use strict;
use warnings;
use Benchmark qw/cmpthese/;
use Data::Dumper;
use Clone qw/clone/;

my @matrix = map { 
    [
        map { int( rand( 100 ) ) } 0 .. 99
    ]
} 0 .. 99;
cmpthese(
    1000,
    {
        onemap  => sub{ my $result =  onemap( \@matrix ); },
        twomaps => sub{ my $result = twomaps( \@matrix ); },
        clone   => sub{ my $result =   clone( \@matrix ); },
    }
);

sub onemap {
    my $matrix = shift;
    return {
        Matrix => [
            map {
                [
                    @$_
                ]
            } @$matrix
        ]
    };
}

sub twomaps {
    my $matrix = shift;
    return {
        Matrix => [ 
            map { 
                my $row = $_; 
                [ 
                    map { ( $_ ); } @$row 
                ] 
            } @$matrix 
        ] 
    };
}

__END__
          Rate   clone twomaps  onemap
clone    107/s      --    -78%    -93%
twomaps  475/s    344%      --    -70%
onemap  1562/s   1362%    229%      --