Math::BigRat(3p)Perl Programmers Reference Guide Math::BigRat(3p)
Math::BigRat - Arbitrary big rational numbers
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();
Math::BigRat complements Math::BigInt and Math::BigFloat by
providing support for arbitrary big rational numbers.
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 documen-
tation 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
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Any methods not listed here are dervied 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.
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as_int()
$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_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.
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.
blog()
Is not yet implemented.
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);
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Set $x to the remainder of the division of $x by $y.
is_one()
print "$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 $x is exactly zero, otherwise false.
is_pos()
print "$x is >= 0\n" if $x->is_positive();
Return true if $x is positive (greater than or equal to
zero), otherwise false. Please note that '+inf' is also
positive, while 'NaN' and '-inf' aren't.
"is_positive()" is an alias for "is_pos()".
is_neg()
print "$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();
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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.
config
use Data::Dumper;
print Dumper ( Math::BigRat->config() );
print Math::BigRat->config()->{lib},"\n";
Returns a hash containing the configuration, e.g. the ver-
sion number, lib loaded etc. The following hash keys are
currently filled in with the appropriate information.
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Math::BigRat(3p)Perl Programmers Reference Guide Math::BigRat(3p)
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 acccuracy 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 configura-
tion values. This works only for values that a marked with a
"RW" above, anything else is read-only.
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)
This program is free software; you may redistribute it
and/or modify it under the same terms as Perl itself.
Math::BigFloat and Math::Big as well as
Math::BigInt::BitVect, Math::BigInt::Pari and
Math::BigInt::GMP.
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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 test-
cases.
(C) by Tels <http://bloodgate.com/> 2001 - 2005.
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