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bigrat(3perl) Perl Programmers Reference Guide bigrat(3perl)
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' and stored seperately.
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.
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 docu-
mentation 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 v5.8.4 2001-09-21 bigrat(3perl)
Generated by $Id: phpMan.php,v 4.49 2006/02/26 13:18:18 chedong Exp $ Author: Che Dong
On Apache/2.0.61 (Unix) PHP/4.4.7 mod_ssl/2.0.61 OpenSSL/0.9.7e mod_fastcgi/2.4.2 DAV/2 SVN/1.4.2
Under GNU General Public License
2009-01-07 00:01 @38.103.63.57 Crawled by CCBot/1.0 (+http://www.commoncrawl.org/bot.html)