Commit | Line | Data |
---|---|---|
126f3c5f | 1 | package bignum; |
95a2d02c | 2 | use 5.006002; |
126f3c5f | 3 | |
4440d13a | 4 | $VERSION = '0.22'; |
126f3c5f | 5 | use Exporter; |
d1a15766 | 6 | @ISA = qw( bigint ); |
d98d5fa0 | 7 | @EXPORT_OK = qw( PI e bexp bpi ); |
b4bc5691 | 8 | @EXPORT = qw( inf NaN ); |
126f3c5f JH |
9 | |
10 | use strict; | |
95a2d02c | 11 | use overload; |
d1a15766 | 12 | require bigint; # no "use" to avoid import being called |
126f3c5f JH |
13 | |
14 | ############################################################################## | |
15 | ||
d1a15766 T |
16 | BEGIN |
17 | { | |
18 | *inf = \&bigint::inf; | |
19 | *NaN = \&bigint::NaN; | |
20 | } | |
21 | ||
126f3c5f JH |
22 | # These are all alike, and thus faked by AUTOLOAD |
23 | ||
24 | my @faked = qw/round_mode accuracy precision div_scale/; | |
25 | use vars qw/$VERSION $AUTOLOAD $_lite/; # _lite for testsuite | |
26 | ||
27 | sub AUTOLOAD | |
28 | { | |
29 | my $name = $AUTOLOAD; | |
30 | ||
31 | $name =~ s/.*:://; # split package | |
32 | no strict 'refs'; | |
33 | foreach my $n (@faked) | |
34 | { | |
35 | if ($n eq $name) | |
36 | { | |
37 | *{"bignum::$name"} = sub | |
38 | { | |
39 | my $self = shift; | |
40 | no strict 'refs'; | |
41 | if (defined $_[0]) | |
42 | { | |
43 | Math::BigInt->$name($_[0]); | |
990fb837 | 44 | return Math::BigFloat->$name($_[0]); |
126f3c5f JH |
45 | } |
46 | return Math::BigInt->$name(); | |
47 | }; | |
48 | return &$name; | |
49 | } | |
50 | } | |
51 | ||
52 | # delayed load of Carp and avoid recursion | |
53 | require Carp; | |
54 | Carp::croak ("Can't call bignum\-\>$name, not a valid method"); | |
55 | } | |
56 | ||
4440d13a T |
57 | sub unimport |
58 | { | |
59 | $^H{bignum} = undef; # no longer in effect | |
60 | overload::remove_constant('binary','','float','','integer'); | |
61 | } | |
62 | ||
63 | sub in_effect | |
64 | { | |
65 | my $level = shift || 0; | |
66 | my $hinthash = (caller($level))[10]; | |
67 | $hinthash->{bignum}; | |
68 | } | |
69 | ||
d1a15766 T |
70 | ############################################################################# |
71 | # the following two routines are for Perl 5.9.4 or later and are lexical | |
72 | ||
73 | sub _hex | |
74 | { | |
75 | return CORE::hex($_[0]) unless in_effect(1); | |
76 | my $i = $_[0]; | |
77 | $i = '0x'.$i unless $i =~ /^0x/; | |
78 | Math::BigInt->new($i); | |
79 | } | |
80 | ||
81 | sub _oct | |
82 | { | |
83 | return CORE::oct($_[0]) unless in_effect(1); | |
84 | my $i = $_[0]; | |
85 | return Math::BigInt->from_oct($i) if $i =~ /^0[0-7]/; | |
86 | Math::BigInt->new($i); | |
87 | } | |
88 | ||
126f3c5f JH |
89 | sub import |
90 | { | |
91 | my $self = shift; | |
92 | ||
4440d13a T |
93 | $^H{bignum} = 1; # we are in effect |
94 | ||
075d4edd RGS |
95 | my ($hex,$oct); |
96 | ||
d1a15766 T |
97 | # for newer Perls override hex() and oct() with a lexical version: |
98 | if ($] > 5.009003) | |
99 | { | |
075d4edd RGS |
100 | $hex = \&_hex; |
101 | $oct = \&_oct; | |
d1a15766 T |
102 | } |
103 | ||
126f3c5f | 104 | # some defaults |
bd49aa09 | 105 | my $lib = ''; my $lib_kind = 'try'; |
126f3c5f JH |
