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 low-level 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()
$x->bneg();
Used to negate the object in-place.
is_one()
print "$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!(n-k)!
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 read-only.
objectify()
This is an internal routine that turns scalars into objects.
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
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 AT leto.net>
<http://leto.net>;
perl v5.16.3 2013-03-04 Math::BigRat(3pm)
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