bfloor(); # return integer less or equal than $x
- $x->bceil(); # return integer greater or equal than $x
-
- # The following do not modify their arguments:
+The string output (of floating point numbers) will be padded with zeros:
- bgcd(@values); # greatest common divisor
- blcm(@values); # lowest common multiplicator
-
- $x->bstr(); # normalized string
- $x->bsstr(); # normalized string in scientific notation
- $x->length(); # return number of digits in number
- ($x,$f) = $x->length(); # length of number and length of fraction part
+ Initial value P A Result String
+ ------------------------------------------------------------
+ 1234.01 3 1230 1230
+ 1234.01 6 1234.01 1234.01
+ 1234.1 8 1234.1 1234.1000
- $x->exponent(); # return exponent as BigInt
- $x->mantissa(); # return mantissa as BigInt
- $x->parts(); # return (mantissa,exponent) as BigInt
+For BigInts, no padding occurs.
-=head1 DESCRIPTION
+=head2 Fallback F
-All operators (inlcuding basic math operations) are overloaded if you
-declare your big integers as
+When both A and P are undefined, this is used as a fallback accuracy when
+dividing numbers.
- $i = new Math::BigInt '123_456_789_123_456_789';
+=head2 Rounding mode R
-Operations with overloaded operators preserve the arguments which is
-exactly what you expect.
+When rounding a number, different 'styles' or 'kinds'
+of rounding are possible. (Note that random rounding, as in
+Math::Round, is not implemented.)
=over 2
-=item Canonical notation
+=item 'trunc'
-Big integer values are strings of the form C</^[+-]\d+$/> with leading
-zeros suppressed.
+truncation invariably removes all digits following the
+rounding place, replacing them with zeros. Thus, 987.65 rounded
+to tens (P=1) becomes 980, and rounded to the fourth sigdig
+becomes 987.6 (A=4). 123.456 rounded to the second place after the
+decimal point (P=-2) becomes 123.46.
- '-0' canonical value '-0', normalized '0'
- ' -123_123_123' canonical value '-123123123'
- '1_23_456_7890' canonical value '1234567890'
+All other implemented styles of rounding attempt to round to the
+"nearest digit." If the digit D immediately to the right of the
+rounding place (skipping the decimal point) is greater than 5, the
+number is incremented at the rounding place (possibly causing a
+cascade of incrementation): e.g. when rounding to units, 0.9 rounds
+to 1, and -19.9 rounds to -20. If D < 5, the number is similarly
+truncated at the rounding place: e.g. when rounding to units, 0.4
+rounds to 0, and -19.4 rounds to -19.
-=item Input
+However the results of other styles of rounding differ if the
+digit immediately to the right of the rounding place (skipping the
+decimal point) is 5 and if there are no digits, or no digits other
+than 0, after that 5. In such cases:
-Input values to these routines may be either Math::BigInt objects or
-strings of the form C</^\s*[+-]?[\d]+\.?[\d]*E?[+-]?[\d]*$/>.
+=item 'even'
-You can include one underscore between any two digits.
+rounds the digit at the rounding place to 0, 2, 4, 6, or 8
+if it is not already. E.g., when rounding to the first sigdig, 0.45
+becomes 0.4, -0.55 becomes -0.6, but 0.4501 becomes 0.5.
-This means integer values like 1.01E2 or even 1000E-2 are also accepted.
-Non integer values result in NaN.
+=item 'odd'
-Math::BigInt::new() defaults to 0, while Math::BigInt::new('') results
-in 'NaN'.
+rounds the digit at the rounding place to 1, 3, 5, 7, or 9 if
+it is not already. E.g., when rounding to the first sigdig, 0.45
+becomes 0.5, -0.55 becomes -0.5, but 0.5501 becomes 0.6.
-bnorm() on a BigInt object is now effectively a no-op, since the numbers
-are always stored in normalized form. On a string, it creates a BigInt
-object.
+=item '+inf'
-=item Output
+round to plus infinity, i.e. always round up. E.g., when
+rounding to the first sigdig, 0.45 becomes 0.5, -0.55 becomes -0.5,
+and 0.4501 also becomes 0.5.
-Output values are BigInt objects (normalized), except for bstr(), which
-returns a string in normalized form.
-Some routines (C<is_odd()>, C<is_even()>, C<is_zero()>, C<is_one()>,
-C<is_nan()>) return true or false, while others (C<bcmp()>, C<bacmp()>)
-return either undef, <0, 0 or >0 and are suited for sort.
+=item '-inf'
+
+round to minus infinity, i.e. always round down. E.g., when
+rounding to the first sigdig, 0.45 becomes 0.4, -0.55 becomes -0.6,
+but 0.4501 becomes 0.5.
+
+=item 'zero'
+
+round to zero, i.e. positive numbers down, negative ones up.
+E.g., when rounding to the first sigdig, 0.45 becomes 0.4, -0.55
+becomes -0.5, but 0.4501 becomes 0.5.
+
+=back
+
+The handling of A & P in MBI/MBF (the old core code shipped with Perl
+versions <= 5.7.2) is like this:
+
+=over 2
+
+=item Precision
+
+ * ffround($p) is able to round to $p number of digits after the decimal
+ point
+ * otherwise P is unused
+
+=item Accuracy (significant digits)
+
+ * fround($a) rounds to $a significant digits
+ * only fdiv() and fsqrt() take A as (optional) paramater
+ + other operations simply create the same number (fneg etc), or more (fmul)
+ of digits
+ + rounding/truncating is only done when explicitly calling one of fround
+ or ffround, and never for BigInt (not implemented)
+ * fsqrt() simply hands its accuracy argument over to fdiv.
