#! perl -slw
use strict;
use Time::HiRes qw[ time ];


sub MI {
    my( $string_es, $string_en, $hash_es, $hash_en ) = @_;

    my $n_es = unpack '%32b*', $hash_es->{ $string_es };
    my $n_en = unpack '%32b*', $hash_en->{ $string_en };

    my $prob_es = ( $n_es ) / 6939873;
    my $prob_en = ( $n_en ) / 6939873;

    my $intersection = unpack '%32b*',
        $hash_es->{ $string_es } & $hash_es->{ $string_es };

    my $prob_es_en=  $intersection / 6939873;

    $prob_es_en = ( $prob_es_en + ( $prob_es * $prob_en * 0.1 ) ) / 1.1;
    my $mi = $prob_es_en * log( $prob_es_en / ( $prob_es * $prob_en) );

    return $mi;
}


our $N //= 1e4;

my $hypo = 'fred';
my $text = 'bill';

my %hash_es; $hash_es{ $hypo } = '';
vec( $hash_es{ $hypo }, $_, 1 ) = 1 for 1 .. $N;

my %hash_en; $hash_en{ $text } = '';
vec( $hash_en{ $text }, $_, 1 ) = 1 for 1 .. $N;


my $start = time;
my $MI_T = MI( $hypo, $text, \%hash_es, \%hash_en );
printf "Took: %f seconds\n", time() - $start;

__END__
C:\test>888162 -N=3e6
Took: 0.001901 seconds