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58cde26e JH |
1 | #!/usr/bin/perl -w |
2 | ||
3 | # mark.biggar@TrustedSysLabs.com | |
4 | ||
5 | # The following hash values are internally used: | |
6 | # _e: exponent (BigInt) | |
7 | # _m: mantissa (absolute BigInt) | |
8 | # sign: +,-,"NaN" if not a number | |
9 | # _a: accuracy | |
10 | # _p: precision | |
11 | # _cow: Copy-On-Write (NRY) | |
12 | ||
a0d0e21e LW |
13 | package Math::BigFloat; |
14 | ||
58cde26e JH |
15 | $VERSION = 1.15; |
16 | require 5.005; | |
17 | use Exporter; | |
18 | use Math::BigInt qw/trace objectify/; | |
19 | @ISA = qw( Exporter Math::BigInt); | |
20 | # can not export bneg/babs since the are only in MBI | |
21 | @EXPORT_OK = qw( | |
22 | bcmp | |
23 | badd bmul bdiv bmod bnorm bsub | |
24 | bgcd blcm bround bfround | |
25 | bpow bnan bzero bfloor bceil | |
26 | bacmp bstr binc bdec bint binf | |
27 | is_odd is_even is_nan is_inf | |
28 | is_zero is_one sign | |
29 | ); | |
a0d0e21e | 30 | |
58cde26e JH |
31 | #@EXPORT = qw( ); |
32 | use strict; | |
33 | use vars qw/$AUTOLOAD $accuracy $precision $div_scale $rnd_mode/; | |
34 | my $class = "Math::BigFloat"; | |
a0d0e21e | 35 | |
a5f75d66 | 36 | use overload |
58cde26e JH |
37 | '<=>' => sub { |
38 | $_[2] ? | |
39 | $class->bcmp($_[1],$_[0]) : | |
40 | $class->bcmp($_[0],$_[1])}, | |
41 | 'int' => sub { $_[0]->copy()->bround(0,'trunc'); }, | |
a5f75d66 | 42 | ; |
a0d0e21e | 43 | |
58cde26e JH |
44 | # are NaNs ok? |
45 | my $NaNOK=1; | |
46 | # set to 1 for tracing | |
47 | my $trace = 0; | |
48 | # constant for easier life | |
49 | my $nan = 'NaN'; | |
50 | my $ten = Math::BigInt->new(10); # shortcut for speed | |
51 | ||
52 | # Rounding modes one of 'even', 'odd', '+inf', '-inf', 'zero' or 'trunc' | |
53 | $rnd_mode = 'even'; | |
54 | $accuracy = undef; | |
55 | $precision = undef; | |
56 | $div_scale = 40; | |
57 | ||
58 | { | |
59 | # checks for AUTOLOAD | |
60 | my %methods = map { $_ => 1 } | |
61 | qw / fadd fsub fmul fdiv fround ffround fsqrt fmod fstr fsstr fpow fnorm | |
62 | fabs fneg fint fcmp fzero fnan finc fdec | |
63 | /; | |
64 | ||
65 | sub method_valid { return exists $methods{$_[0]||''}; } | |
a0d0e21e | 66 | } |
0e8b9368 | 67 | |
58cde26e JH |
68 | ############################################################################## |
69 | # constructors | |
a0d0e21e | 70 | |
58cde26e JH |
71 | sub new |
72 | { | |
73 | # create a new BigFloat object from a string or another bigfloat object. | |
74 | # _e: exponent | |
75 | # _m: mantissa | |
76 | # sign => sign (+/-), or "NaN" | |
a0d0e21e | 77 | |
58cde26e JH |
78 | trace (@_); |
79 | my $class = shift; | |
80 | ||
81 | my $wanted = shift; # avoid numify call by not using || here | |
82 | return $class->bzero() if !defined $wanted; # default to 0 | |
83 | return $wanted->copy() if ref($wanted) eq $class; | |
a0d0e21e | 84 | |
58cde26e JH |
85 | my $round = shift; $round = 0 if !defined $round; # no rounding as default |
86 | my $self = {}; bless $self, $class; | |
87 | #shortcut for bigints | |
88 | if (ref($wanted) eq 'Math::BigInt') | |
89 | { | |
90 | $self->{_m} = $wanted; | |
91 | $self->{_e} = Math::BigInt->new(0); | |
92 | $self->{_m}->babs(); | |
93 | $self->{sign} = $wanted->sign(); | |
94 | return $self; | |
95 | } | |
96 | # got string | |
97 | # handle '+inf', '-inf' first | |
98 | if ($wanted =~ /^[+-]inf$/) | |
99 | { | |
100 | $self->{_e} = Math::BigInt->new(0); | |
101 | $self->{_m} = Math::BigInt->new(0); | |
102 | $self->{sign} = $wanted; | |
103 | return $self; | |
104 | } | |
105 | #print "new string '$wanted'\n"; | |
106 | my ($mis,$miv,$mfv,$es,$ev) = Math::BigInt::_split(\$wanted); | |
107 | if (!ref $mis) | |
108 | { | |
109 | die "$wanted is not a number initialized to $class" if !$NaNOK; | |
110 | $self->{_e} = Math::BigInt->new(0); | |
111 | $self->{_m} = Math::BigInt->new(0); | |
112 | $self->{sign} = $nan; | |
113 | } | |
114 | else | |
115 | { | |
116 | # make integer from mantissa by adjusting exp, then convert to bigint | |
117 | $self->{_e} = Math::BigInt->new("$$es$$ev"); # exponent | |
118 | $self->{_m} = Math::BigInt->new("$$mis$$miv$$mfv"); # create mantissa | |
119 | # 3.123E0 = 3123E-3, and 3.123E-2 => 3123E-5 | |
120 | $self->{_e} -= CORE::length($$mfv); | |
121 | $self->{sign} = $self->{_m}->sign(); $self->{_m}->babs(); | |
122 | } | |
123 | #print "$wanted => $self->{sign} $self->{value}->[0]\n"; | |
124 | $self->bnorm(); # first normalize | |
125 | # if any of the globals is set, round to them and thus store them insid $self | |
126 | $self->round($accuracy,$precision,$rnd_mode) | |
127 | if defined $accuracy || defined $precision; | |
128 | return $self; | |
129 | } | |
a0d0e21e | 130 | |
58cde26e JH |
131 | # some shortcuts for easier life |
132 | sub bfloat | |
133 | { | |
134 | # exportable version of new | |
135 | trace(@_); | |
136 | return $class->new(@_); | |
137 | } | |
138 | ||
139 | sub bint | |
140 | { | |
141 | # exportable version of new | |
142 | trace(@_); | |
143 | return $class->new(@_,0)->bround(0,'trunc'); | |
144 | } | |
145 | ||
146 | sub bnan | |
147 | { | |
148 | # create a bigfloat 'NaN', if given a BigFloat, set it to 'NaN' | |
149 | my $self = shift; | |
150 | $self = $class if !defined $self; | |
151 | if (!ref($self)) | |
288d023a | 152 | { |
58cde26e | 153 | my $c = $self; $self = {}; bless $self, $c; |
a0d0e21e | 154 | } |
58cde26e JH |
155 | $self->{_e} = new Math::BigInt 0; |
156 | $self->{_m} = new Math::BigInt 0; | |
157 | $self->{sign} = $nan; | |
158 | trace('NaN'); | |
159 | return $self; | |
160 | } | |
a0d0e21e | 161 | |
58cde26e JH |
162 | sub binf |
163 | { | |
164 | # create a bigfloat '+-inf', if given a BigFloat, set it to '+-inf' | |
165 | my $self = shift; | |
166 | my $sign = shift; $sign = '+' if !defined $sign || $sign ne '-'; | |
a0d0e21e | 167 | |
58cde26e JH |
168 | $self = $class if !defined $self; |
169 | if (!ref($self)) | |
170 | { | |
171 | my $c = $self; $self = {}; bless $self, $c; | |
172 | } | |
173 | $self->{_e} = new Math::BigInt 0; | |
174 | $self->{_m} = new Math::BigInt 0; | |
175 | $self->{sign} = $sign.'inf'; | |
176 | trace('inf'); | |
177 | return $self; | |
178 | } | |
a0d0e21e | 179 | |
58cde26e JH |
180 | sub bzero |
181 | { | |
182 | # create a bigfloat '+0', if given a BigFloat, set it to 0 | |
183 | my $self = shift; | |
184 | $self = $class if !defined $self; | |