+ * the documentation and the comment in the code indicate two different ways
+ on how fdiv() determines the maximum number of digits it should calculate,
+ and the actual code does yet another thing
+ POD:
+ max($Math::BigFloat::div_scale,length(dividend)+length(divisor))
+ Comment:
+ result has at most max(scale, length(dividend), length(divisor)) digits
+ Actual code:
+ scale = max(scale, length(dividend)-1,length(divisor)-1);
+ scale += length(divisor) - length(dividend);
+ So for lx = 3, ly = 9, scale = 10, scale will actually be 16 (10+9-3).
+ Actually, the 'difference' added to the scale is calculated from the
+ number of "significant digits" in dividend and divisor, which is derived
+ by looking at the length of the mantissa. Which is wrong, since it includes
+ the + sign (oops) and actually gets 2 for '+100' and 4 for '+101'. Oops
+ again. Thus 124/3 with div_scale=1 will get you '41.3' based on the strange
+ assumption that 124 has 3 significant digits, while 120/7 will get you
+ '17', not '17.1' since 120 is thought to have 2 significant digits.
+ The rounding after the division then uses the remainder and $y to determine
+ wether it must round up or down.
+ ? I have no idea which is the right way. That's why I used a slightly more
+ ? simple scheme and tweaked the few failing testcases to match it.
+
+=back
+
+This is how it works now:
+
+=over 2
+
+=item Setting/Accessing
+
+ * You can set the A global via C<< Math::BigInt->accuracy() >> or
+ C<< Math::BigFloat->accuracy() >> or whatever class you are using.
+ * You can also set P globally by using C<< Math::SomeClass->precision() >>
+ likewise.
+ * Globals are classwide, and not inherited by subclasses.
+ * to undefine A, use C<< Math::SomeCLass->accuracy(undef); >>
+ * to undefine P, use C<< Math::SomeClass->precision(undef); >>
+ * Setting C<< Math::SomeClass->accuracy() >> clears automatically
+ C<< Math::SomeClass->precision() >>, and vice versa.
+ * To be valid, A must be > 0, P can have any value.
+ * If P is negative, this means round to the P'th place to the right of the
+ decimal point; positive values mean to the left of the decimal point.
+ P of 0 means round to integer.
+ * to find out the current global A, use C<< Math::SomeClass->accuracy() >>
+ * to find out the current global P, use C<< Math::SomeClass->precision() >>
+ * use C<< $x->accuracy() >> respective C<< $x->precision() >> for the local
+ setting of C<< $x >>.
+ * Please note that C<< $x->accuracy() >> respective C<< $x->precision() >>
+ return eventually defined global A or P, when C<< $x >>'s A or P is not
+ set.
+
+=item Creating numbers
+
+ * When you create a number, you can give it's desired A or P via:
+ $x = Math::BigInt->new($number,$A,$P);
+ * Only one of A or P can be defined, otherwise the result is NaN
+ * If no A or P is give ($x = Math::BigInt->new($number) form), then the
+ globals (if set) will be used. Thus changing the global defaults later on
+ will not change the A or P of previously created numbers (i.e., A and P of
+ $x will be what was in effect when $x was created)
+ * If given undef for A and P, B<no> rounding will occur, and the globals will
+ B<not> be used. This is used by subclasses to create numbers without
+ suffering rounding in the parent. Thus a subclass is able to have it's own
+ globals enforced upon creation of a number by using
+ C<< $x = Math::BigInt->new($number,undef,undef) >>:
+
+ use Math::BigInt::SomeSubclass;
+ use Math::BigInt;
+
+ Math::BigInt->accuracy(2);
+ Math::BigInt::SomeSubClass->accuracy(3);
+ $x = Math::BigInt::SomeSubClass->new(1234);
+
+ $x is now 1230, and not 1200. A subclass might choose to implement
+ this otherwise, e.g. falling back to the parent's A and P.
+
+=item Usage
+
+ * If A or P are enabled/defined, they are used to round the result of each
+ operation according to the rules below
+ * Negative P is ignored in Math::BigInt, since BigInts never have digits
+ after the decimal point
+ * Math::BigFloat uses Math::BigInt internally, but setting A or P inside
+ Math::BigInt as globals does not tamper with the parts of a BigFloat.
+ A flag is used to mark all Math::BigFloat numbers as 'never round'.
+
+=item Precedence
+
+ * It only makes sense that a number has only one of A or P at a time.
+ If you set either A or P on one object, or globally, the other one will
+ be automatically cleared.
+ * If two objects are involved in an operation, and one of them has A in
+ effect, and the other P, this results in an error (NaN).
+ * A takes precedence over P (Hint: A comes before P).
+ If neither of them is defined, nothing is used, i.e. the result will have
+ as many digits as it can (with an exception for fdiv/fsqrt) and will not
+ be rounded.
+ * There is another setting for fdiv() (and thus for fsqrt()). If neither of
+ A or P is defined, fdiv() will use a fallback (F) of $div_scale digits.
+ If either the dividend's or the divisor's mantissa has more digits than
+ the value of F, the higher value will be used instead of F.
