#!/usr/bin/env perl

use strict;
use warnings;

use PDL;
use Benchmark qw(:all);

cmpthese(
    500,
    {   'pdl_values'  => sub {&pdl_value},
        'perl_values' => sub {&perl_scalar_value},
        'perl_array' => sub {&perl_array},
    }
);


exit;

sub pdl_value {
    my $pdl = ones( float, 10000 );
    $pdl->index(0) .= 999;
    my $nelem         = nelem($pdl);
    my $special_value = 999;

    my @values;
    for ( my $i = 0; $i < $nelem; ++$i ) {
        my $val = $pdl->index($i);
        if ( $val == $special_value ) {
            $val = undef;
        }
        push @values, $val;
    }

    #Do something with @values
    return;
}

sub perl_scalar_value {
    my $pdl = ones( float, 10000 );
    $pdl->index(0) .= 999;
    my $nelem         = nelem($pdl);
    my $special_value = 999;

    my @values;
    for ( my $i = 0; $i < $nelem; ++$i ) {
        my $val = $pdl->at($i);
        if ( $val == $special_value ) {
            $val = undef;
        }
        push @values, $val;
    }

    #Do something with @values
    return;
}

sub perl_array {
    my $pdl = ones( float, 10000 );
    $pdl->index(0) .= 999;
    my $nelem         = nelem($pdl);
    my $special_value = 999;

    my @perl_array = list $pdl;

    my @values = map { $_ == $special_value ? '' : $_ } @perl_array;  

    #Do something with @values
    return;
}
[download]