Math::BigRat(3pm) Perl Programmers Reference Guide Math::BigRat(3pm)
NAME
Math::BigRat - arbitrarily big rationales
SYNOPSIS
use Math::BigRat;
$x = Math::BigRat->new('3/7'); $x += '5/9';
print $x->bstr(),"
";
print $x ** 2,"
";
DESCRIPTION
Math::BigRat complements Math::BigInt and Math::BigFloat by providing support for arbitrarily big rationales.
MATH LIBRARY
Math with the numbers is done (by default) by a module called Math::BigInt::Calc. This is equivalent to saying:
use Math::BigRat lib => 'Calc';
You can change this by using:
use Math::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 Math::BigRat lib => 'Foo,Math::BigInt::Bar';
Calc.pm uses as internal format an array of elements of some decimal base (usually 1e7, but this might be different for some systems) with
the least significant digit first, while BitVect.pm uses a bit vector of base 2, most significant bit first. Other modules might use even
different means of representing the numbers. See the respective module documentation for further details.
Currently the following replacement libraries exist, search for them at CPAN:
Math::BigInt::BitVect
Math::BigInt::GMP
Math::BigInt::Pari
Math::BigInt::FastCalc
METHODS
Any methods not listed here are dervied from Math::BigFloat (or Math::BigInt), so make sure you check these two modules for further infor-
mation.
new()
$x = Math::BigRat->new('1/3');
Create a new Math::BigRat object. Input can come in various forms:
$x = Math::BigRat->new(123); # scalars
$x = Math::BigRat->new('123.3'); # float
$x = Math::BigRat->new('1/3'); # simple string
$x = Math::BigRat->new('1 / 3'); # spaced
$x = Math::BigRat->new('1 / 0.1'); # w/ floats
$x = Math::BigRat->new(Math::BigInt->new(3)); # BigInt
$x = Math::BigRat->new(Math::BigFloat->new('3.1')); # BigFloat
$x = Math::BigRat->new(Math::BigInt::Lite->new('2')); # BigLite
numerator()
$n = $x->numerator();
Returns a copy of the numerator (the part above the line) as signed BigInt.
denominator()
$d = $x->denominator();
Returns a copy of the denominator (the part under the line) as positive BigInt.
parts()
($n,$d) = $x->parts();
Return a list consisting of (signed) numerator and (unsigned) denominator as BigInts.
as_number()
$x = Math::BigRat->new('13/7');
print $x->as_number(),"
"; # '1'
Returns a copy of the object as BigInt by truncating it to integer.
bfac()
$x->bfac();
Calculates the factorial of $x. For instance:
print Math::BigRat->new('3/1')->bfac(),"
"; # 1*2*3
print Math::BigRat->new('5/1')->bfac(),"
"; # 1*2*3*4*5
Works currently only for integers.
blog()
Is not yet implemented.
bround()/round()/bfround()
Are not yet implemented.
is_one()
print "$x is 1
" if $x->is_one();
Return true if $x is exactly one, otherwise false.
is_zero()
print "$x is 0
" if $x->is_zero();
Return true if $x is exactly zero, otherwise false.
is_positive()
print "$x is >= 0
" if $x->is_positive();
Return true if $x is positive (greater than or equal to zero), otherwise false. Please note that '+inf' is also positive, while 'NaN' and
'-inf' aren't.
is_negative()
print "$x is < 0
" if $x->is_negative();
Return true if $x is negative (smaller than zero), otherwise false. Please note that '-inf' is also negative, while 'NaN' and '+inf'
aren't.
is_int()
print "$x is an integer
" if $x->is_int();
Return true if $x has a denominator of 1 (e.g. no fraction parts), otherwise false. Please note that '-inf', 'inf' and 'NaN' aren't inte-
ger.
is_odd()
print "$x is odd
" if $x->is_odd();
Return true if $x is odd, otherwise false.
is_even()
print "$x is even
" if $x->is_even();
Return true if $x is even, otherwise false.
bceil()
$x->bceil();
Set $x to the next bigger integer value (e.g. truncate the number to integer and then increment it by one).
bfloor()
$x->bfloor();
Truncate $x to an integer value.
BUGS
Some things are not yet implemented, or only implemented half-way:
inf handling (partial)
NaN handling (partial)
rounding (not implemented except for bceil/bfloor)
$x ** $y where $y is not an integer
LICENSE
This program is free software; you may redistribute it and/or modify it under the same terms as Perl itself.
SEE ALSO
Math::BigFloat and Math::Big as well as Math::BigInt::BitVect, Math::BigInt::Pari and Math::BigInt::GMP.
See <http://search.cpan.org/search?dist=bignum> for a way to use Math::BigRat.
The package at <http://search.cpan.org/search?dist=Math%3A%3ABigRat> may contain more documentation and examples as well as testcases.
AUTHORS
(C) by Tels <http://bloodgate.com/> 2001-2002.
perl v5.8.0 2002-06-01 Math::BigRat(3pm)