+ This is to limit the digits (A) of the result (just consider what would
+ happen with unlimited A and P in the case of 1/3 :-)
+ * fdiv will calculate (at least) 4 more digits than required (determined by
+ A, P or F), and, if F is not used, round the result
+ (this will still fail in the case of a result like 0.12345000000001 with A
+ or P of 5, but this can not be helped - or can it?)
+ * Thus you can have the math done by on Math::Big* class in two modi:
+ + never round (this is the default):
+ This is done by setting A and P to undef. No math operation
+ will round the result, with fdiv() and fsqrt() as exceptions to guard
+ against overflows. You must explicitly call bround(), bfround() or
+ round() (the latter with parameters).
+ Note: Once you have rounded a number, the settings will 'stick' on it
+ and 'infect' all other numbers engaged in math operations with it, since
+ local settings have the highest precedence. So, to get SaferRound[tm],
+ use a copy() before rounding like this:
+
+ $x = Math::BigFloat->new(12.34);
+ $y = Math::BigFloat->new(98.76);
+ $z = $x * $y; # 1218.6984
+ print $x->copy()->fround(3); # 12.3 (but A is now 3!)
+ $z = $x * $y; # still 1218.6984, without
+ # copy would have been 1210!
+
+ + round after each op:
+ After each single operation (except for testing like is_zero()), the
+ method round() is called and the result is rounded appropriately. By
+ setting proper values for A and P, you can have all-the-same-A or
+ all-the-same-P modes. For example, Math::Currency might set A to undef,
+ and P to -2, globally.
+
+ ?Maybe an extra option that forbids local A & P settings would be in order,
+ ?so that intermediate rounding does not 'poison' further math?
+
+=item Overriding globals
+
+ * you will be able to give A, P and R as an argument to all the calculation
+ routines; the second parameter is A, the third one is P, and the fourth is
+ R (shift right by one for binary operations like badd). P is used only if
+ the first parameter (A) is undefined. These three parameters override the
+ globals in the order detailed as follows, i.e. the first defined value
+ wins:
+ (local: per object, global: global default, parameter: argument to sub)
+ + parameter A
+ + parameter P
+ + local A (if defined on both of the operands: smaller one is taken)
+ + local P (if defined on both of the operands: bigger one is taken)
+ + global A
+ + global P
+ + global F
+ * fsqrt() will hand its arguments to fdiv(), as it used to, only now for two
+ arguments (A and P) instead of one
+
+=item Local settings
+
+ * You can set A or P locally by using C<< $x->accuracy() >> or
+ C<< $x->precision() >>
+ and thus force different A and P for different objects/numbers.
+ * Setting A or P this way immediately rounds $x to the new value.
+ * C<< $x->accuracy() >> clears C<< $x->precision() >>, and vice versa.
+
+=item Rounding
+
+ * the rounding routines will use the respective global or local settings.
+ fround()/bround() is for accuracy rounding, while ffround()/bfround()
+ is for precision
+ * the two rounding functions take as the second parameter one of the
+ following rounding modes (R):
+ 'even', 'odd', '+inf', '-inf', 'zero', 'trunc'
+ * you can set/get the global R by using C<< Math::SomeClass->round_mode() >>
+ or by setting C<< $Math::SomeClass::round_mode >>
+ * after each operation, C<< $result->round() >> is called, and the result may
+ eventually be rounded (that is, if A or P were set either locally,
+ globally or as parameter to the operation)
+ * to manually round a number, call C<< $x->round($A,$P,$round_mode); >>
+ this will round the number by using the appropriate rounding function
+ and then normalize it.
+ * rounding modifies the local settings of the number:
+
+ $x = Math::BigFloat->new(123.456);
+ $x->accuracy(5);
+ $x->bround(4);
+
+ Here 4 takes precedence over 5, so 123.5 is the result and $x->accuracy()
+ will be 4 from now on.
+
+=item Default values
+
+ * R: 'even'
+ * F: 40
+ * A: undef
+ * P: undef
+
+=item Remarks
+
+ * The defaults are set up so that the new code gives the same results as
+ the old code (except in a few cases on fdiv):
+ + Both A and P are undefined and thus will not be used for rounding
+ after each operation.
+ + round() is thus a no-op, unless given extra parameters A and P
=back
-=head2 Rounding
+=head1 Infinity and Not a Number
-Only C<bround()> is defined for BigInts, for further details of rounding see
-L<Math::BigFloat>.
+While BigInt has extensive handling of inf and NaN, certain quirks remain.
=over 2
-=item bfround ( +$scale ) rounds to the $scale'th place left from the '.'
+=item oct()/hex()
+
+These perl routines currently (as of Perl v.5.8.6) cannot handle passed
+inf.
+
+ te@linux:~> perl -wle 'print 2 ** 3333'
+ inf
+ te@linux:~> perl -wle 'print 2 ** 3333 == 2 ** 3333'
+ 1
+ te@linux:~> perl -wle 'print oct(2 ** 3333)'
+ 0
+ te@linux:~> perl -wle 'print hex(2 ** 3333)'
+ Illegal hexadecimal digit 'i' ignored at -e line 1.
+ 0
+
+The same problems occur if you pass them Math::BigInt->binf() objects. Since
+overloading these routines is not possible, this cannot be fixed from BigInt.
