bignum(3)

NAME

       bignum - Transparent BigNumber support for Perl

SYNOPSIS

         use bignum;

         $x = 2 + 4.5,"\n";                    # BigFloat 6.5
         print 2 ** 512 * 0.1;                 # really is what you think it is

DESCRIPTION

       All operators (including basic math operations) are overloaded. Integer
       and floating-point constants are created as proper BigInts or
       BigFloats, respectively.

       OPTIONS

       bignum 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 -Mbignum=a,50 -le 'print sqrt(20)'

       p or precision
         This sets the precision for all math operations. The argument can be
         any integer. Negative values mean a fixed number of digits after the
         dot, while a positive value rounds to this digit left from the dot. 0
         or 1 mean round to integer. See Math::BigInt's bfround() function for
         details.

                 perl -Mbignum=p,-50 -le 'print sqrt(20)'

       t or trace
         This enables a trace mode and is primarily for debugging bignum or
         Math::BigInt/Math::BigFloat.

       l or lib
         Load a different math lib, see "MATH LIBRARY".

                 perl -Mbignum=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 -Mbignum=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 bignum lib => 'Calc';

       You can change this by using:

               use bignum lib => 'BitVect';

       The following would first try to find Math::BigInt::Foo, then
       Math::BigInt::Bar, and when this also fails, revert to Math::Big-
       Int::Calc:

               use bignum 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::BigFLoat. Mix-
       ing 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 methods. E.g. looking at $x->{sign} is not a bright
       idea since there is no guaranty that the object in question has such a
       hashkey, nor is a hash underneath at all.

       SIGN

       The sign is either '+', '-', 'NaN', '+inf' or '-inf' and stored seper-
       ately.  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 posi-
       tive 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 or BigFloat API. It is wise to use only the bxxx()
       notation, and not the fxxx() notation, though. This makes it possible
       that the underlying object might morph into a different class than
       BigFloat.

MODULES USED

       "bignum" 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 bignum:

               Math::BigInt::Lite      (for speed, and only if it is loadable)
               Math::BigInt
               Math::BigFloat

EXAMPLES

       Some cool command line examples to impress the Python crowd ;)

               perl -Mbignum -le 'print sqrt(33)'
               perl -Mbignum -le 'print 2*255'
               perl -Mbignum -le 'print 4.5+2*255'
               perl -Mbignum -le 'print 3/7 + 5/7 + 8/3'
               perl -Mbignum -le 'print 123->is_odd()'
               perl -Mbignum -le 'print log(2)'
               perl -Mbignum -le 'print 2 ** 0.5'
               perl -Mbignum=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'".

       Math::BigFloat, Math::BigInt, Math::BigRat and Math::Big as well as
       Math::BigInt::BitVect, Math::BigInt::Pari and  Math::BigInt::GMP.

AUTHORS

       (C) by Tels <http://bloodgate.com/> in early 2002.

perl v5.8.0                       2002-06-01                         bignum(3)