106 | my $upgrade = 'Math::BigFloat'; |
107 | my $downgrade = 'Math::BigInt'; | |
108 | ||
109 | my @import = ( ':constant' ); # drive it w/ constant | |
110 | my @a = @_; my $l = scalar @_; my $j = 0; | |
111 | my ($ver,$trace); # version? trace? | |
112 | my ($a,$p); # accuracy, precision | |
113 | for ( my $i = 0; $i < $l ; $i++,$j++ ) | |
114 | { | |
115 | if ($_[$i] eq 'upgrade') | |
116 | { | |
117 | # this causes upgrading | |
118 | $upgrade = $_[$i+1]; # or undef to disable | |
119 | my $s = 2; $s = 1 if @a-$j < 2; # avoid "can not modify non-existant..." | |
120 | splice @a, $j, $s; $j -= $s; $i++; | |
121 | } | |
122 | elsif ($_[$i] eq 'downgrade') | |
123 | { | |
124 | # this causes downgrading | |
125 | $downgrade = $_[$i+1]; # or undef to disable | |
126 | my $s = 2; $s = 1 if @a-$j < 2; # avoid "can not modify non-existant..." | |
127 | splice @a, $j, $s; $j -= $s; $i++; | |
128 | } | |
bd49aa09 | 129 | elsif ($_[$i] =~ /^(l|lib|try|only)$/) |
126f3c5f JH |
130 | { |
131 | # this causes a different low lib to take care... | |
bd49aa09 | 132 | $lib_kind = $1; $lib_kind = 'lib' if $lib_kind eq 'l'; |
126f3c5f JH |
133 | $lib = $_[$i+1] || ''; |
134 | my $s = 2; $s = 1 if @a-$j < 2; # avoid "can not modify non-existant..." | |
135 | splice @a, $j, $s; $j -= $s; $i++; | |
136 | } | |
137 | elsif ($_[$i] =~ /^(a|accuracy)$/) | |
138 | { | |
139 | $a = $_[$i+1]; | |
140 | my $s = 2; $s = 1 if @a-$j < 2; # avoid "can not modify non-existant..." | |
141 | splice @a, $j, $s; $j -= $s; $i++; | |
142 | } | |
143 | elsif ($_[$i] =~ /^(p|precision)$/) | |
144 | { | |
145 | $p = $_[$i+1]; | |
146 | my $s = 2; $s = 1 if @a-$j < 2; # avoid "can not modify non-existant..." | |
147 | splice @a, $j, $s; $j -= $s; $i++; | |
148 | } | |
149 | elsif ($_[$i] =~ /^(v|version)$/) | |
150 | { | |
151 | $ver = 1; | |
152 | splice @a, $j, 1; $j --; | |
153 | } | |
154 | elsif ($_[$i] =~ /^(t|trace)$/) | |
155 | { | |
156 | $trace = 1; | |
157 | splice @a, $j, 1; $j --; | |
158 | } | |
d1a15766 T |
159 | elsif ($_[$i] eq 'hex') |
160 | { | |
161 | splice @a, $j, 1; $j --; | |
075d4edd | 162 | $hex = \&bigint::_hex_global; |
d1a15766 T |
163 | } |
164 | elsif ($_[$i] eq 'oct') | |
165 | { | |
166 | splice @a, $j, 1; $j --; | |
075d4edd | 167 | $oct = \&bigint::_oct_global; |
d1a15766 | 168 | } |
d98d5fa0 | 169 | elsif ($_[$i] !~ /^(PI|e|bexp|bpi)\z/) |
fade31f0 T |
170 | { |
171 | die ("unknown option $_[$i]"); | |
172 | } | |
126f3c5f JH |
173 | } |
174 | my $class; | |
175 | $_lite = 0; # using M::BI::L ? | |
176 | if ($trace) | |
177 | { | |
178 | require Math::BigInt::Trace; $class = 'Math::BigInt::Trace'; | |
179 | $upgrade = 'Math::BigFloat::Trace'; | |
126f3c5f JH |
180 | } |
181 | else | |
182 | { | |
183 | # see if we can find Math::BigInt::Lite | |
184 | if (!defined $a && !defined $p) # rounding won't work to well | |
185 | { | |
186 | eval 'require Math::BigInt::Lite;'; | |
187 | if ($@ eq '') | |
188 | { | |
189 | @import = ( ); # :constant in Lite, not MBI | |
190 | Math::BigInt::Lite->import( ':constant' ); | |
191 | $_lite= 1; # signal okay | |
192 | } | |
193 | } | |