+
+=item ==, !=, <, >, <=, >= with NaNs
+
+BigInt's bcmp() routine currently returns undef to signal that a NaN was
+involved in a comparison. However, the overload code turns that into
+either 1 or '' and thus operations like C<< NaN != NaN >> might return
+wrong values.
+
+=item log(-inf)
-=item bround ( +$scale ) preserves accuracy to $scale sighnificant digits counted from the left and paddes the number with zeros
+C<< log(-inf) >> is highly weird. Since log(-x)=pi*i+log(x), then
+log(-inf)=pi*i+inf. However, since the imaginary part is finite, the real
+infinity "overshadows" it, so the number might as well just be infinity.
+However, the result is a complex number, and since BigInt/BigFloat can only
+have real numbers as results, the result is NaN.
-=item bround ( -$scale ) preserves accuracy to $scale significant digits counted from the right and paddes the number with zeros.
+=item exp(), cos(), sin(), atan2()
+These all might have problems handling infinity right.
+
=back
-C<bfround()> does nothing in case of negative C<$scale>. Both C<bround()> and
-C<bfround()> are a no-ops for a scale of 0.
+=head1 INTERNALS
+
+The actual numbers are stored as unsigned big integers (with seperate sign).
+
+You should neither care about nor depend on the internal representation; it
+might change without notice. Use B<ONLY> method calls like C<< $x->sign(); >>
+instead relying on the internal representation.
+
+=head2 MATH LIBRARY
+
+Math with the numbers is done (by default) by a module called
+C<Math::BigInt::Calc>. This is equivalent to saying:
+
+ use Math::BigInt lib => 'Calc';
+
+You can change this by using:
+
+ use Math::BigInt lib => 'BitVect';
-All rounding functions take as a second parameter a rounding mode from one of
-the following: 'even', 'odd', '+inf', '-inf', 'zero' or 'trunc'.
+The following would first try to find Math::BigInt::Foo, then
+Math::BigInt::Bar, and when this also fails, revert to Math::BigInt::Calc:
-The default is 'even'. By using C<< Math::BigInt->round_mode($rnd_mode); >>
-you can get and set the default round mode for subsequent rounding.
+ use Math::BigInt lib => 'Foo,Math::BigInt::Bar';
-The second parameter to the round functions than overrides the default
-temporarily.
+Since Math::BigInt::GMP is in almost all cases faster than Calc (especially in
+math involving really big numbers, where it is B<much> faster), and there is
+no penalty if Math::BigInt::GMP is not installed, it is a good idea to always
+use the following:
-=head2 Internals
+ use Math::BigInt lib => 'GMP';
-Actual math is done in an internal format consisting of an array of
-elements of base 100000 digits with the least significant digit first.
-The sign C</^[+-]$/> is stored separately. The string 'NaN' is used to
-represent the result when input arguments are not numbers, as well as
-the result of dividing by zero.
+Different low-level libraries use different formats to store the
+numbers. You should B<NOT> depend on the number having a specific format
+internally.
-You sould neither care nor depend on the internal represantation, it might
-change without notice. Use only method calls like C<< $x->sign(); >> instead
-relying on the internal hash keys like in C<< $x->{sign}; >>.
+See the respective math library module documentation for further details.
+
+=head2 SIGN
+
+The sign is either '+', '-', 'NaN', '+inf' or '-inf'.
+
+A sign of 'NaN' is used to represent the result when input arguments are not
+numbers or as a result of 0/0. '+inf' and '-inf' represent plus respectively
+minus infinity. You will get '+inf' when dividing a positive number by 0, and
+'-inf' when dividing any negative number by 0.
=head2 mantissa(), exponent() and parts()
$y = $m * ( 10 ** $e );
print "ok\n" if $x == $y;
-C<($m,$e) = $x->parts()> is just a shortcut that gives you both of them in one
-go. Both the returned mantissa and exponent do have a sign.
+C<< ($m,$e) = $x->parts() >> is just a shortcut that gives you both of them
+in one go. Both the returned mantissa and exponent have a sign.
-Currently, for BigInts C<$e> will be always 0, except for NaN where it will be
-NaN and for $x == 0, then it will be 1 (to be compatible with Math::BigFlaot's
-internal representation of a zero as C<0E1>).
+Currently, for BigInts C<$e> is always 0, except for NaN, +inf and -inf,
+where it is C<NaN>; and for C<$x == 0>, where it is C<1> (to be compatible
+with Math::BigFloat's internal representation of a zero as C<0E1>).
+
+C<$m> is currently just a copy of the original number. The relation between
+C<$e> and C<$m> will stay always the same, though their real values might
+change.
-C<$m> will always be a copy of the original number. The relation between $e
-and $m might change in the future, but will be always equivalent in a
-numerical sense, e.g. $m might get minized.