185 | if (!ref($self)) | |
186 | { | |
187 | my $c = $self; $self = {}; bless $self, $c; | |
188 | } | |
189 | $self->{_m} = new Math::BigInt 0; | |
190 | $self->{_e} = new Math::BigInt 1; | |
191 | $self->{sign} = '+'; | |
192 | trace('0'); | |
193 | return $self; | |
194 | } | |
195 | ||
196 | ############################################################################## | |
197 | # string conversation | |
198 | ||
199 | sub bstr | |
200 | { | |
201 | # (ref to BFLOAT or num_str ) return num_str | |
202 | # Convert number from internal format to (non-scientific) string format. | |
203 | # internal format is always normalized (no leading zeros, "-0" => "+0") | |
204 | trace(@_); | |
205 | my ($self,$x) = objectify(1,@_); | |
206 | ||
207 | #return "Oups! e was $nan" if $x->{_e}->{sign} eq $nan; | |
208 | #return "Oups! m was $nan" if $x->{_m}->{sign} eq $nan; | |
209 | return $x->{sign} if $x->{sign} !~ /^[+-]$/; | |
210 | return '0' if $x->is_zero(); | |
211 | ||
212 | my $es = $x->{_m}->bstr(); | |
213 | if ($x->{_e}->is_zero()) | |
214 | { | |
215 | $es = $x->{sign}.$es if $x->{sign} eq '-'; | |
216 | return $es; | |
217 | } | |
218 | ||
219 | if ($x->{_e}->sign() eq '-') | |
220 | { | |
221 | if ($x->{_e} <= -CORE::length($es)) | |
222 | { | |
223 | # print "style: 0.xxxx\n"; | |
224 | my $r = $x->{_e}->copy(); $r->babs()->bsub( CORE::length($es) ); | |
225 | $es = '0.'. ('0' x $r) . $es; | |
226 | } | |
227 | else | |
228 | { | |
229 | # print "insert '.' at $x->{_e} in '$es'\n"; | |
230 | substr($es,$x->{_e},0) = '.'; | |
82cf049f | 231 | } |
82cf049f | 232 | } |
58cde26e JH |
233 | else |
234 | { | |
235 | # expand with zeros | |
236 | $es .= '0' x $x->{_e}; | |
237 | } | |
238 | $es = $x->{sign}.$es if $x->{sign} eq '-'; | |
239 | return $es; | |
82cf049f | 240 | } |
f216259d | 241 | |
58cde26e JH |
242 | sub bsstr |
243 | { | |
244 | # (ref to BFLOAT or num_str ) return num_str | |
245 | # Convert number from internal format to scientific string format. | |
246 | # internal format is always normalized (no leading zeros, "-0E0" => "+0E0") | |
247 | trace(@_); | |
248 | my ($self,$x) = objectify(1,@_); | |
a0d0e21e | 249 | |
58cde26e JH |
250 | return "Oups! e was $nan" if $x->{_e}->{sign} eq $nan; |
251 | return "Oups! m was $nan" if $x->{_m}->{sign} eq $nan; | |
252 | return $x->{sign} if $x->{sign} !~ /^[+-]$/; | |
253 | my $sign = $x->{_e}->{sign}; $sign = '' if $sign eq '-'; | |
254 | my $sep = 'e'.$sign; | |
255 | return $x->{_m}->bstr().$sep.$x->{_e}->bstr(); | |
256 | } | |
257 | ||
258 | sub numify | |
259 | { | |
260 | # Make a number from a BigFloat object | |
261 | # simple return string and let Perl's atoi() handle the rest | |
262 | trace (@_); | |
263 | my ($self,$x) = objectify(1,@_); | |
264 | return $x->bsstr(); | |
265 | } | |
a0d0e21e | 266 | |
58cde26e JH |
267 | ############################################################################## |
268 | # public stuff (usually prefixed with "b") | |
269 | ||
270 | # really? Just for exporting them is not what I had in mind | |
271 | #sub babs | |
272 | # { | |
273 | # $class->SUPER::babs($class,@_); | |
274 | # } | |
275 | #sub bneg | |
276 | # { | |
277 | # $class->SUPER::bneg($class,@_); | |
278 | # } | |
279 | #sub bnot | |
280 | # { | |
281 | # $class->SUPER::bnot($class,@_); | |
282 | # } | |
283 | ||
284 | sub bcmp | |
285 | { | |
286 | # Compares 2 values. Returns one of undef, <0, =0, >0. (suitable for sort) | |
287 | # (BFLOAT or num_str, BFLOAT or num_str) return cond_code | |
288 | my ($self,$x,$y) = objectify(2,@_); | |
289 | return undef if (($x->{sign} eq $nan) || ($y->{sign} eq $nan)); | |
290 | ||
291 | # check sign | |
292 | return 1 if $x->{sign} eq '+' && $y->{sign} eq '-'; | |
293 | return -1 if $x->{sign} eq '-' && $y->{sign} eq '+'; # does also -x <=> 0 | |
294 | ||
295 | return 0 if $x->is_zero() && $y->is_zero(); # 0 <=> 0 | |
296 | return -1 if $x->is_zero() && $y->{sign} eq '+'; # 0 <=> +y | |
297 | return 1 if $y->is_zero() && $x->{sign} eq '+'; # +x <=> 0 | |
298 | ||
299 | # adjust so that exponents are equal | |
300 | my $lx = $x->{_m}->length() + $x->{_e}; | |
301 | my $ly = $y->{_m}->length() + $y->{_e}; | |
302 | # print "x $x y $y lx $lx ly $ly\n"; | |
303 | my $l = $lx - $ly; $l = -$l if $x->{sign} eq '-'; | |
304 | # print "$l $x->{sign}\n"; | |
305 | return $l if $l != 0; | |
306 | ||
307 | # lens are equal, so compare mantissa, if equal, compare exponents | |
308 | # this assumes normaized numbers (no trailing zeros etc) | |
309 | my $rc = $x->{_m} <=> $y->{_m} || $x->{_e} <=> $y->{_e}; | |
310 | $rc = -$rc if $x->{sign} eq '-'; # -124 < -123 | |
311 | return $rc; | |
312 | } | |
313 | ||
314 | sub bacmp | |
315 | { | |
316 | # Compares 2 values, ignoring their signs. | |
317 | # Returns one of undef, <0, =0, >0. (suitable for sort) | |
318 | # (BFLOAT or num_str, BFLOAT or num_str) return cond_code | |
319 | my ($self,$x,$y) = objectify(2,@_); | |
320 | return undef if (($x->{sign} eq $nan) || ($y->{sign} eq $nan)); | |
321 | ||
322 | # signs are ignored, so check length | |
323 | # length(x) is length(m)+e aka length of non-fraction part | |
324 | # the longer one is bigger | |
325 | my $l = $x->length() - $y->length(); | |
326 | #print "$l\n"; | |
327 | return $l if $l != 0; | |
328 | #print "equal lengths\n"; | |
329 | ||
330 | # if both are equal long, make full compare | |
331 | # first compare only the mantissa | |
332 | # if mantissa are equal, compare fractions | |
333 | ||
334 | return $x->{_m} <=> $y->{_m} || $x->{_e} <=> $y->{_e}; | |
335 | } | |
a0d0e21e | 336 | |
58cde26e JH |
337 | sub badd |
338 | { | |
339 | # add second arg (BFLOAT or string) to first (BFLOAT) (modifies first) | |
340 | # return result as BFLOAT | |
341 | trace(@_); | |
342 | my ($self,$x,$y,$a,$p,$r) = objectify(2,@_); | |
343 | ||
344 | #print "add $x ",ref($x)," $y ",ref($y),"\n"; | |
345 | return $x->bnan() if (($x->{sign} eq $nan) || ($y->{sign} eq $nan)); | |
346 | ||
347 | # speed: no add for 0+y or x+0 | |
348 | return $x if $y->is_zero(); # x+0 | |
349 | if ($x->is_zero()) # 0+y | |
350 | { | |
351 | # make copy, clobbering up x (modify in place!) | |
352 | $x->{_e} = $y->{_e}->copy(); | |
353 | $x->{_m} = $y->{_m}->copy(); | |
354 | $x->{sign} = $y->{sign} || $nan; | |
355 | return $x->round($a,$p,$r,$y); | |
a0d0e21e | 356 | } |
58cde26e JH |
357 | |
358 | # take lower of the two e's and adapt m1 to it to match m2 | |