194 | require Math::BigInt if $_lite == 0; # not already loaded? | |
195 | $class = 'Math::BigInt'; # regardless of MBIL or not | |
233f7bc0 | 196 | } |
48441d71 | 197 | push @import, $lib_kind => $lib if $lib ne ''; |
126f3c5f | 198 | # Math::BigInt::Trace or plain Math::BigInt |
233f7bc0 | 199 | $class->import(@import, upgrade => $upgrade); |
126f3c5f JH |
200 | |
201 | if ($trace) | |
202 | { | |
203 | require Math::BigFloat::Trace; $class = 'Math::BigFloat::Trace'; | |
204 | $downgrade = 'Math::BigInt::Trace'; | |
126f3c5f JH |
205 | } |
206 | else | |
207 | { | |
208 | require Math::BigFloat; $class = 'Math::BigFloat'; | |
209 | } | |
210 | $class->import(':constant','downgrade',$downgrade); | |
211 | ||
212 | bignum->accuracy($a) if defined $a; | |
213 | bignum->precision($p) if defined $p; | |
214 | if ($ver) | |
215 | { | |
216 | print "bignum\t\t\t v$VERSION\n"; | |
217 | print "Math::BigInt::Lite\t v$Math::BigInt::Lite::VERSION\n" if $_lite; | |
218 | print "Math::BigInt\t\t v$Math::BigInt::VERSION"; | |
219 | my $config = Math::BigInt->config(); | |
220 | print " lib => $config->{lib} v$config->{lib_version}\n"; | |
221 | print "Math::BigFloat\t\t v$Math::BigFloat::VERSION\n"; | |
222 | exit; | |
223 | } | |
95a2d02c T |
224 | |
225 | # Take care of octal/hexadecimal constants | |
d1a15766 | 226 | overload::constant binary => sub { bigint::_binary_constant(shift) }; |
95a2d02c | 227 | |
4440d13a T |
228 | # if another big* was already loaded: |
229 | my ($package) = caller(); | |
230 | ||
231 | no strict 'refs'; | |
232 | if (!defined *{"${package}::inf"}) | |
233 | { | |
234 | $self->export_to_level(1,$self,@a); # export inf and NaN | |
235 | } | |
075d4edd RGS |
236 | { |
237 | no warnings 'redefine'; | |
238 | *CORE::GLOBAL::oct = $oct if $oct; | |
239 | *CORE::GLOBAL::hex = $hex if $hex; | |
240 | } | |
126f3c5f JH |
241 | } |
242 | ||
d98d5fa0 T |
243 | sub PI () { Math::BigFloat->new('3.141592653589793238462643383279502884197'); } |
244 | sub e () { Math::BigFloat->new('2.718281828459045235360287471352662497757'); } | |
245 | sub bpi ($) { Math::BigFloat::bpi(@_); } | |
246 | sub bexp ($$) { my $x = Math::BigFloat->new($_[0]); $x->bexp($_[1]); } | |
fade31f0 | 247 | |
126f3c5f JH |
248 | 1; |
249 | ||
250 | __END__ | |
251 | ||
252 | =head1 NAME | |
253 | ||
254 | bignum - Transparent BigNumber support for Perl | |
255 | ||
256 | =head1 SYNOPSIS | |
257 | ||
258 | use bignum; | |
259 | ||
260 | $x = 2 + 4.5,"\n"; # BigFloat 6.5 | |
b4bc5691 T |
261 | print 2 ** 512 * 0.1,"\n"; # really is what you think it is |
262 | print inf * inf,"\n"; # prints inf | |
263 | print NaN * 3,"\n"; # prints NaN | |
126f3c5f | 264 | |
4440d13a T |
265 | { |
266 | no bignum; | |
267 | print 2 ** 256,"\n"; # a normal Perl scalar now | |
268 | } | |
269 | ||
d1a15766 T |
270 | # for older Perls, note that this will be global: |
271 | use bignum qw/hex oct/; | |
272 | print hex("0x1234567890123490"),"\n"; | |
273 | print oct("01234567890123490"),"\n"; | |
274 | ||
126f3c5f JH |
275 | =head1 DESCRIPTION |
276 | ||
277 | All operators (including basic math operations) are overloaded. Integer and | |