-
=head1 EXAMPLES
- use Math::BigInt qw(bstr bint);
- $x = bstr("1234") # string "1234"
+ use Math::BigInt;
+
+ sub bint { Math::BigInt->new(shift); }
+
+ $x = Math::BigInt->bstr("1234") # string "1234"
$x = "$x"; # same as bstr()
- $x = bneg("1234") # Bigint "-1234"
- $x = Math::BigInt->bneg("1234"); # Bigint "-1234"
- $x = Math::BigInt->babs("-12345"); # Bigint "12345"
+ $x = Math::BigInt->bneg("1234"); # BigInt "-1234"
+ $x = Math::BigInt->babs("-12345"); # BigInt "12345"
$x = Math::BigInt->bnorm("-0 00"); # BigInt "0"
$x = bint(1) + bint(2); # BigInt "3"
$x = bint(1) + "2"; # ditto (auto-BigIntify of "2")
$x = $x + 5 / 2; # BigInt "3"
$x = $x ** 3; # BigInt "27"
$x *= 2; # BigInt "54"
- $x = new Math::BigInt; # BigInt "0"
+ $x = Math::BigInt->new(0); # BigInt "0"
$x--; # BigInt "-1"
$x = Math::BigInt->badd(4,5) # BigInt "9"
- $x = Math::BigInt::badd(4,5) # BigInt "9"
print $x->bsstr(); # 9e+0
+Examples for rounding:
+
+ use Math::BigFloat;
+ use Test;
+
+ $x = Math::BigFloat->new(123.4567);
+ $y = Math::BigFloat->new(123.456789);
+ Math::BigFloat->accuracy(4); # no more A than 4
+
+ ok ($x->copy()->fround(),123.4); # even rounding
+ print $x->copy()->fround(),"\n"; # 123.4
+ Math::BigFloat->round_mode('odd'); # round to odd
+ print $x->copy()->fround(),"\n"; # 123.5
+ Math::BigFloat->accuracy(5); # no more A than 5
+ Math::BigFloat->round_mode('odd'); # round to odd
+ print $x->copy()->fround(),"\n"; # 123.46
+ $y = $x->copy()->fround(4),"\n"; # A = 4: 123.4
+ print "$y, ",$y->accuracy(),"\n"; # 123.4, 4
+
+ Math::BigFloat->accuracy(undef); # A not important now
+ Math::BigFloat->precision(2); # P important
+ print $x->copy()->bnorm(),"\n"; # 123.46
+ print $x->copy()->fround(),"\n"; # 123.46
+
+Examples for converting:
+
+ my $x = Math::BigInt->new('0b1'.'01' x 123);
+ print "bin: ",$x->as_bin()," hex:",$x->as_hex()," dec: ",$x,"\n";
+
=head1 Autocreating constants
-After C<use Math::BigInt ':constant'> all the B<integer> decimal constants
-in the given scope are converted to C<Math::BigInt>. This conversion
-happens at compile time.
+After C<use Math::BigInt ':constant'> all the B<integer> decimal, hexadecimal
+and binary constants in the given scope are converted to C<Math::BigInt>.
+This conversion happens at compile time.
-In particular
+In particular,
perl -MMath::BigInt=:constant -e 'print 2**100,"\n"'
-prints the integer value of C<2**100>. Note that without conversion of
-constants the expression 2**100 will be calculated as floating point
-number.
+prints the integer value of C<2**100>. Note that without conversion of
+constants the expression 2**100 will be calculated as perl scalar.
Please note that strings and floating point constants are not affected,
so that
$x = 1234567890123456789012345678901234567890
+ 123456789123456789;
- $x = '1234567890123456789012345678901234567890'
+ $y = '1234567890123456789012345678901234567890'
+ '123456789123456789';
-do both not work. You need a explicit Math::BigInt->new() around one of them.
+do not work. You need an explicit Math::BigInt->new() around one of the
+operands. You should also quote large constants to protect loss of precision:
+
+ use Math::BigInt;
+
+ $x = Math::BigInt->new('1234567889123456789123456789123456789');
+
+Without the quotes Perl would convert the large number to a floating point
+constant at compile time and then hand the result to BigInt, which results in
+an truncated result or a NaN.
+
+This also applies to integers that look like floating point constants:
+
+ use Math::BigInt ':constant';
+
+ print ref(123e2),"\n";
+ print ref(123.2e2),"\n";
+
+will print nothing but newlines. Use either L<bignum> or L<Math::BigFloat>
+to get this to work.
=head1 PERFORMANCE
Using the form $x += $y; etc over $x = $x + $y is faster, since a copy of $x
must be made in the second case. For long numbers, the copy can eat up to 20%
-of the work (in case of addition/subtraction, less for
+of the work (in the case of addition/subtraction, less for
multiplication/division). If $y is very small compared to $x, the form
$x += $y is MUCH faster than $x = $x + $y since making the copy of $x takes
more time then the actual addition.
-With a technic called copy-on-write the cost of copying with overload could
-be minimized or even completely avoided. This is currently not implemented.
+With a technique called copy-on-write, the cost of copying with overload could
+be minimized or even completely avoided. A test implementation of COW did show
+performance gains for overloaded math, but introduced a performance loss due
+to a constant overhead for all other operations. So Math::BigInt does currently
+not COW.
+
+The rewritten version of this module (vs. v0.01) is slower on certain
+operations, like C<new()>, C<bstr()> and C<numify()>. The reason are that it
+does now more work and handles much more cases. The time spent in these
+operations is usually gained in the other math operations so that code on
+the average should get (much) faster. If they don't, please contact the author.
+
+Some operations may be slower for small numbers, but are significantly faster
+for big numbers. Other operations are now constant (O(1), like C<bneg()>,
+C<babs()> etc), instead of O(N) and thus nearly always take much less time.
+These optimizations were done on purpose.
+
+If you find the Calc module to slow, try to install any of the replacement
+modules and see if they help you.
