
Math::BigRat(3pm) Perl Programmers Reference Guide Math::BigRat(3pm)
NAME
Math::BigRat  Arbitrary big rational numbers
SYNOPSIS
use Math::BigRat;
my $x = Math::BigRat>new('3/7'); $x += '5/9';
print $x>bstr(),"\n";
print $x ** 2,"\n";
my $y = Math::BigRat>new('inf');
print "$y ", ($y>is_inf ? 'is' : 'is not') , " infinity\n";
my $z = Math::BigRat>new(144); $z>bsqrt();
DESCRIPTION
Math::BigRat complements Math::BigInt and Math::BigFloat by providing support for
arbitrary big rational numbers.
MATH LIBRARY
You can change the underlying module that does the lowlevel math operations by using:
use Math::BigRat try => 'GMP';
Note: This needs Math::BigInt::GMP installed.
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 try => 'Foo,Math::BigInt::Bar';
If you want to get warned when the fallback occurs, replace "try" with "lib":
use Math::BigRat lib => 'Foo,Math::BigInt::Bar';
If you want the code to die instead, replace "try" with "only":
use Math::BigRat only => 'Foo,Math::BigInt::Bar';
METHODS
Any methods not listed here are derived from Math::BigFloat (or Math::BigInt), so make
sure you check these two modules for further information.
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('inf'); # infinity
$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
# You can also give D and N as different objects:
$x = Math::BigRat>new(
Math::BigInt>new(123),
Math::BigInt>new(7),
); # => 123/7
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.
numify()
my $y = $x>numify();
Returns the object as a scalar. This will lose some data if the object cannot be
represented by a normal Perl scalar (integer or float), so use as_int() or as_float()
instead.
This routine is automatically used whenever a scalar is required:
my $x = Math::BigRat>new('3/1');
@array = (0,1,2,3);
$y = $array[$x]; # set $y to 3
as_int()/as_number()
$x = Math::BigRat>new('13/7');
print $x>as_int(),"\n"; # '1'
Returns a copy of the object as BigInt, truncated to an integer.
"as_number()" is an alias for "as_int()".
as_float()
$x = Math::BigRat>new('13/7');
print $x>as_float(),"\n"; # '1'
$x = Math::BigRat>new('2/3');
print $x>as_float(5),"\n"; # '0.66667'
Returns a copy of the object as BigFloat, preserving the accuracy as wanted, or the
default of 40 digits.
This method was added in v0.22 of Math::BigRat (April 2008).
as_hex()
$x = Math::BigRat>new('13');
print $x>as_hex(),"\n"; # '0xd'
Returns the BigRat as hexadecimal string. Works only for integers.
as_bin()
$x = Math::BigRat>new('13');
print $x>as_bin(),"\n"; # '0x1101'
Returns the BigRat as binary string. Works only for integers.
as_oct()
$x = Math::BigRat>new('13');
print $x>as_oct(),"\n"; # '015'
Returns the BigRat as octal string. Works only for integers.
from_hex()/from_bin()/from_oct()
my $h = Math::BigRat>from_hex('0x10');
my $b = Math::BigRat>from_bin('0b10000000');
my $o = Math::BigRat>from_oct('020');
Create a BigRat from an hexadecimal, binary or octal number in string form.
length()
$len = $x>length();
Return the length of $x in digits for integer values.
digit()
print Math::BigRat>new('123/1')>digit(1); # 1
print Math::BigRat>new('123/1')>digit(1); # 3
Return the N'ths digit from X when X is an integer value.
bnorm()
$x>bnorm();
Reduce the number to the shortest form. This routine is called automatically whenever it
is needed.
bfac()
$x>bfac();
Calculates the factorial of $x. For instance:
print Math::BigRat>new('3/1')>bfac(),"\n"; # 1*2*3
print Math::BigRat>new('5/1')>bfac(),"\n"; # 1*2*3*4*5
Works currently only for integers.
bround()/round()/bfround()
Are not yet implemented.
bmod()
use Math::BigRat;
my $x = Math::BigRat>new('7/4');
my $y = Math::BigRat>new('4/3');
print $x>bmod($y);
Set $x to the remainder of the division of $x by $y.
bneg()
$x>bneg();
Used to negate the object inplace.
is_one()
print "$x is 1\n" if $x>is_one();
Return true if $x is exactly one, otherwise false.
is_zero()
print "$x is 0\n" if $x>is_zero();
Return true if $x is exactly zero, otherwise false.
is_pos()/is_positive()
print "$x is >= 0\n" if $x>is_positive();
Return true if $x is positive (greater than or equal to zero), otherwise false. Please
note that '+inf' is also positive, while 'NaN' and 'inf' aren't.