359 | my $e = $y->{_e}; $e = Math::BigInt::bzero() if !defined $e; # if no BFLOAT | |
360 | $e = $e - $x->{_e}; | |
361 | my $add = $y->{_m}->copy(); | |
362 | if ($e < 0) | |
363 | { | |
364 | #print "e < 0\n"; | |
365 | #print "\$x->{_m}: $x->{_m} "; | |
366 | #print "\$x->{_e}: $x->{_e}\n"; | |
367 | my $e1 = $e->copy()->babs(); | |
368 | $x->{_m} *= (10 ** $e1); | |
369 | $x->{_e} += $e; # need the sign of e | |
370 | #$x->{_m} += $y->{_m}; | |
371 | #print "\$x->{_m}: $x->{_m} "; | |
372 | #print "\$x->{_e}: $x->{_e}\n"; | |
373 | } | |
374 | elsif ($e > 0) | |
375 | { | |
376 | #print "e > 0\n"; | |
377 | #print "\$x->{_m}: $x->{_m} \$y->{_m}: $y->{_m} \$e: $e ",ref($e),"\n"; | |
378 | $add *= (10 ** $e); | |
379 | #$x->{_m} += $y->{_m} * (10 ** $e); | |
380 | #print "\$x->{_m}: $x->{_m}\n"; | |
381 | } | |
382 | # else: both e are same, so leave them | |
383 | #print "badd $x->{sign}$x->{_m} + $y->{sign}$add\n"; | |
384 | # fiddle with signs | |
385 | $x->{_m}->{sign} = $x->{sign}; | |
386 | $add->{sign} = $y->{sign}; | |
387 | # finally do add/sub | |
388 | $x->{_m} += $add; | |
389 | # re-adjust signs | |
390 | $x->{sign} = $x->{_m}->{sign}; | |
391 | $x->{_m}->{sign} = '+'; | |
392 | return $x->round($a,$p,$r,$y); | |
393 | } | |
394 | ||
395 | sub bsub | |
396 | { | |
397 | # (BINT or num_str, BINT or num_str) return num_str | |
398 | # subtract second arg from first, modify first | |
399 | my ($self,$x,$y) = objectify(2,@_); | |
a0d0e21e | 400 | |
58cde26e JH |
401 | trace(@_); |
402 | $x->badd($y->bneg()); # badd does not leave internal zeros | |
403 | $y->bneg(); # refix y, assumes no one reads $y in between | |
404 | return $x; | |
405 | } | |
406 | ||
407 | sub binc | |
408 | { | |
409 | # increment arg by one | |
410 | my ($self,$x,$a,$p,$r) = objectify(1,@_); | |
411 | trace(@_); | |
412 | $x->badd($self->_one())->round($a,$p,$r); | |
413 | } | |
414 | ||
415 | sub bdec | |
416 | { | |
417 | # decrement arg by one | |
418 | my ($self,$x,$a,$p,$r) = objectify(1,@_); | |
419 | trace(@_); | |
420 | $x->badd($self->_one('-'))->round($a,$p,$r); | |
421 | } | |
422 | ||
423 | sub blcm | |
424 | { | |
425 | # (BINT or num_str, BINT or num_str) return BINT | |
426 | # does not modify arguments, but returns new object | |
427 | # Lowest Common Multiplicator | |
428 | trace(@_); | |
429 | ||
430 | my ($self,@arg) = objectify(0,@_); | |
431 | my $x = $self->new(shift @arg); | |
432 | while (@arg) { $x = _lcm($x,shift @arg); } | |
433 | $x; | |
434 | } | |
435 | ||
436 | sub bgcd | |
437 | { | |
438 | # (BINT or num_str, BINT or num_str) return BINT | |
439 | # does not modify arguments, but returns new object | |
440 | # GCD -- Euclids algorithm Knuth Vol 2 pg 296 | |
441 | trace(@_); | |
442 | ||
443 | my ($self,@arg) = objectify(0,@_); | |
444 | my $x = $self->new(shift @arg); | |
445 | while (@arg) { $x = _gcd($x,shift @arg); } | |
446 | $x; | |
447 | } | |
448 | ||
449 | sub is_zero | |
450 | { | |
451 | # return true if arg (BINT or num_str) is zero (array '+', '0') | |
452 | my $x = shift; $x = $class->new($x) unless ref $x; | |
453 | #my ($self,$x) = objectify(1,@_); | |
454 | trace(@_); | |
455 | return ($x->{sign} ne $nan && $x->{_m}->is_zero()); | |
456 | } | |
457 | ||
458 | sub is_one | |
459 | { | |
460 | # return true if arg (BINT or num_str) is +1 (array '+', '1') | |
461 | # or -1 if signis given | |
462 | my $x = shift; $x = $class->new($x) unless ref $x; | |
463 | #my ($self,$x) = objectify(1,@_); | |
464 | my $sign = $_[2] || '+'; | |
465 | return ($x->{sign} eq $sign && $x->{_e}->is_zero() && $x->{_m}->is_one()); | |
466 | } | |
467 | ||
468 | sub is_odd | |
469 | { | |
470 | # return true if arg (BINT or num_str) is odd or -1 if even | |
471 | my $x = shift; $x = $class->new($x) unless ref $x; | |
472 | #my ($self,$x) = objectify(1,@_); | |
473 | return ($x->{sign} ne $nan && $x->{_e}->is_zero() && $x->{_m}->is_odd()); | |
474 | } | |
475 | ||
476 | sub is_even | |
477 | { | |
478 | # return true if arg (BINT or num_str) is even or -1 if odd | |
479 | my $x = shift; $x = $class->new($x) unless ref $x; | |
480 | #my ($self,$x) = objectify(1,@_); | |
481 | return 0 if $x->{sign} eq $nan; # NaN isn't | |
482 | return 1 if $x->{_m}->is_zero(); # 0 is | |
483 | return ($x->{_e}->is_zero() && $x->{_m}->is_even()); | |
484 | } | |
485 | ||
486 | sub bmul | |
487 | { | |
488 | # multiply two numbers -- stolen from Knuth Vol 2 pg 233 | |
489 | # (BINT or num_str, BINT or num_str) return BINT | |
490 | my ($self,$x,$y,$a,$p,$r) = objectify(2,@_); | |
491 | # trace(@_); | |
492 | ||
493 | #print "mul $x->{_m}e$x->{_e} $y->{_m}e$y->{_e}\n"; | |
494 | return $x->bnan() if (($x->{sign} eq $nan) || ($y->{sign} eq $nan)); | |
495 | ||
496 | # print "$x $y\n"; | |
497 | # aEb * cEd = (a*c)E(b+d) | |
498 | $x->{_m} = $x->{_m} * $y->{_m}; | |
499 | #print "m: $x->{_m}\n"; | |
500 | $x->{_e} = $x->{_e} + $y->{_e}; | |
501 | #print "e: $x->{_m}\n"; | |
502 | # adjust sign: | |
503 | $x->{sign} = $x->{sign} ne $y->{sign} ? '-' : '+'; | |
504 | #print "s: $x->{sign}\n"; | |
505 | return $x->round($a,$p,$r,$y); | |
506 | } | |
507 | ||
508 | sub bdiv | |
509 | { | |
510 | # (dividend: BFLOAT or num_str, divisor: BFLOAT or num_str) return | |
511 | # (BFLOAT,BFLOAT) (quo,rem) or BINT (only rem) | |
512 | my ($self,$x,$y,$a,$p,$r) = objectify(2,@_); | |
513 | ||
514 | return wantarray ? ($x->bnan(),bnan()) : $x->bnan() | |
515 | if ($x->{sign} eq $nan || $y->is_nan() || $y->is_zero()); | |
516 | ||
517 | # we need to limit the accuracy to protect against overflow | |
518 | my ($scale,$mode) = $x->_scale_a($accuracy,$rnd_mode,$a,$r); # ignore $p | |
519 | my $add = 1; # for proper rounding | |
520 | my $fallback = 0; | |
521 | if (!defined $scale) | |
522 | { | |
523 | $fallback = 1; $scale = $div_scale; # simulate old behaviour | |
a0d0e21e | 524 | } |
58cde26e JH |
525 | #print "div_scale $div_scale\n"; |
526 | my $lx = $x->{_m}->length(); | |
527 | $scale = $lx if $lx > $scale; | |
528 | my $ly = $y->{_m}->length(); | |
529 | $scale = $ly if $ly > $scale; | |
530 | #print "scale $scale $lx $ly\n"; | |
531 | #$scale = $scale - $lx + $ly; | |
532 | #print "scale $scale\n"; | |
533 | $scale += $add; # calculate some more digits for proper rounding | |
a0d0e21e | 534 | |
58cde26e | 535 | # print "bdiv $x $y scale $scale xl $lx yl $ly\n"; |
a0d0e21e | 536 | |
