Hi,
If I get that right, you want to sum over all values in your hash, right?
If so you can use something like this:

my %h=(ab=>"12",
       ac=>"14",
       ad=>"45");
my $sum;
foreach (values(%h)) {
    my $log2 = &log_2($_);
    $sum +=$log2;
}
print "$sum \n";
[download]

si_lence