+
+=head2 Alternative math libraries
+
+You can use an alternative library to drive Math::BigInt via:
+
+ use Math::BigInt lib => 'Module';
+
+See L<MATH LIBRARY> for more information.
+
+For more benchmark results see L<http://bloodgate.com/perl/benchmarks.html>.
+
+=head2 SUBCLASSING
+
+=head1 Subclassing Math::BigInt
+
+The basic design of Math::BigInt allows simple subclasses with very little
+work, as long as a few simple rules are followed:
+
+=over 2
+
+=item *
+
+The public API must remain consistent, i.e. if a sub-class is overloading
+addition, the sub-class must use the same name, in this case badd(). The
+reason for this is that Math::BigInt is optimized to call the object methods
+directly.
+
+=item *
+
+The private object hash keys like C<$x->{sign}> may not be changed, but
+additional keys can be added, like C<$x->{_custom}>.
-The new version of this module is slower on new(), bstr() and numify(). Some
-operations may be slower for small numbers, but are significantly faster for
-big numbers. Other operations are now constant (O(1), like bneg(), babs()
-etc), instead of O(N) and thus nearly always take much less time.
+=item *
-For more benchmark results see http://bloodgate.com/perl/benchmarks.html
+Accessor functions are available for all existing object hash keys and should
+be used instead of directly accessing the internal hash keys. The reason for
+this is that Math::BigInt itself has a pluggable interface which permits it
+to support different storage methods.
+
+=back
+
+More complex sub-classes may have to replicate more of the logic internal of
+Math::BigInt if they need to change more basic behaviors. A subclass that
+needs to merely change the output only needs to overload C<bstr()>.
+
+All other object methods and overloaded functions can be directly inherited
+from the parent class.
+
+At the very minimum, any subclass will need to provide it's own C<new()> and can
+store additional hash keys in the object. There are also some package globals
+that must be defined, e.g.:
+
+ # Globals
+ $accuracy = undef;
+ $precision = -2; # round to 2 decimal places
+ $round_mode = 'even';
+ $div_scale = 40;
+
+Additionally, you might want to provide the following two globals to allow
+auto-upgrading and auto-downgrading to work correctly:
+
+ $upgrade = undef;
+ $downgrade = undef;
+
+This allows Math::BigInt to correctly retrieve package globals from the
+subclass, like C<$SubClass::precision>. See t/Math/BigInt/Subclass.pm or
+t/Math/BigFloat/SubClass.pm completely functional subclass examples.
+
+Don't forget to
+
+ use overload;
+
+in your subclass to automatically inherit the overloading from the parent. If
+you like, you can change part of the overloading, look at Math::String for an
+example.
+
+=head1 UPGRADING
+
+When used like this:
+
+ use Math::BigInt upgrade => 'Foo::Bar';
+
+certain operations will 'upgrade' their calculation and thus the result to
+the class Foo::Bar. Usually this is used in conjunction with Math::BigFloat:
+
+ use Math::BigInt upgrade => 'Math::BigFloat';
+
+As a shortcut, you can use the module C<bignum>:
+
+ use bignum;
+
+Also good for oneliners:
+
+ perl -Mbignum -le 'print 2 ** 255'
+
+This makes it possible to mix arguments of different classes (as in 2.5 + 2)
+as well es preserve accuracy (as in sqrt(3)).
+
+Beware: This feature is not fully implemented yet.
+
+=head2 Auto-upgrade
+
+The following methods upgrade themselves unconditionally; that is if upgrade
+is in effect, they will always hand up their work:
+
+=over 2
+
+=item bsqrt()
+
+=item div()
+
+=item blog()
+
+=back
+
+Beware: This list is not complete.
+
+All other methods upgrade themselves only when one (or all) of their
+arguments are of the class mentioned in $upgrade (This might change in later
+versions to a more sophisticated scheme):
=head1 BUGS
=over 2
-=item :constant and eval()
+=item broot() does not work
+
+The broot() function in BigInt may only work for small values. This will be
+fixed in a later version.
+
+=item Out of Memory!
Under Perl prior to 5.6.0 having an C<use Math::BigInt ':constant';> and
C<eval()> in your code will crash with "Out of memory". This is probably an
overload/exporter bug. You can workaround by not having C<eval()>
-and ':constant' at the same time or upgrade your Perl.
+and ':constant' at the same time or upgrade your Perl to a newer version.
+
+=item Fails to load Calc on Perl prior 5.6.0
+
+Since eval(' use ...') can not be used in conjunction with ':constant', BigInt
+will fall back to eval { require ... } when loading the math lib on Perls
+prior to 5.6.0. This simple replaces '::' with '/' and thus might fail on
+filesystems using a different seperator.
=back
=over 1
-=item stringify, bstr(), bsstr() and 'cmp'
+=item bstr(), bsstr() and 'cmp'
-Both stringify and bstr() now drop the leading '+'. The old code would return
-'+3', the new returns '3'. This is to be consistent with Perl and to make
-cmp (especially with overloading) to work as you expect. It also solves
-problems with Test.pm, it's ok() uses 'eq' internally.
+Both C<bstr()> and C<bsstr()> as well as automated stringify via overload now
+drop the leading '+'. The old code would return '+3', the new returns '3'.
+This is to be consistent with Perl and to make C<cmp> (especially with
+overloading) to work as you expect. It also solves problems with C<Test.pm>,
+because it's C<ok()> uses 'eq' internally.