"is_positive()" is an alias for "is_pos()".
is_neg()/is_negative()
print "$x is < 0\n" if $x>is_negative();
Return true if $x is negative (smaller than zero), otherwise false. Please note that
'inf' is also negative, while 'NaN' and '+inf' aren't.
"is_negative()" is an alias for "is_neg()".
is_int()
print "$x is an integer\n" if $x>is_int();
Return true if $x has a denominator of 1 (e.g. no fraction parts), otherwise false. Please
note that 'inf', 'inf' and 'NaN' aren't integer.
is_odd()
print "$x is odd\n" if $x>is_odd();
Return true if $x is odd, otherwise false.
is_even()
print "$x is even\n" 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.
bsqrt()
$x>bsqrt();
Calculate the square root of $x.
broot()
$x>broot($n);
Calculate the N'th root of $x.
badd()/bmul()/bsub()/bdiv()/bdec()/binc()
Please see the documentation in Math::BigInt.
copy()
my $z = $x>copy();
Makes a deep copy of the object.
Please see the documentation in Math::BigInt for further details.
bstr()/bsstr()
my $x = Math::BigInt>new('8/4');
print $x>bstr(),"\n"; # prints 1/2
print $x>bsstr(),"\n"; # prints 1/2
Return a string representing this object.
bacmp()/bcmp()
Used to compare numbers.
Please see the documentation in Math::BigInt for further details.
blsft()/brsft()
Used to shift numbers left/right.
Please see the documentation in Math::BigInt for further details.
bpow()
$x>bpow($y);
Compute $x ** $y.
Please see the documentation in Math::BigInt for further details.
bexp()
$x>bexp($accuracy); # calculate e ** X
Calculates two integers A and B so that A/B is equal to "e ** $x", where "e" is Euler's
number.
This method was added in v0.20 of Math::BigRat (May 2007).
See also blog().
bnok()
$x>bnok($y); # x over y (binomial coefficient n over k)
Calculates the binomial coefficient n over k, also called the "choose" function. The
result is equivalent to:
( n ) n!
   = 
( k ) k!(nk)!
This method was added in v0.20 of Math::BigRat (May 2007).
config()
use Data::Dumper;
print Dumper ( Math::BigRat>config() );
print Math::BigRat>config()>{lib},"\n";
Returns a hash containing the configuration, e.g. the version number, lib loaded etc. The
following hash keys are currently filled in with the appropriate information.
key RO/RW Description
Example
============================================================
lib RO Name of the Math library
Math::BigInt::Calc
lib_version RO Version of 'lib'
0.30
class RO The class of config you just called
Math::BigRat
version RO version number of the class you used
0.10
upgrade RW To which class numbers are upgraded
undef
downgrade RW To which class numbers are downgraded
undef
precision RW Global precision
undef
accuracy RW Global accuracy
undef
round_mode RW Global round mode
even
div_scale RW Fallback accuracy for div
40
trap_nan RW Trap creation of NaN (undef = no)
undef
trap_inf RW Trap creation of +inf/inf (undef = no)
undef
By passing a reference to a hash you may set the configuration values. This works only for
values that a marked with a "RW" above, anything else is readonly.
objectify()
This is an internal routine that turns scalars into objects.
BUGS
Some things are not yet implemented, or only implemented halfway:
inf handling (partial)
NaN handling (partial)
rounding (not implemented except for bceil/bfloor)
$x ** $y where $y is not an integer
bmod(), blog(), bmodinv() and bmodpow() (partial)
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  2009.
Currently maintained by Jonathan "Duke" Leto <jonathan@leto.net> <http://leto.net>
perl v5.16.3 20130304 Math::BigRat(3pm) 