278 | floating-point constants are created as proper BigInts or BigFloats, | |
279 | respectively. | |
280 | ||
24716a00 HS |
281 | If you do |
282 | ||
283 | use bignum; | |
284 | ||
285 | at the top of your script, Math::BigFloat and Math::BigInt will be loaded | |
286 | and any constant number will be converted to an object (Math::BigFloat for | |
287 | floats like 3.1415 and Math::BigInt for integers like 1234). | |
288 | ||
289 | So, the following line: | |
290 | ||
291 | $x = 1234; | |
292 | ||
293 | creates actually a Math::BigInt and stores a reference to in $x. | |
294 | This happens transparently and behind your back, so to speak. | |
295 | ||
296 | You can see this with the following: | |
297 | ||
298 | perl -Mbignum -le 'print ref(1234)' | |
299 | ||
300 | Don't worry if it says Math::BigInt::Lite, bignum and friends will use Lite | |
301 | if it is installed since it is faster for some operations. It will be | |
3c4b39be | 302 | automatically upgraded to BigInt whenever necessary: |
24716a00 HS |
303 | |
304 | perl -Mbignum -le 'print ref(2**255)' | |
305 | ||
306 | This also means it is a bad idea to check for some specific package, since | |
307 | the actual contents of $x might be something unexpected. Due to the | |
3c4b39be | 308 | transparent way of bignum C<ref()> should not be necessary, anyway. |
24716a00 HS |
309 | |
310 | Since Math::BigInt and BigFloat also overload the normal math operations, | |
311 | the following line will still work: | |
312 | ||
313 | perl -Mbignum -le 'print ref(1234+1234)' | |
314 | ||
315 | Since numbers are actually objects, you can call all the usual methods from | |
316 | BigInt/BigFloat on them. This even works to some extent on expressions: | |
317 | ||
318 | perl -Mbignum -le '$x = 1234; print $x->bdec()' | |
d1a15766 T |
319 | perl -Mbignum -le 'print 1234->copy()->binc();' |
320 | perl -Mbignum -le 'print 1234->copy()->binc->badd(6);' | |
321 | perl -Mbignum -le 'print +(1234)->copy()->binc()' | |
24716a00 HS |
322 | |
323 | (Note that print doesn't do what you expect if the expression starts with | |
324 | '(' hence the C<+>) | |
325 | ||
326 | You can even chain the operations together as usual: | |
327 | ||
d1a15766 | 328 | perl -Mbignum -le 'print 1234->copy()->binc->badd(6);' |
24716a00 HS |
329 | 1241 |
330 | ||
331 | Under bignum (or bigint or bigrat), Perl will "upgrade" the numbers | |
332 | appropriately. This means that: | |
333 | ||
334 | perl -Mbignum -le 'print 1234+4.5' | |
335 | 1238.5 | |
336 | ||
337 | will work correctly. These mixed cases don't do always work when using | |
338 | Math::BigInt or Math::BigFloat alone, or at least not in the way normal Perl | |
339 | scalars work. | |
340 | ||
341 | If you do want to work with large integers like under C<use integer;>, try | |
342 | C<use bigint;>: | |
343 | ||
344 | perl -Mbigint -le 'print 1234.5+4.5' | |
345 | 1238 | |
346 | ||
347 | There is also C<use bigrat;> which gives you big rationals: | |
348 | ||
349 | perl -Mbigrat -le 'print 1234+4.1' | |
350 | 12381/10 | |
351 | ||
352 | The entire upgrading/downgrading is still experimental and might not work | |