58cde26e JH |
537 | return wantarray ? ($x,$self->bzero()) : $x if $x->is_zero(); |
538 | ||
539 | $x->{sign} = $x->{sign} ne $y->sign() ? '-' : '+'; | |
a0d0e21e | 540 | |
58cde26e JH |
541 | # check for / +-1 ( +/- 1E0) |
542 | if ($y->is_one()) | |
543 | { | |
544 | return wantarray ? ($x,$self->bzero()) : $x; | |
a0d0e21e | 545 | } |
a5f75d66 | 546 | |
58cde26e JH |
547 | # a * 10 ** b / c * 10 ** d => a/c * 10 ** (b-d) |
548 | #print "self: $self x: $x ref(x) ", ref($x)," m: $x->{_m}\n"; | |
549 | # my $scale_10 = 10 ** $scale; $x->{_m}->bmul($scale_10); | |
550 | $x->{_m}->blsft($scale,10); | |
551 | #print "m: $x->{_m}\n"; | |
552 | $x->{_m}->bdiv( $y->{_m} ); # a/c | |
553 | #print "m: $x->{_m}\n"; | |
554 | #print "e: $x->{_e} $y->{_e}",$scale,"\n"; | |
555 | $x->{_e}->bsub($y->{_e}); # b-d | |
556 | #print "e: $x->{_e}\n"; | |
557 | $x->{_e}->bsub($scale); # correct for 10**scale | |
558 | #print "e: $x->{_e}\n"; | |
559 | $x->bnorm(); # remove trailing zeros | |
560 | ||
561 | # print "round $x to -$scale (-$add) mode $mode\n"; | |
562 | #print "$x ",scalar ref($x), "=> $t",scalar ref($t),"\n"; | |
563 | if ($fallback) | |
564 | { | |
565 | $scale -= $add; $x->round($scale,undef,$r); # round to less | |
a0d0e21e | 566 | } |
58cde26e JH |
567 | else |
568 | { | |
569 | return $x->round($a,$p,$r,$y); | |
570 | } | |
571 | if (wantarray) | |
572 | { | |
573 | my $rem = $x->copy(); | |
574 | $rem->bmod($y,$a,$p,$r); | |
575 | return ($x,$rem->round($scale,undef,$r)) if $fallback; | |
576 | return ($x,$rem->round($a,$p,$r,$y)); | |
577 | } | |
578 | return $x; | |
579 | } | |
a0d0e21e | 580 | |
58cde26e JH |
581 | sub bmod |
582 | { | |
583 | # (dividend: BFLOAT or num_str, divisor: BFLOAT or num_str) return reminder | |
584 | my ($self,$x,$y,$a,$p,$r) = objectify(2,@_); | |
a0d0e21e | 585 | |
58cde26e JH |
586 | return $x->bnan() if ($x->{sign} eq $nan || $y->is_nan() || $y->is_zero()); |
587 | return $x->bzero() if $y->is_one(); | |
588 | ||
589 | # XXX tels: not done yet | |
590 | return $x->round($a,$p,$r,$y); | |
591 | } | |
592 | ||
593 | sub bsqrt | |
594 | { | |
595 | # calculate square root | |
596 | # this should use a different test to see wether the accuracy we want is... | |
597 | my ($self,$x,$a,$p,$r) = objectify(1,@_); | |
598 | ||
599 | # we need to limit the accuracy to protect against overflow | |
600 | my ($scale,$mode) = $x->_scale_a($accuracy,$rnd_mode,$a,$r); # ignore $p | |
601 | $scale = $div_scale if (!defined $scale); # simulate old behaviour | |
602 | # print "scale $scale\n"; | |
603 | ||
604 | return $x->bnan() if ($x->sign() eq '-') || ($x->sign() eq $nan); | |
605 | return $x if $x->is_zero() || $x == 1; | |
606 | ||
607 | my $len = $x->{_m}->length(); | |
608 | $scale = $len if $scale < $len; | |
609 | print "scale $scale\n"; | |
610 | $scale += 1; # because we need more than $scale to later round | |
611 | my $e = Math::BigFloat->new("1E-$scale"); # make test variable | |
612 | return $x->bnan() if $e->sign() eq 'NaN'; | |
613 | ||
614 | # print "$scale $e\n"; | |
615 | ||
616 | my $gs = Math::BigFloat->new(100); # first guess | |
617 | my $org = $x->copy(); | |
618 | ||
619 | # start with some reasonable guess | |
620 | #$x *= 10 ** ($len - $org->{_e}); | |
621 | #$x /= 2; | |
622 | #my $gs = Math::BigFloat->new(1); | |
623 | # print "first guess: $gs (x $x)\n"; | |
624 | ||
625 | my $diff = $e; | |
626 | my $y = $x->copy(); | |
627 | my $two = Math::BigFloat->new(2); | |
628 | $x = Math::BigFloat->new($x) if ref($x) ne $class; # promote BigInts | |
629 | # $scale = 2; | |
630 | while ($diff >= $e) | |
631 | { | |
632 | #sleep(1); | |
633 | return $x->bnan() if $gs->is_zero(); | |
634 | #my $r = $y / $gs; | |
635 | #print "$y / $gs = ",$r," ref(\$r) ",ref($r),"\n"; | |
636 | my $r = $y->copy(); $r->bdiv($gs,$scale); # $scale); | |
637 | $x = ($r + $gs); | |
638 | $x->bdiv($two,$scale); # $scale *= 2; | |
639 | $diff = $x->copy()->bsub($gs)->babs(); | |
640 | #print "gs: $gs x: $x \n"; | |
641 | $gs = $x->copy(); | |
642 | # print "$x $org $scale $gs\n"; | |
643 | #$gs *= 2; | |
644 | #$y = $org->copy(); | |
645 | #$x += $y->bdiv($x, $scale); # need only $gs scale | |
646 | # $y = $org->copy(); | |
647 | #$x /= 2; | |
648 | print "x $x diff $diff $e\n"; | |
a0d0e21e | 649 | } |
58cde26e JH |
650 | $x->bnorm($scale-1,undef,$mode); |
651 | } | |
a5f75d66 | 652 | |
58cde26e JH |
653 | sub _set |
654 | { | |
655 | # set to a specific 'small' value, internal usage | |
656 | my $x = shift; | |
657 | my $v = shift||0; | |
658 | ||
659 | $x->{sign} = $nan, return if $v !~ /^[-+]?[0-9]+$/; | |
660 | $x->{_m}->{value} = [abs($v)]; | |
661 | $x->{_e}->{value} = [0]; | |
662 | $x->{sign} = '+'; $x->{sign} = '-' if $v < 0; | |
663 | return $x; | |
664 | } | |
665 | ||
666 | sub bpow | |
667 | { | |
668 | # (BFLOAT or num_str, BFLOAT or num_str) return BFLOAT | |
669 | # compute power of two numbers, second arg is used as integer | |
670 | # modifies first argument | |
671 | ||
672 | my ($self,$x,$y,$a,$p,$r) = objectify(2,@_); | |
673 | ||
674 | return $x->bnan() if $x->{sign} eq $nan || $y->{sign} eq $nan; | |
675 | return $x->_one() if $y->is_zero(); | |
676 | return $x if $x->is_one() || $y->is_one(); | |
677 | my $y1 = $y->as_number(); # make bigint | |
678 | if ($x == -1) | |
679 | { | |
680 | # if $x == -1 and odd/even y => +1/-1 because +-1 ^ (+-1) => +-1 | |
681 | return $y1->is_odd() ? $x : $x->_set(1); # $x->babs() would work to | |
288d023a | 682 | } |
58cde26e JH |
683 | return $x if $x->is_zero() && $y->{sign} eq '+'; # 0**y => 0 (if not y <= 0) |
684 | # 0 ** -y => 1 / (0 ** y) => / 0! | |
685 | return $x->bnan() if $x->is_zero() && $y->{sign} eq '-'; | |
686 | ||
687 | # calculate $x->{_m} ** $y and $x->{_e} * $y separately (faster) | |
688 | $y1->babs(); | |
689 | $x->{_m}->bpow($y1); | |
690 | $x->{_e}->bmul($y1); | |
691 | $x->{sign} = $nan if $x->{_m}->{sign} eq $nan || $x->{_e}->{sign} eq $nan; | |
692 | $x->bnorm(); | |
693 | if ($y->{sign} eq '-') | |
694 | { | |
695 | # modify $x in place! | |
696 | my $z = $x->copy(); $x->_set(1); | |
697 | return $x->bdiv($z,$a,$p,$r); # round in one go (might ignore y's A!) | |
a0d0e21e | 698 | } |
58cde26e JH |
699 | return $x->round($a,$p,$r,$y); |
700 | } | |
701 | ||
702 | ############################################################################### | |
703 | # rounding functions | |
704 | ||
