bigrat

bigrat(3)              Perl Programmers Reference Guide              bigrat(3)



NAME
       bigrat - Transparent BigNumber/BigRational support for Perl

SYNOPSIS
         use bigrat;

         $x = 2 + 4.5,"\n";                    # BigFloat 6.5
         print 1/3 + 1/4,"\n";                 # produces 7/12

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

       Other than bignum, this module upgrades to Math::BigRat, meaning that
       instead of 2.5 you will get 2+1/2 as output.

       MODULES USED

       "bigrat" 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
               Math::BigRat

       MATH LIBRARY

       Math with the numbers is done (by default) by a module called
       Math::BigInt::Calc. This is equivalent to saying:

               use bigrat lib => 'Calc';

       You can change this by using:

               use bigrat 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 bigrat lib => 'Foo,Math::BigInt::Bar';

       Please see respective module documentation for further details.

       SIGN

       The sign is either '+', '-', 'NaN', '+inf' or '-inf' and stored seper-
       ately.

       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 not 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 you inde-
       pended on the fact that the underlying object might morph into a dif-
       ferent class than BigFloat.

       CAVEAT

       But a warning is in order. When using the following to make a copy of a
       number, only a shallow copy will be made.

               $x = 9; $y = $x;
               $x = $y = 7;

       Using the copy or the original with overloaded math is okay, e.g. the
       following work:

               $x = 9; $y = $x;
               print $x + 1, " ", $y,"\n";     # prints 10 9

       but calling any method that modifies the number directly will result in
       both the original and the copy beeing destroyed:

               $x = 9; $y = $x;
               print $x->badd(1), " ", $y,"\n";        # prints 10 10

               $x = 9; $y = $x;
               print $x->binc(1), " ", $y,"\n";        # prints 10 10

               $x = 9; $y = $x;
               print $x->bmul(2), " ", $y,"\n";        # prints 18 18

       Using methods that do not modify, but testthe contents works:

               $x = 9; $y = $x;
               $z = 9 if $x->is_zero();                # works fine

       See the documentation about the copy constructor and "=" in overload,
       as well as the documentation in BigInt for further details.

EXAMPLES
               perl -Mbigrat -le 'print sqrt(33)'
               perl -Mbigrat -le 'print 2*255'
               perl -Mbigrat -le 'print 4.5+2*255'
               perl -Mbigrat -le 'print 3/7 + 5/7 + 8/3'
               perl -Mbigrat -le 'print 12->is_odd()';

LICENSE
       This program is free software; you may redistribute it and/or modify it
       under the same terms as Perl itself.

SEE ALSO
       Especially bignum.

       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 v5.8.6                       2001-09-21                         bigrat(3)