d1a15766 | 353 | as you expect or may even have bugs. You might get errors like this: |
24716a00 HS |
354 | |
355 | Can't use an undefined value as an ARRAY reference at | |
356 | /usr/local/lib/perl5/5.8.0/Math/BigInt/Calc.pm line 864 | |
357 | ||
358 | This means somewhere a routine got a BigFloat/Lite but expected a BigInt (or | |
359 | vice versa) and the upgrade/downgrad path was missing. This is a bug, please | |
360 | report it so that we can fix it. | |
361 | ||
362 | You might consider using just Math::BigInt or Math::BigFloat, since they | |
363 | allow you finer control over what get's done in which module/space. For | |
364 | instance, simple loop counters will be Math::BigInts under C<use bignum;> and | |
365 | this is slower than keeping them as Perl scalars: | |
366 | ||
367 | perl -Mbignum -le 'for ($i = 0; $i < 10; $i++) { print ref($i); }' | |
368 | ||
369 | Please note the following does not work as expected (prints nothing), since | |
370 | overloading of '..' is not yet possible in Perl (as of v5.8.0): | |
371 | ||
372 | perl -Mbignum -le 'for (1..2) { print ref($_); }' | |
373 | ||
b68b7ab1 | 374 | =head2 Options |
126f3c5f JH |
375 | |
376 | bignum recognizes some options that can be passed while loading it via use. | |
377 | The options can (currently) be either a single letter form, or the long form. | |
378 | The following options exist: | |
379 | ||
380 | =over 2 | |
381 | ||
382 | =item a or accuracy | |
383 | ||
384 | This sets the accuracy for all math operations. The argument must be greater | |
385 | than or equal to zero. See Math::BigInt's bround() function for details. | |
386 | ||
387 | perl -Mbignum=a,50 -le 'print sqrt(20)' | |
388 | ||
95a2d02c T |
389 | Note that setting precision and accurary at the same time is not possible. |
390 | ||
126f3c5f JH |
391 | =item p or precision |
392 | ||
393 | This sets the precision for all math operations. The argument can be any | |
394 | integer. Negative values mean a fixed number of digits after the dot, while | |
395 | a positive value rounds to this digit left from the dot. 0 or 1 mean round to | |
396 | integer. See Math::BigInt's bfround() function for details. | |
397 | ||
398 | perl -Mbignum=p,-50 -le 'print sqrt(20)' | |
399 | ||
95a2d02c T |
400 | Note that setting precision and accurary at the same time is not possible. |
401 | ||
126f3c5f JH |
402 | =item t or trace |
403 | ||
404 | This enables a trace mode and is primarily for debugging bignum or | |
405 | Math::BigInt/Math::BigFloat. | |
406 | ||
407 | =item l or lib | |
408 | ||
409 | Load a different math lib, see L<MATH LIBRARY>. | |
410 | ||
411 | perl -Mbignum=l,GMP -e 'print 2 ** 512' | |
412 | ||
413 | Currently there is no way to specify more than one library on the command | |
95a2d02c T |
414 | line. This means the following does not work: |
415 | ||
416 | perl -Mbignum=l,GMP,Pari -e 'print 2 ** 512' | |
417 | ||
418 | This will be hopefully fixed soon ;) | |
126f3c5f | 419 | |
d1a15766 T |
420 | =item hex |
421 | ||
43cde5e1 | 422 | Override the built-in hex() method with a version that can handle big |
d1a15766 T |