705 | sub bfround | |
706 | { | |
707 | # precision: round to the $Nth digit left (+$n) or right (-$n) from the '.' | |
708 | # $n == 0 means round to integer | |
709 | # expects and returns normalized numbers! | |
710 | my $x = shift; $x = $class->new($x) unless ref $x; | |
a0d0e21e | 711 | |
58cde26e JH |
712 | return $x if $x->modify('bfround'); |
713 | ||
714 | my ($scale,$mode) = $x->_scale_p($precision,$rnd_mode,@_); | |
715 | return $x if !defined $scale; # no-op | |
716 | ||
717 | # print "MBF bfround $x to scale $scale mode $mode\n"; | |
718 | return $x if $x->is_nan() or $x->is_zero(); | |
719 | ||
720 | if ($scale < 0) | |
721 | { | |
722 | # print "bfround scale $scale e $x->{_e}\n"; | |
723 | # round right from the '.' | |
724 | return $x if $x->{_e} >= 0; # nothing to round | |
725 | $scale = -$scale; # positive for simplicity | |
726 | my $len = $x->{_m}->length(); # length of mantissa | |
727 | my $dad = -$x->{_e}; # digits after dot | |
728 | my $zad = 0; # zeros after dot | |
729 | $zad = -$len-$x->{_e} if ($x->{_e} < -$len);# for 0.00..00xxx style | |
730 | # print "scale $scale dad $dad zad $zad len $len\n"; | |
731 | ||
732 | # number bsstr len zad dad | |
733 | # 0.123 123e-3 3 0 3 | |
734 | # 0.0123 123e-4 3 1 4 | |
735 | # 0.001 1e-3 1 2 3 | |
736 | # 1.23 123e-2 3 0 2 | |
737 | # 1.2345 12345e-4 5 0 4 | |
738 | ||
739 | # do not round after/right of the $dad | |
740 | return $x if $scale > $dad; # 0.123, scale >= 3 => exit | |
741 | ||
742 | # round to zero if rounding inside the $zad, but not for last zero like: | |
743 | # 0.0065, scale -2, round last '0' with following '65' (scale == zad case) | |
744 | if ($scale < $zad) | |
745 | { | |
746 | $x->{_m} = Math::BigInt->new(0); | |
747 | $x->{_e} = Math::BigInt->new(1); | |
748 | $x->{sign} = '+'; | |
749 | return $x; | |
750 | } | |
751 | if ($scale == $zad) # for 0.006, scale -2 and trunc | |
752 | { | |
753 | $scale = -$len; | |
754 | } | |
755 | else | |
756 | { | |
757 | # adjust round-point to be inside mantissa | |
758 | if ($zad != 0) | |
759 | { | |
760 | $scale = $scale-$zad; | |
761 | } | |
762 | else | |
763 | { | |
764 | my $dbd = $len - $dad; $dbd = 0 if $dbd < 0; # digits before dot | |
765 | $scale = $dbd+$scale; | |
766 | } | |
767 | } | |
768 | # print "round to $x->{_m} to $scale\n"; | |
a0d0e21e | 769 | } |
58cde26e JH |
770 | else |
771 | { | |
772 | # 123 => 100 means length(123) = 3 - $scale (2) => 1 | |
a5f75d66 | 773 | |
58cde26e JH |
774 | # calculate digits before dot |
775 | my $dbt = $x->{_m}->length(); $dbt += $x->{_e} if $x->{_e}->sign() eq '-'; | |
776 | if (($scale > $dbt) && ($dbt < 0)) | |
777 | { | |
778 | # if not enough digits before dot, round to zero | |
779 | $x->{_m} = Math::BigInt->new(0); | |
780 | $x->{_e} = Math::BigInt->new(1); | |
781 | $x->{sign} = '+'; | |
782 | return $x; | |
783 | } | |
784 | if (($scale >= 0) && ($dbt == 0)) | |
785 | { | |
786 | # 0.49->bfround(1): scale == 1, dbt == 0: => 0.0 | |
787 | # 0.51->bfround(0): scale == 0, dbt == 0: => 1.0 | |
788 | # 0.5->bfround(0): scale == 0, dbt == 0: => 0 | |
789 | # 0.05->bfround(0): scale == 0, dbt == 0: => 0 | |
790 | # print "$scale $dbt $x->{_m}\n"; | |
791 | $scale = -$x->{_m}->length(); | |
792 | } | |
793 | elsif ($dbt > 0) | |
794 | { | |
795 | # correct by subtracting scale | |
796 | $scale = $dbt - $scale; | |
797 | } | |
798 | else | |
799 | { | |
800 | $scale = $x->{_m}->length() - $scale; | |
801 | } | |
a0d0e21e | 802 | } |
58cde26e JH |
803 | #print "using $scale for $x->{_m} with '$mode'\n"; |
804 | # pass sign to bround for '+inf' and '-inf' rounding modes | |
805 | $x->{_m}->{sign} = $x->{sign}; | |
806 | $x->{_m}->bround($scale,$mode); | |
807 | $x->{_m}->{sign} = '+'; # fix sign back | |
808 | $x->bnorm(); | |
809 | } | |
810 | ||
811 | sub bround | |
812 | { | |
813 | # accuracy: preserve $N digits, and overwrite the rest with 0's | |
814 | my $x = shift; $x = $class->new($x) unless ref $x; | |
815 | my ($scale,$mode) = $x->_scale_a($accuracy,$rnd_mode,@_); | |
816 | return $x if !defined $scale; # no-op | |
817 | ||
818 | return $x if $x->modify('bround'); | |
819 | ||
820 | # print "bround $scale $mode\n"; | |
821 | # 0 => return all digits, scale < 0 makes no sense | |
822 | return $x if ($scale <= 0); | |
823 | return $x if $x->is_nan() or $x->is_zero(); # never round a 0 | |
824 | ||
825 | # if $e longer than $m, we have 0.0000xxxyyy style number, and must | |
826 | # subtract the delta from scale, to simulate keeping the zeros | |
827 | # -5 +5 => 1; -10 +5 => -4 | |
828 | my $delta = $x->{_e} + $x->{_m}->length() + 1; | |
829 | # removed by tlr, since causes problems with fraction tests: | |
830 | # $scale += $delta if $delta < 0; | |
831 | ||
832 | # if we should keep more digits than the mantissa has, do nothing | |
833 | return $x if $x->{_m}->length() <= $scale; | |
f216259d | 834 | |
58cde26e JH |
835 | # pass sign to bround for '+inf' and '-inf' rounding modes |
836 | $x->{_m}->{sign} = $x->{sign}; | |
837 | $x->{_m}->bround($scale,$mode); # round mantissa | |
838 | $x->{_m}->{sign} = '+'; # fix sign back | |
839 | return $x->bnorm(); # del trailing zeros gen. by bround() | |
840 | } | |
841 | ||
842 | sub bfloor | |
843 | { | |
844 | # return integer less or equal then $x | |
845 | my ($self,$x,$a,$p,$r) = objectify(1,@_); | |
846 | ||
847 | return $x if $x->modify('bfloor'); | |
848 | ||
849 | return $x if $x->{sign} !~ /^[+-]$/; # nan, +inf, -inf | |
850 | ||
851 | # if $x has digits after dot | |
852 | if ($x->{_e}->{sign} eq '-') | |
853 | { | |
854 | $x->{_m}->brsft(-$x->{_e},10); | |
855 | $x->{_e}->bzero(); | |
856 | $x-- if $x->{sign} eq '-'; | |
f216259d | 857 | } |
58cde26e JH |
858 | return $x->round($a,$p,$r); |
859 | } | |
288d023a | 860 | |
58cde26e JH |
861 | sub bceil |
862 | { | |
863 | # return integer greater or equal then $x | |
864 | my ($self,$x,$a,$p,$r) = objectify(1,@_); | |
865 | ||
866 | return $x if $x->modify('bceil'); | |
867 | return $x if $x->{sign} !~ /^[+-]$/; # nan, +inf, -inf | |
868 | ||
869 | # if $x has digits after dot | |
870 | if ($x->{_e}->{sign} eq '-') | |
871 | { | |
872 | $x->{_m}->brsft(-$x->{_e},10); | |
873 | $x->{_e}->bzero(); | |
874 | $x++ if $x->{sign} eq '+'; | |
a0d0e21e | 875 | } |
58cde26e JH |
876 | return $x->round($a,$p,$r); |
877 | } | |
878 | ||
879 | ############################################################################### | |