-Mark said, when asked about to drop the '+' altogether, or make only cmp work:
+Mark Biggar said, when asked about to drop the '+' altogether, or make only
+C<cmp> work:
I agree (with the first alternative), don't add the '+' on positive
numbers. It's not as important anymore with the new internal
There is now a C<bsstr()> method to get the string in scientific notation aka
C<1e+2> instead of C<100>. Be advised that overloaded 'eq' always uses bstr()
-for comparisation, but Perl will represent some numbers as 100 and others
-as 1e+308. If in doubt, convert both arguments to Math::BigInt before doing eq:
+for comparison, but Perl will represent some numbers as 100 and others
+as 1e+308. If in doubt, convert both arguments to Math::BigInt before
+comparing them as strings:
use Test;
BEGIN { plan tests => 3 }
$y = Math::BigInt->new($y);
ok ($x,$y); # okay
+Alternatively, simple use C<< <=> >> for comparisons, this will get it
+always right. There is not yet a way to get a number automatically represented
+as a string that matches exactly the way Perl represents it.
+
+See also the section about L<Infinity and Not a Number> for problems in
+comparing NaNs.
+
=item int()
C<int()> will return (at least for Perl v5.7.1 and up) another BigInt, not a
$x = Math::BigFloat->new(123.45);
$y = int($x); # BigInt 123
-In all Perl versions you can use C<as_number()> for the same effect:
+In all Perl versions you can use C<as_number()> or C<as_int> for the same
+effect:
$x = Math::BigFloat->new(123.45);
$y = $x->as_number(); # BigInt 123
+ $y = $x->as_int(); # ditto
This also works for other subclasses, like Math::String.
+It is yet unclear whether overloaded int() should return a scalar or a BigInt.
+
+If you want a real Perl scalar, use C<numify()>:
+
+ $y = $x->numify(); # 123 as scalar
+
+This is seldom necessary, though, because this is done automatically, like
+when you access an array:
+
+ $z = $array[$x]; # does work automatically
+
+=item length
+
+The following will probably not do what you expect:
+
+ $c = Math::BigInt->new(123);
+ print $c->length(),"\n"; # prints 30
+
+It prints both the number of digits in the number and in the fraction part
+since print calls C<length()> in list context. Use something like:
+
+ print scalar $c->length(),"\n"; # prints 3
+
=item bdiv
The following will probably not do what you expect:
print $c->bdiv(10000),"\n";
-It prints both quotient and reminder since print calls C<bdiv()> in list
-context. Also, C<bdiv()> will modify $c, so be carefull. You probably want
+It prints both quotient and remainder since print calls C<bdiv()> in list
+context. Also, C<bdiv()> will modify $c, so be careful. You probably want
to use
print $c / 10000,"\n";
nonzero) always has the same sign as the second operand; so, for
example,
- 1 / 4 => ( 0, 1)
- 1 / -4 => (-1,-3)
- -3 / 4 => (-1, 1)
- -3 / -4 => ( 0,-3)
+ 1 / 4 => ( 0, 1)
+ 1 / -4 => (-1,-3)
+ -3 / 4 => (-1, 1)
+ -3 / -4 => ( 0,-3)
+ -11 / 2 => (-5,1)
+ 11 /-2 => (-5,-1)
As a consequence, the behavior of the operator % agrees with the
behavior of Perl's built-in % operator (as documented in the perlop
$x == ($x / $y) * $y + ($x % $y)
holds true for any $x and $y, which justifies calling the two return
-values of bdiv() the quotient and remainder.
+values of bdiv() the quotient and remainder. The only exception to this rule
+are when $y == 0 and $x is negative, then the remainder will also be
+negative. See below under "infinity handling" for the reasoning behind this.
Perl's 'use integer;' changes the behaviour of % and / for scalars, but will
not change BigInt's way to do things. This is because under 'use integer' Perl
system. If you need BigInt's behaving exactly like Perl's 'use integer', bug
the author to implement it ;)
+=item infinity handling
+
+Here are some examples that explain the reasons why certain results occur while
+handling infinity:
+
+The following table shows the result of the division and the remainder, so that
+the equation above holds true. Some "ordinary" cases are strewn in to show more
+clearly the reasoning:
+
+ A / B = C, R so that C * B + R = A
+ =========================================================
+ 5 / 8 = 0, 5 0 * 8 + 5 = 5
+ 0 / 8 = 0, 0 0 * 8 + 0 = 0
+ 0 / inf = 0, 0 0 * inf + 0 = 0
+ 0 /-inf = 0, 0 0 * -inf + 0 = 0
+ 5 / inf = 0, 5 0 * inf + 5 = 5
+ 5 /-inf = 0, 5 0 * -inf + 5 = 5
+ -5/ inf = 0, -5 0 * inf + -5 = -5
+ -5/-inf = 0, -5 0 * -inf + -5 = -5
+ inf/ 5 = inf, 0 inf * 5 + 0 = inf
+ -inf/ 5 = -inf, 0 -inf * 5 + 0 = -inf
+ inf/ -5 = -inf, 0 -inf * -5 + 0 = inf
+ -inf/ -5 = inf, 0 inf * -5 + 0 = -inf
+ 5/ 5 = 1, 0 1 * 5 + 0 = 5
+ -5/ -5 = 1, 0 1 * -5 + 0 = -5
+ inf/ inf = 1, 0 1 * inf + 0 = inf
+ -inf/-inf = 1, 0 1 * -inf + 0 = -inf
+ inf/-inf = -1, 0 -1 * -inf + 0 = inf
+ -inf/ inf = -1, 0 1 * -inf + 0 = -inf
+ 8/ 0 = inf, 8 inf * 0 + 8 = 8
+ inf/ 0 = inf, inf inf * 0 + inf = inf
+ 0/ 0 = NaN
+
+These cases below violate the "remainder has the sign of the second of the two
+arguments", since they wouldn't match up otherwise.