423 | integers. Note that under Perl older than v5.9.4, this will be global |
424 | and cannot be disabled with "no bigint;". | |
425 | ||
426 | =item oct | |
427 | ||
43cde5e1 | 428 | Override the built-in oct() method with a version that can handle big |
d1a15766 T |
429 | integers. Note that under Perl older than v5.9.4, this will be global |
430 | and cannot be disabled with "no bigint;". | |
431 | ||
126f3c5f JH |
432 | =item v or version |
433 | ||
434 | This prints out the name and version of all modules used and then exits. | |
435 | ||
b68b7ab1 | 436 | perl -Mbignum=v |
126f3c5f | 437 | |
95a2d02c T |
438 | =back |
439 | ||
b68b7ab1 | 440 | =head2 Methods |
b4bc5691 T |
441 | |
442 | Beside import() and AUTOLOAD() there are only a few other methods. | |
443 | ||
24716a00 HS |
444 | Since all numbers are now objects, you can use all functions that are part of |
445 | the BigInt or BigFloat API. It is wise to use only the bxxx() notation, and not | |
446 | the fxxx() notation, though. This makes it possible that the underlying object | |
447 | might morph into a different class than BigFloat. | |
448 | ||
4440d13a | 449 | =head2 Caveats |
990fb837 RGS |
450 | |
451 | But a warning is in order. When using the following to make a copy of a number, | |
452 | only a shallow copy will be made. | |
453 | ||
454 | $x = 9; $y = $x; | |
455 | $x = $y = 7; | |
456 | ||
b68b7ab1 T |
457 | If you want to make a real copy, use the following: |
458 | ||
459 | $y = $x->copy(); | |
460 | ||
990fb837 RGS |
461 | Using the copy or the original with overloaded math is okay, e.g. the |
462 | following work: | |
463 | ||
464 | $x = 9; $y = $x; | |
465 | print $x + 1, " ", $y,"\n"; # prints 10 9 | |
466 | ||
467 | but calling any method that modifies the number directly will result in | |
3c4b39be | 468 | B<both> the original and the copy being destroyed: |
990fb837 RGS |
469 | |
470 | $x = 9; $y = $x; | |
471 | print $x->badd(1), " ", $y,"\n"; # prints 10 10 | |
472 | ||
473 | $x = 9; $y = $x; | |
474 | print $x->binc(1), " ", $y,"\n"; # prints 10 10 | |
475 | ||
476 | $x = 9; $y = $x; | |
477 | print $x->bmul(2), " ", $y,"\n"; # prints 18 18 | |
478 | ||
d1a15766 | 479 | Using methods that do not modify, but test the contents works: |
990fb837 RGS |
480 | |
481 | $x = 9; $y = $x; | |
482 | $z = 9 if $x->is_zero(); # works fine | |
483 | ||
484 | See the documentation about the copy constructor and C<=> in overload, as | |
485 | well as the documentation in BigInt for further details. | |
486 | ||
b4bc5691 T |
487 | =over 2 |
488 | ||
489 | =item inf() | |
490 | ||
3c4b39be | 491 | A shortcut to return Math::BigInt->binf(). Useful because Perl does not always |
b4bc5691 T |
492 | handle bareword C<inf> properly. |
493 | ||
494 | =item NaN() | |
495 | ||
3c4b39be | 496 | A shortcut to return Math::BigInt->bnan(). Useful because Perl does not always |
b4bc5691 T |
497 | handle bareword C<NaN> properly. |
498 | ||
d98d5fa0 | 499 | =item e |
fade31f0 | 500 | |
d98d5fa0 T |
501 | # perl -Mbignum=e -wle 'print e' |
502 | ||
503 | Returns Euler's number C<e>, aka exp(1). | |
fade31f0 T |
504 | |
505 | =item PI() | |
506 | ||