a5f75d66 | 880 | |
58cde26e JH |
881 | sub DESTROY |
882 | { | |
883 | # going trough AUTOLOAD for every DESTROY is costly, so avoid it by empty sub | |
884 | } | |
885 | ||
886 | sub AUTOLOAD | |
887 | { | |
888 | # make fxxx and bxxx work | |
889 | # my $self = $_[0]; | |
890 | my $name = $AUTOLOAD; | |
891 | ||
892 | $name =~ s/.*:://; # split package | |
893 | #print "$name\n"; | |
894 | if (!method_valid($name)) | |
895 | { | |
896 | #no strict 'refs'; | |
897 | ## try one level up | |
898 | #&{$class."::SUPER->$name"}(@_); | |
899 | # delayed load of Carp and avoid recursion | |
900 | require Carp; | |
901 | Carp::croak ("Can't call $class\-\>$name, not a valid method"); | |
a0d0e21e | 902 | } |
58cde26e JH |
903 | no strict 'refs'; |
904 | my $bname = $name; $bname =~ s/^f/b/; | |
905 | *{$class."\:\:$name"} = \&$bname; | |
906 | &$bname; # uses @_ | |
907 | } | |
908 | ||
909 | sub exponent | |
910 | { | |
911 | # return a copy of the exponent | |
912 | my $self = shift; | |
913 | $self = $class->new($self) unless ref $self; | |
914 | ||
915 | return bnan() if $self->is_nan(); | |
916 | return $self->{_e}->copy(); | |
917 | } | |
918 | ||
919 | sub mantissa | |
920 | { | |
921 | # return a copy of the mantissa | |
922 | my $self = shift; | |
923 | $self = $class->new($self) unless ref $self; | |
924 | ||
925 | return bnan() if $self->is_nan(); | |
926 | my $m = $self->{_m}->copy(); # faster than going via bstr() | |
927 | $m->bneg() if $self->{sign} eq '-'; | |
928 | ||
929 | return $m; | |
930 | } | |
931 | ||
932 | sub parts | |
933 | { | |
934 | # return a copy of both the exponent and the mantissa | |
935 | my $self = shift; | |
936 | $self = $class->new($self) unless ref $self; | |
937 | ||
938 | return (bnan(),bnan()) if $self->is_nan(); | |
939 | my $m = $self->{_m}->copy(); # faster than going via bstr() | |
940 | $m->bneg() if $self->{sign} eq '-'; | |
941 | return ($m,$self->{_e}->copy()); | |
942 | } | |
943 | ||
944 | ############################################################################## | |
945 | # private stuff (internal use only) | |
946 | ||
947 | sub _one | |
948 | { | |
949 | # internal speedup, set argument to 1, or create a +/- 1 | |
950 | # uses internal knowledge about MBI, thus (bad) | |
951 | my $self = shift; | |
952 | my $x = $self->bzero(); | |
953 | $x->{_m}->{value} = [ 1 ]; $x->{_m}->{sign} = '+'; | |
954 | $x->{_e}->{value} = [ 0 ]; $x->{_e}->{sign} = '+'; | |
955 | $x->{sign} = shift || '+'; | |
956 | return $x; | |
957 | } | |
958 | ||
959 | sub import | |
960 | { | |
961 | my $self = shift; | |
962 | #print "import $self\n"; | |
963 | for ( my $i = 0; $i < @_ ; $i++ ) | |
964 | { | |
965 | if ( $_[$i] eq ':constant' ) | |
966 | { | |
967 | # this rest causes overlord er load to step in | |
968 | # print "overload @_\n"; | |
969 | overload::constant float => sub { $self->new(shift); }; | |
970 | splice @_, $i, 1; last; | |
971 | } | |
972 | } | |
973 | # any non :constant stuff is handled by our parent, Exporter | |
974 | # even if @_ is empty, to give it a chance | |
975 | #$self->SUPER::import(@_); # does not work (would call MBI) | |
976 | $self->export_to_level(1,$self,@_); # need this instead | |
977 | } | |
978 | ||
979 | sub bnorm | |
980 | { | |
981 | # adjust m and e so that m is smallest possible | |
982 | # round number according to accuracy and precision settings | |
983 | my $x = shift; | |
984 | ||
985 | return $x if $x->is_nan(); | |
986 | ||
987 | my $zeros = $x->{_m}->_trailing_zeros(); # correct for trailing zeros | |
988 | if ($zeros != 0) | |
989 | { | |
990 | $x->{_m}->brsft($zeros,10); $x->{_e} += $zeros; | |
991 | } | |
992 | # for something like 0Ey, set y to 1 | |
993 | $x->{_e}->bzero()->binc() if $x->{_m}->is_zero(); | |
994 | return $x->SUPER::bnorm(@_); # call MBI bnorm for round | |
995 | } | |
996 | ||
997 | ############################################################################## | |
998 | # internal calculation routines | |
999 | ||
1000 | sub as_number | |
1001 | { | |
1002 | # return a bigint representation of this BigFloat number | |
1003 | my ($self,$x) = objectify(1,@_); | |
1004 | ||
1005 | my $z; | |
1006 | if ($x->{_e}->is_zero()) | |
1007 | { | |
1008 | $z = $x->{_m}->copy(); | |
1009 | $z->{sign} = $x->{sign}; | |
1010 | return $z; | |
1011 | } | |
1012 | if ($x->{_e} < 0) | |
1013 | { | |
1014 | $x->{_e}->babs(); | |
1015 | my $y = $x->{_m} / ($ten ** $x->{_e}); | |
1016 | $x->{_e}->bneg(); | |
1017 | $y->{sign} = $x->{sign}; | |
1018 | return $y; | |
1019 | } | |
1020 | $z = $x->{_m} * ($ten ** $x->{_e}); | |
1021 | $z->{sign} = $x->{sign}; | |
1022 | return $z; | |
1023 | } | |
1024 | ||
1025 | sub length | |
1026 | { | |
1027 | my $x = shift; $x = $class->new($x) unless ref $x; | |
1028 | ||
1029 | my $len = $x->{_m}->length(); | |
1030 | $len += $x->{_e} if $x->{_e}->sign() eq '+'; | |
1031 | if (wantarray()) | |
1032 | { | |
1033 | my $t = Math::BigInt::bzero(); | |
1034 | $t = $x->{_e}->copy()->babs() if $x->{_e}->sign() eq '-'; | |
1035 | return ($len,$t); | |
1036 | } | |
1037 | return $len; | |
1038 | } | |
a0d0e21e LW |
1039 | |
1040 | 1; | |
a5f75d66 AD |
1041 | __END__ |
1042 | ||
1043 | =head1 NAME | |
1044 | ||
58cde26e | 1045 | Math::BigFloat - Arbitrary size floating point math package |
a5f75d66 AD |
1046 | |
1047 | =head1 SYNOPSIS | |
1048 | ||
a2008d6d | 1049 | use Math::BigFloat; |
58cde26e JH |
1050 | |
1051 | # Number creation | |
1052 | $x = Math::BigInt->new($str); # defaults to 0 | |
1053 | $nan = Math::BigInt->bnan(); # create a NotANumber | |
1054 | $zero = Math::BigInt->bzero();# create a "+0" | |
1055 | ||
1056 | # Testing | |
1057 | $x->is_zero(); # return whether arg is zero or not | |
1058 | $x->is_one(); # return true if arg is +1 | |
1059 | $x->is_one('-'); # return true if arg is -1 | |
1060 | $x->is_odd(); # return true if odd, false for even | |
1061 | $x->is_even(); # return true if even, false for odd | |
1062 | $x->bcmp($y); # compare numbers (undef,<0,=0,>0) | |
1063 | $x->bacmp($y); # compare absolutely (undef,<0,=0,>0) | |
1064 | $x->sign(); # return the sign, either +,- or NaN | |
1065 | ||
1066 | # The following all modify their first argument: | |
1067 | ||
1068 | # set | |
1069 | $x->bzero(); # set $i to 0 | |
1070 | $x->bnan(); # set $i to NaN | |
1071 | ||
1072 | $x->bneg(); # negation | |
1073 | $x->babs(); # absolute value | |
