bigrat(3pm)
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::BigInt::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'.
- 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 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 independed on the fact that the underlying object might morph into a different class than BigFloat. - Cavaet
- 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;- If you want to make a real copy, use the following:
$y = $x->copy();- 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. - 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 -Mbigrat=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 -Mbigrat=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 -Mbigrat=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 -Mbigrat=v
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 - 2005.