d98d5fa0 T |
507 | # perl -Mbignum=PI -wle 'print PI' |
508 | ||
509 | Returns PI. | |
510 | ||
511 | =item bexp() | |
512 | ||
513 | bexp($power,$accuracy); | |
514 | ||
515 | Returns Euler's number C<e> raised to the appropriate power, to | |
516 | the wanted accuracy. | |
517 | ||
518 | Example: | |
519 | ||
520 | # perl -Mbignum=bexp -wle 'print bexp(1,80)' | |
521 | ||
522 | =item bpi() | |
523 | ||
524 | bpi($accuracy); | |
525 | ||
526 | Returns PI to the wanted accuracy. | |
527 | ||
528 | Example: | |
529 | ||
530 | # perl -Mbignum=bpi -wle 'print bpi(80)' | |
fade31f0 | 531 | |
b4bc5691 T |
532 | =item upgrade() |
533 | ||
534 | Return the class that numbers are upgraded to, is in fact returning | |
535 | C<$Math::BigInt::upgrade>. | |
536 | ||
4440d13a T |
537 | =item in_effect() |
538 | ||
539 | use bignum; | |
540 | ||
541 | print "in effect\n" if bignum::in_effect; # true | |
542 | { | |
543 | no bignum; | |
544 | print "in effect\n" if bignum::in_effect; # false | |
545 | } | |
546 | ||
547 | Returns true or false if C<bignum> is in effect in the current scope. | |
548 | ||
549 | This method only works on Perl v5.9.4 or later. | |
550 | ||
b4bc5691 T |
551 | =back |
552 | ||
bd49aa09 | 553 | =head2 Math Library |
126f3c5f JH |
554 | |
555 | Math with the numbers is done (by default) by a module called | |
556 | Math::BigInt::Calc. This is equivalent to saying: | |
557 | ||
558 | use bignum lib => 'Calc'; | |
559 | ||
560 | You can change this by using: | |
561 | ||
bd49aa09 | 562 | use bignum lib => 'GMP'; |
126f3c5f JH |
563 | |
564 | The following would first try to find Math::BigInt::Foo, then | |
565 | Math::BigInt::Bar, and when this also fails, revert to Math::BigInt::Calc: | |
566 | ||
567 | use bignum lib => 'Foo,Math::BigInt::Bar'; | |
568 | ||
569 | Please see respective module documentation for further details. | |
570 | ||
bd49aa09 SP |
571 | Using C<lib> warns if none of the specified libraries can be found and |
572 | L<Math::BigInt> did fall back to one of the default libraries. | |
573 | To supress this warning, use C<try> instead: | |
574 | ||
575 | use bignum try => 'GMP'; | |
576 | ||
577 | If you want the code to die instead of falling back, use C<only> instead: | |
578 | ||
579 | use bignum only => 'GMP'; | |
580 | ||
126f3c5f JH |
581 | =head2 INTERNAL FORMAT |
582 | ||
583 | The numbers are stored as objects, and their internals might change at anytime, | |
584 | especially between math operations. The objects also might belong to different | |
585 | classes, like Math::BigInt, or Math::BigFLoat. Mixing them together, even | |
586 | with normal scalars is not extraordinary, but normal and expected. | |
587 | ||
588 | You should not depend on the internal format, all accesses must go through | |
589 | accessor methods. E.g. looking at $x->{sign} is not a bright idea since there | |
590 | is no guaranty that the object in question has such a hashkey, nor is a hash | |
591 | underneath at all. | |
592 | ||
593 | =head2 SIGN | |
594 | ||
595 | The sign is either '+', '-', 'NaN', '+inf' or '-inf' and stored seperately. | |
596 | You can access it with the sign() method. | |