1074 | $x->bnorm(); # normalize (no-op) | |
1075 | $x->bnot(); # two's complement (bit wise not) | |
1076 | $x->binc(); # increment x by 1 | |
1077 | $x->bdec(); # decrement x by 1 | |
1078 | ||
1079 | $x->badd($y); # addition (add $y to $x) | |
1080 | $x->bsub($y); # subtraction (subtract $y from $x) | |
1081 | $x->bmul($y); # multiplication (multiply $x by $y) | |
1082 | $x->bdiv($y); # divide, set $i to quotient | |
1083 | # return (quo,rem) or quo if scalar | |
1084 | ||
1085 | $x->bmod($y); # modulus | |
1086 | $x->bpow($y); # power of arguments (a**b) | |
1087 | $x->blsft($y); # left shift | |
1088 | $x->brsft($y); # right shift | |
1089 | # return (quo,rem) or quo if scalar | |
1090 | ||
1091 | $x->band($y); # bit-wise and | |
1092 | $x->bior($y); # bit-wise inclusive or | |
1093 | $x->bxor($y); # bit-wise exclusive or | |
1094 | $x->bnot(); # bit-wise not (two's complement) | |
1095 | ||
1096 | $x->bround($N); # accuracy: preserver $N digits | |
1097 | $x->bfround($N); # precision: round to the $Nth digit | |
1098 | ||
1099 | # The following do not modify their arguments: | |
1100 | ||
1101 | bgcd(@values); # greatest common divisor | |
1102 | blcm(@values); # lowest common multiplicator | |
1103 | ||
1104 | $x->bstr(); # return string | |
1105 | $x->bsstr(); # return string in scientific notation | |
1106 | ||
1107 | $x->exponent(); # return exponent as BigInt | |
1108 | $x->mantissa(); # return mantissa as BigInt | |
1109 | $x->parts(); # return (mantissa,exponent) as BigInt | |
1110 | ||
1111 | $x->length(); # number of digits (w/o sign and '.') | |
1112 | ($l,$f) = $x->length(); # number of digits, and length of fraction | |
a5f75d66 AD |
1113 | |
1114 | =head1 DESCRIPTION | |
1115 | ||
58cde26e JH |
1116 | All operators (inlcuding basic math operations) are overloaded if you |
1117 | declare your big floating point numbers as | |
a5f75d66 | 1118 | |
58cde26e JH |
1119 | $i = new Math::BigFloat '12_3.456_789_123_456_789E-2'; |
1120 | ||
1121 | Operations with overloaded operators preserve the arguments, which is | |
1122 | exactly what you expect. | |
1123 | ||
1124 | =head2 Canonical notation | |
1125 | ||
1126 | Input to these routines are either BigFloat objects, or strings of the | |
1127 | following four forms: | |
a5f75d66 AD |
1128 | |
1129 | =over 2 | |
1130 | ||
58cde26e JH |
1131 | =item * |
1132 | ||
1133 | C</^[+-]\d+$/> | |
a5f75d66 | 1134 | |
58cde26e | 1135 | =item * |
a5f75d66 | 1136 | |
58cde26e | 1137 | C</^[+-]\d+\.\d*$/> |
a5f75d66 | 1138 | |
58cde26e | 1139 | =item * |
a5f75d66 | 1140 | |
58cde26e | 1141 | C</^[+-]\d+E[+-]?\d+$/> |
a5f75d66 | 1142 | |
58cde26e | 1143 | =item * |
a5f75d66 | 1144 | |
58cde26e | 1145 | C</^[+-]\d*\.\d+E[+-]?\d+$/> |
5d7098d5 | 1146 | |
58cde26e JH |
1147 | =back |
1148 | ||
1149 | all with optional leading and trailing zeros and/or spaces. Additonally, | |
1150 | numbers are allowed to have an underscore between any two digits. | |
1151 | ||
1152 | Empty strings as well as other illegal numbers results in 'NaN'. | |
1153 | ||
1154 | bnorm() on a BigFloat object is now effectively a no-op, since the numbers | |
1155 | are always stored in normalized form. On a string, it creates a BigFloat | |
1156 | object. | |
1157 | ||
1158 | =head2 Output | |
1159 | ||
1160 | Output values are BigFloat objects (normalized), except for bstr() and bsstr(). | |
1161 | ||
1162 | The string output will always have leading and trailing zeros stripped and drop | |
1163 | a plus sign. C<bstr()> will give you always the form with a decimal point, | |
1164 | while C<bsstr()> (for scientific) gives you the scientific notation. | |
1165 | ||
1166 | Input bstr() bsstr() | |
1167 | '-0' '0' '0E1' | |
1168 | ' -123 123 123' '-123123123' '-123123123E0' | |
1169 | '00.0123' '0.0123' '123E-4' | |
1170 | '123.45E-2' '1.2345' '12345E-4' | |
1171 | '10E+3' '10000' '1E4' | |
1172 | ||
1173 | Some routines (C<is_odd()>, C<is_even()>, C<is_zero()>, C<is_one()>, | |
1174 | C<is_nan()>) return true or false, while others (C<bcmp()>, C<bacmp()>) | |
1175 | return either undef, <0, 0 or >0 and are suited for sort. | |
1176 | ||
1177 | Actual math is done by using BigInts to represent the mantissa and exponent. | |
1178 | The sign C</^[+-]$/> is stored separately. The string 'NaN' is used to | |
1179 | represent the result when input arguments are not numbers, as well as | |
1180 | the result of dividing by zero. | |
1181 | ||
1182 | =head2 C<mantissa()>, C<exponent()> and C<parts()> | |
1183 | ||
1184 | C<mantissa()> and C<exponent()> return the said parts of the BigFloat | |
1185 | as BigInts such that: | |
1186 | ||
1187 | $m = $x->mantissa(); | |
1188 | $e = $x->exponent(); | |
1189 | $y = $m * ( 10 ** $e ); | |
1190 | print "ok\n" if $x == $y; | |
1191 | ||
1192 | C<< ($m,$e) = $x->parts(); >> is just a shortcut giving you both of them. | |
1193 | ||
1194 | A zero is represented and returned as C<0E1>, B<not> C<0E0> (after Knuth). | |
1195 | ||
1196 | Currently the mantissa is reduced as much as possible, favouring higher | |
1197 | exponents over lower ones (e.g. returning 1e7 instead of 10e6 or 10000000e0). | |
1198 | This might change in the future, so do not depend on it. | |
1199 | ||
1200 | =head2 Accuracy vs. Precision | |
1201 | ||
1202 | See also: L<Rounding|Rounding>. | |
1203 | ||
1204 | Math::BigFloat supports both precision and accuracy. (here should follow | |
1205 | a short description of both). | |
5d7098d5 | 1206 | |
58cde26e JH |
1207 | Precision: digits after the '.', laber, schwad |
1208 | Accuracy: Significant digits blah blah | |
5d7098d5 | 1209 | |
58cde26e JH |
1210 | Since things like sqrt(2) or 1/3 must presented with a limited precision lest |
1211 | a operation consumes all resources, each operation produces no more than | |
1212 | C<Math::BigFloat::precision()> digits. | |
1213 | ||
1214 | In case the result of one operation has more precision than specified, | |
1215 | it is rounded. The rounding mode taken is either the default mode, or the one | |
1216 | supplied to the operation after the I<scale>: | |
1217 | ||
1218 | $x = Math::BigFloat->new(2); | |
1219 | Math::BigFloat::precision(5); # 5 digits max | |
1220 | $y = $x->copy()->bdiv(3); # will give 0.66666 | |
1221 | $y = $x->copy()->bdiv(3,6); # will give 0.666666 | |
1222 | $y = $x->copy()->bdiv(3,6,'odd'); # will give 0.666667 | |
1223 | Math::BigFloat::round_mode('zero'); | |
