The document discusses using the Math::BigFloat module in Perl to perform arithmetic operations with large or precise numbers. It compares the performance of Math::BigFloat to regular floating point arithmetic and to the MPFR library in C. Benchmark tests show Math::BigFloat is much slower than regular floating point but faster than MPFR.

4. 3.14159 26535 89793 23846 26433 83279 50288.....

23. use Math::BigFloat;
my $x = Math::BigFloat->new(‘3.1415...’);
my $y = Math::BigFloat->new(‘2.718281...’);
my $z = $x * $y;

24. #
my $pi = Math::BigFloat->new(3.141592...);
#
my $pi = Math::BigFloat->new(‘3.141592...’);

26. use strict;
use Math::BigFloat;
use Benchmark qw(cmpthese);
cmpthese -1, {
plain => sub {
my $x = rand(10);
my $y = rand(10);
my $z = rand(10);
($x + $y ) * $z;
},
bigfloat => sub {
my $x = rand(10);
my $y = rand(10);
my $z = rand(10);
(Math::BigFloat->new($x)
+ Math::BigFloat->new($y))
* Math::BigFloat->new($z);
},
};

27. daisuke@beefcake ~$ perl foo.pl
Rate bigfloat plain
bigfloat 3380/s -- -100%
plain 2383127/s 70403% --
daisuke@beefcake ~$ perl foo.pl
Rate bigfloat plain
bigfloat 3380/s -- -100%
plain 2360644/s 69738% --
daisuke@beefcake ~$ perl foo.pl
Rate bigfloat plain
bigfloat 3380/s -- -100%
plain 2406041/s 71081% --

28. > perl benchmark.pl
Rate bigfloat plain
bigfloat 3901/s -- -100%
plain 2338582/s 59849% --

29. •DateTime::Util::Calc
•DateTime::Util::Astro
•DateTime::Event::Lunar

37. my $v = ( $x + $y ) * $z;
#include <mpfr.h>
mpfr_t x, y, z, w;
mpfr_add( w, x, y, MPFR_RNDN );
mpfr_mul( w, w, z, MPFR_RNDN );

38. mpfr_add( w, x, y, MPFR_RNDN );

42. s/iter bigint xs
bigint 2.58 -- -98%
mpfr 4.70e-02 5394% --