597 | ||
598 | A sign of 'NaN' is used to represent the result when input arguments are not | |
599 | numbers or as a result of 0/0. '+inf' and '-inf' represent plus respectively | |
600 | minus infinity. You will get '+inf' when dividing a positive number by 0, and | |
601 | '-inf' when dividing any negative number by 0. | |
602 | ||
d1a15766 T |
603 | =head1 CAVAETS |
604 | ||
605 | =over 2 | |
606 | ||
607 | =item in_effect() | |
608 | ||
609 | This method only works on Perl v5.9.4 or later. | |
610 | ||
611 | =item hex()/oct() | |
612 | ||
613 | C<bigint> overrides these routines with versions that can also handle | |
614 | big integer values. Under Perl prior to version v5.9.4, however, this | |
615 | will not happen unless you specifically ask for it with the two | |
616 | import tags "hex" and "oct" - and then it will be global and cannot be | |
617 | disabled inside a scope with "no bigint": | |
618 | ||
619 | use bigint qw/hex oct/; | |
620 | ||
621 | print hex("0x1234567890123456"); | |
622 | { | |
623 | no bigint; | |
624 | print hex("0x1234567890123456"); | |
625 | } | |
626 | ||
627 | The second call to hex() will warn about a non-portable constant. | |
628 | ||
629 | Compare this to: | |
630 | ||
631 | use bigint; | |
632 | ||
633 | # will warn only under older than v5.9.4 | |
634 | print hex("0x1234567890123456"); | |
635 | ||
636 | =back | |
637 | ||
126f3c5f JH |
638 | =head1 MODULES USED |
639 | ||
640 | C<bignum> is just a thin wrapper around various modules of the Math::BigInt | |
641 | family. Think of it as the head of the family, who runs the shop, and orders | |
642 | the others to do the work. | |
643 | ||
644 | The following modules are currently used by bignum: | |
645 | ||
646 | Math::BigInt::Lite (for speed, and only if it is loadable) | |
647 | Math::BigInt | |
648 | Math::BigFloat | |
649 | ||
650 | =head1 EXAMPLES | |
651 | ||
652 | Some cool command line examples to impress the Python crowd ;) | |
653 | ||
654 | perl -Mbignum -le 'print sqrt(33)' | |
655 | perl -Mbignum -le 'print 2*255' | |
656 | perl -Mbignum -le 'print 4.5+2*255' | |
657 | perl -Mbignum -le 'print 3/7 + 5/7 + 8/3' | |
658 | perl -Mbignum -le 'print 123->is_odd()' | |
659 | perl -Mbignum -le 'print log(2)' | |
bce28014 | 660 | perl -Mbignum -le 'print exp(1)' |
126f3c5f JH |
661 | perl -Mbignum -le 'print 2 ** 0.5' |
662 | perl -Mbignum=a,65 -le 'print 2 ** 0.2' | |
95a2d02c | 663 | perl -Mbignum=a,65,l,GMP -le 'print 7 ** 7777' |
126f3c5f JH |
664 | |
665 | =head1 LICENSE | |
666 | ||
667 | This program is free software; you may redistribute it and/or modify it under | |
668 | the same terms as Perl itself. | |
669 | ||
670 | =head1 SEE ALSO | |
671 | ||
672 | Especially L<bigrat> as in C<perl -Mbigrat -le 'print 1/3+1/4'>. | |
673 | ||
674 | L<Math::BigFloat>, L<Math::BigInt>, L<Math::BigRat> and L<Math::Big> as well | |
675 | as L<Math::BigInt::BitVect>, L<Math::BigInt::Pari> and L<Math::BigInt::GMP>. | |
676 | ||
677 | =head1 AUTHORS | |
678 | ||
95a2d02c | 679 | (C) by Tels L<http://bloodgate.com/> in early 2002 - 2007. |
126f3c5f JH |
680 | |
681 | =cut |