+
+ A / B = C, R so that C * B + R = A
+ ========================================================
+ -inf/ 0 = -inf, -inf -inf * 0 + inf = -inf
+ -8/ 0 = -inf, -8 -inf * 0 + 8 = -8
+
=item Modifying and =
Beware of:
It will not do what you think, e.g. making a copy of $x. Instead it just makes
a second reference to the B<same> object and stores it in $y. Thus anything
-that modifies $x will modify $y, and vice versa.
+that modifies $x (except overloaded operators) will modify $y, and vice versa.
+Or in other words, C<=> is only safe if you modify your BigInts only via
+overloaded math. As soon as you use a method call it breaks:
$x->bmul(2);
print "$x, $y\n"; # prints '10, 10'
$y = $x->copy();
-See also the documentation in L<overload> regarding C<=>.
+You can also chain the calls like this, this will make first a copy and then
+multiply it by 2:
+
+ $y = $x->copy()->bmul(2);
+
+See also the documentation for overload.pm regarding C<=>.
=item bpow
C<bpow()> (and the rounding functions) now modifies the first argument and
-return it, unlike the old code which left it alone and only returned the
+returns it, unlike the old code which left it alone and only returned the
result. This is to be consistent with C<badd()> etc. The first three will
modify $x, the last one won't:
since overload calls C<sub($x,0,1);> instead of C<neg($x)>. The first variant
needs to preserve $x since it does not know that it later will get overwritten.
-This makes a copy of $x and takes O(N). But $x->bneg() is O(1).
-
-With Copy-On-Write, this issue will be gone. Stay tuned...
+This makes a copy of $x and takes O(N), but $x->bneg() is O(1).
=item Mixing different object types
$integer = $mbi2 / $mbf; # $mbi2->bdiv()
This is because math with overloaded operators follows the first (dominating)
-operand, this one's operation is called and returns thus the result. So,
+operand, and the operation of that is called and returns thus the result. So,
Math::BigInt::bdiv() will always return a Math::BigInt, regardless whether
the result should be a Math::BigFloat or the second operant is one.
$float = Math::BigFloat->new($mbi2 / $mbi); # = 2.0 thus wrong!
-Beware of the order of more complicated expressions like:
+Beware also of the order of more complicated expressions like:
$integer = ($mbi2 + $mbi) / $mbf; # int / float => int
$integer = $mbi2 / Math::BigFloat->new($mbi); # ditto
This section also applies to other overloaded math packages, like Math::String.
+One solution to you problem might be autoupgrading|upgrading. See the
+pragmas L<bignum>, L<bigint> and L<bigrat> for an easy way to do this.
+
=item bsqrt()
-C<bsqrt()> works only good if the result is an big integer, e.g. the square
+C<bsqrt()> works only good if the result is a big integer, e.g. the square
root of 144 is 12, but from 12 the square root is 3, regardless of rounding
-mode.
+mode. The reason is that the result is always truncated to an integer.
If you want a better approximation of the square root, then use:
$x = Math::BigFloat->new(12);
- $Math::BigFloat::precision = 0;
+ Math::BigFloat->precision(0);
Math::BigFloat->round_mode('even');
print $x->copy->bsqrt(),"\n"; # 4
- $Math::BigFloat::precision = 2;
+ Math::BigFloat->precision(2);
print $x->bsqrt(),"\n"; # 3.46
print $x->bsqrt(3),"\n"; # 3.464
+=item brsft()
+
+For negative numbers in base see also L<brsft|brsft>.
+
=back
=head1 LICENSE
This program is free software; you may redistribute it and/or modify it under
the same terms as Perl itself.
+=head1 SEE ALSO
+
+L<Math::BigFloat>, L<Math::BigRat> and L<Math::Big> as well as
+L<Math::BigInt::BitVect>, L<Math::BigInt::Pari> and L<Math::BigInt::GMP>.
+
+The pragmas L<bignum>, L<bigint> and L<bigrat> also might be of interest
+because they solve the autoupgrading/downgrading issue, at least partly.
+
+The package at
+L<http://search.cpan.org/search?mode=module&query=Math%3A%3ABigInt> contains
+more documentation including a full version history, testcases, empty
+subclass files and benchmarks.
+
=head1 AUTHORS
Original code by Mark Biggar, overloaded interface by Ilya Zakharevich.
-Completely rewritten by Tels http://bloodgate.com in late 2000, 2001.
+Completely rewritten by Tels http://bloodgate.com in late 2000, 2001 - 2004
+and still at it in 2005.
+
+Many people contributed in one or more ways to the final beast, see the file
+CREDITS for an (incomplete) list. If you miss your name, please drop me a
+mail. Thank you!
=cut
https://perl5.git.perl.org / perl5.git / blobdiff