
bigint(3pm) Perl Programmers Reference Guide bigint(3pm)
NAME
bigint  Transparent BigInteger support for Perl
SYNOPSIS
use bignt;
$x = 2 + 4.5,"\n"; # BigInt 6
print 2 ** 512,"\n"; # really is what you think it is
print inf + 42,"\n"; # inf
print NaN * 7,"\n"; # NaN
DESCRIPTION
All operators (including basic math operations) are overloaded. Integer constants are cre
ated as proper BigInts.
Floating point constants are truncated to integer. All results are also trunctaed.
OPTIONS
bigint recognizes some options that can be passed while loading it via use. The options
can (currently) be either a single letter form, or the long form. The following options
exist:
a or accuracy
This sets the accuracy for all math operations. The argument must be greater than or
equal to zero. See Math::BigInt's bround() function for details.
perl Mbigint=a,2 le 'print 12345+1'
p or precision
This sets the precision for all math operations. The argument can be any integer. Nega
tive values mean a fixed number of digits after the dot, and are <B>ignored</B> since
all operations happen in integer space. A positive value rounds to this digit left from
the dot. 0 or 1 mean round to integer and are ignore like negative values.
See Math::BigInt's bfround() function for details.
perl Mbignum=p,5 le 'print 123456789+123'
t or trace
This enables a trace mode and is primarily for debugging bigint or Math::BigInt.
l or lib
Load a different math lib, see "MATH LIBRARY".
perl Mbigint=l,GMP e 'print 2 ** 512'
Currently there is no way to specify more than one library on the command line. This
will be hopefully fixed soon ;)
v or version
This prints out the name and version of all modules used and then exits.
perl Mbigint=v e ''
MATH LIBRARY
Math with the numbers is done (by default) by a module called Math::BigInt::Calc. This is
equivalent to saying:
use bigint lib => 'Calc';
You can change this by using:
use bigint lib => 'BitVect';
The following would first try to find Math::BigInt::Foo, then Math::BigInt::Bar, and when
this also fails, revert to Math::BigInt::Calc:
use bigint lib => 'Foo,Math::BigInt::Bar';
Please see respective module documentation for further details.
INTERNAL FORMAT
The numbers are stored as objects, and their internals might change at anytime, especially
between math operations. The objects also might belong to different classes, like
Math::BigInt, or Math::BigInt::Lite. Mixing them together, even with normal scalars is not
extraordinary, but normal and expected.
You should not depend on the internal format, all accesses must go through accessor meth
ods. E.g. looking at $x>{sign} is not a bright idea since there is no guaranty that the
object in question has such a hash key, nor is a hash underneath at all.
SIGN
The sign is either '+', '', 'NaN', '+inf' or 'inf' and stored seperately. You can
access it with the sign() method.
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.
METHODS
Since all numbers are now objects, you can use all functions that are part of the BigInt
API. You can only use the bxxx() notation, and not the fxxx() notation, though.
MODULES USED
"bigint" is just a thin wrapper around various modules of the Math::BigInt family. Think
of it as the head of the family, who runs the shop, and orders the others to do the work.
The following modules are currently used by bigint:
Math::BigInt::Lite (for speed, and only if it is loadable)
Math::BigInt
EXAMPLES
Some cool command line examples to impress the Python crowd ;) You might want to compare
them to the results under Mbignum or Mbigrat:
perl Mbigint le 'print sqrt(33)'
perl Mbigint le 'print 2*255'
perl Mbigint le 'print 4.5+2*255'
perl Mbigint le 'print 3/7 + 5/7 + 8/3'
perl Mbigint le 'print 123>is_odd()'
perl Mbigint le 'print log(2)'
perl Mbigint le 'print 2 ** 0.5'
perl Mbigint=a,65 le 'print 2 ** 0.2'
LICENSE
This program is free software; you may redistribute it and/or modify it under the same
terms as Perl itself.
SEE ALSO
Especially bigrat as in "perl Mbigrat le 'print 1/3+1/4'" and bignum as in "perl
Mbignum le 'print sqrt(2)'".
Math::BigInt, Math::BigRat and Math::Big as well as Math::BigInt::BitVect, Math::Big
Int::Pari and Math::BigInt::GMP.
AUTHORS
(C) by Tels <http://bloodgate.com/> in early 2002.
perl v5.8.0 20020601 bigint(3pm) 
