File Coverage

blib/lib/Math/nSphere.pm

Criterion	Covered	Total	%
statement	36	38	94.7
branch	8	12	66.6
condition			n/a
subroutine	6	6	100.0
pod	2	2	100.0
total	52	58	89.6

package Math::nSphere;

our $VERSION = '0.01';

use strict;
use warnings;
use Carp;

use Exporter qw(import);
our @EXPORT_OK = qw(nsphere_surface nsphere_volumen);

my $PI = 3.14159265358979323846264338327950288419716939937510;

my @S = ( 0 , 2 * $PI , 4 * $PI );
my @V = ( 0 ,       2 ,     $PI , 4 / 3 * $PI );

sub nsphere_surface {
    my ($n, $r) = @_;
    my $S = $S[$n];
    unless (defined $S) {
        $n = int $n;
        $n >= 0 or croak "index out of range";
        my $i = $n;
        $i -= 2 until defined $S[$i];
        $S = $S[$i];
        while ($i < $n) {
            $i += 2;
            $S[$i] = $S = 2 * $PI * $S / ($i - 1);
        }
    };
    return $S unless defined $r;
    $r ** $n * $S;
}

sub nsphere_volumen {
    my ($n, $r) = @_;
    my $V = $V[$n];
    unless (defined $V) {
        $n = int $n;
        $n >= 0 or croak "index out of range";
        my $i = $n;
        $i -= 2 until defined $V[$i];
        $V = $V[$i];
        while ($i < $n) {
            $i += 2;
            $V[$i] = $V = 2 * $PI * $V / $i;
        }
    };
    return $V unless defined $r;
    $r ** ($n + 1) * $V;
}

1;
__END__