1224 | $y = $x->copy()->bdiv(3,6); # will give 0.666666 | |
1225 | ||
1226 | =head2 Rounding | |
1227 | ||
1228 | =over 2 | |
1229 | ||
5dc6f178 | 1230 | =item ffround ( +$scale ) |
58cde26e | 1231 | |
5dc6f178 JH |
1232 | rounds to the $scale'th place left from the '.', counting from the dot. |
1233 | The first digit is numbered 1. | |
58cde26e | 1234 | |
5dc6f178 | 1235 | =item ffround ( -$scale ) |
58cde26e | 1236 | |
5dc6f178 | 1237 | rounds to the $scale'th place right from the '.', counting from the dot |
58cde26e | 1238 | |
5dc6f178 JH |
1239 | =item ffround ( 0 ) |
1240 | ||
1241 | rounds to an integer | |
1242 | ||
1243 | =item fround ( +$scale ) | |
1244 | ||
1245 | preserves accuracy to $scale digits from the left (aka significant | |
1246 | digits) and pads the rest with zeros. If the number is between 1 and | |
1247 | -1, the significant digits count from the first non-zero after the '.' | |
1248 | ||
1249 | =item fround ( -$scale ) and fround ( 0 ) | |
1250 | ||
1251 | are a no-ops | |
5d7098d5 | 1252 | |
a5f75d66 AD |
1253 | =back |
1254 | ||
5dc6f178 JH |
1255 | All rounding functions take as a second parameter a rounding mode from |
1256 | one of the following: 'even', 'odd', '+inf', '-inf', 'zero' or 'trunc'. | |
58cde26e JH |
1257 | |
1258 | The default rounding mode is 'even'. By using | |
5dc6f178 JH |
1259 | C<< Math::BigFloat::round_mode($rnd_mode); >> you can get and set the |
1260 | default mode for subsequent rounding. The usage of | |
1261 | C<$Math::BigFloat::$rnd_mode> is no longer supported. | |
1262 | The second parameter to the round functions then overrides the default | |
1263 | temporarily. | |
58cde26e JH |
1264 | |
1265 | The C<< as_number() >> function returns a BigInt from a Math::BigFloat. It uses | |
1266 | 'trunc' as rounding mode to make it equivalent to: | |
1267 | ||
1268 | $x = 2.5; | |
1269 | $y = int($x) + 2; | |
1270 | ||
1271 | You can override this by passing the desired rounding mode as parameter to | |
1272 | C<as_number()>: | |
1273 | ||
1274 | $x = Math::BigFloat->new(2.5); | |
1275 | $y = $x->as_number('odd'); # $y = 3 | |
1276 | ||
1277 | =head1 EXAMPLES | |
1278 | ||
1279 | use Math::BigFloat qw(bstr bint); | |
1280 | # not ready yet | |
1281 | $x = bstr("1234") # string "1234" | |
1282 | $x = "$x"; # same as bstr() | |
1283 | $x = bneg("1234") # BigFloat "-1234" | |
1284 | $x = Math::BigFloat->bneg("1234"); # BigFloat "1234" | |
1285 | $x = Math::BigFloat->babs("-12345"); # BigFloat "12345" | |
1286 | $x = Math::BigFloat->bnorm("-0 00"); # BigFloat "0" | |
1287 | $x = bint(1) + bint(2); # BigFloat "3" | |
1288 | $x = bint(1) + "2"; # ditto (auto-BigFloatify of "2") | |
1289 | $x = bint(1); # BigFloat "1" | |
1290 | $x = $x + 5 / 2; # BigFloat "3" | |
1291 | $x = $x ** 3; # BigFloat "27" | |
1292 | $x *= 2; # BigFloat "54" | |
1293 | $x = new Math::BigFloat; # BigFloat "0" | |
1294 | $x--; # BigFloat "-1" | |
1295 | ||
1296 | =head1 Autocreating constants | |
1297 | ||
1298 | After C<use Math::BigFloat ':constant'> all the floating point constants | |
1299 | in the given scope are converted to C<Math::BigFloat>. This conversion | |
1300 | happens at compile time. | |
1301 | ||
1302 | In particular | |
1303 | ||
1304 | perl -MMath::BigFloat=:constant -e 'print 2E-100,"\n"' | |
1305 | ||
1306 | prints the value of C<2E-100>. Note that without conversion of | |
1307 | constants the expression 2E-100 will be calculated as normal floating point | |
1308 | number. | |
1309 | ||
1310 | =head1 PERFORMANCE | |
1311 | ||
1312 | Greatly enhanced ;o) | |
1313 | SectionNotReadyYet. | |
1314 | ||
a5f75d66 AD |
1315 | =head1 BUGS |
1316 | ||
58cde26e JH |
1317 | =over 2 |
1318 | ||
1319 | =item * | |
1320 | ||
1321 | The following does not work yet: | |
1322 | ||
1323 | $m = $x->mantissa(); | |
1324 | $e = $x->exponent(); | |
1325 | $y = $m * ( 10 ** $e ); | |
1326 | print "ok\n" if $x == $y; | |
1327 | ||
1328 | =item * | |
1329 | ||
1330 | There is no fmod() function yet. | |
1331 | ||
1332 | =back | |
1333 | ||
1334 | =head1 CAVEAT | |
1335 | ||
1336 | =over 1 | |
1337 | ||
1338 | =item stringify, bstr() | |
1339 | ||
1340 | Both stringify and bstr() now drop the leading '+'. The old code would return | |
1341 | '+1.23', the new returns '1.23'. See the documentation in L<Math::BigInt> for | |
1342 | reasoning and details. | |
1343 | ||
1344 | =item bdiv | |
1345 | ||
1346 | The following will probably not do what you expect: | |
1347 | ||
1348 | print $c->bdiv(123.456),"\n"; | |
1349 | ||
1350 | It prints both quotient and reminder since print works in list context. Also, | |
1351 | bdiv() will modify $c, so be carefull. You probably want to use | |
1352 | ||
1353 | print $c / 123.456,"\n"; | |
1354 | print scalar $c->bdiv(123.456),"\n"; # or if you want to modify $c | |
1355 | ||
1356 | instead. | |
1357 | ||
1358 | =item Modifying and = | |
1359 | ||
1360 | Beware of: | |
1361 | ||
1362 | $x = Math::BigFloat->new(5); | |
1363 | $y = $x; | |
1364 | ||
1365 | It will not do what you think, e.g. making a copy of $x. Instead it just makes | |
1366 | a second reference to the B<same> object and stores it in $y. Thus anything | |
1367 | that modifies $x will modify $y, and vice versa. | |
1368 | ||
1369 | $x->bmul(2); | |
1370 | print "$x, $y\n"; # prints '10, 10' | |
1371 | ||
1372 | If you want a true copy of $x, use: | |
1373 | ||
1374 | $y = $x->copy(); | |
1375 | ||
1376 | See also the documentation in L<overload> regarding C<=>. | |
1377 | ||
1378 | =item bpow | |
1379 | ||
1380 | C<bpow()> now modifies the first argument, unlike the old code which left | |
1381 | it alone and only returned the result. This is to be consistent with | |
1382 | C<badd()> etc. The first will modify $x, the second one won't: | |
1383 | ||
1384 | print bpow($x,$i),"\n"; # modify $x | |
1385 | print $x->bpow($i),"\n"; # ditto | |
1386 | print $x ** $i,"\n"; # leave $x alone | |
1387 | ||
1388 | =back | |
1389 | ||
1390 | =head1 LICENSE | |
a5f75d66 | 1391 | |
58cde26e JH |
1392 | This program is free software; you may redistribute it and/or modify it under |
1393 | the same terms as Perl itself. | |
5d7098d5 | 1394 | |
58cde26e | 1395 | =head1 AUTHORS |
5d7098d5 | 1396 | |
58cde26e JH |
1397 | Mark Biggar, overloaded interface by Ilya Zakharevich. |
1398 | Completely rewritten by Tels http://bloodgate.com in 2001. | |
a5f75d66 | 1399 | |
a5f75d66 | 1400 | =cut |