sub by_string {
  my $n = shift;
  return length(sprintf "%b", $n) - 1;
}

##</code><code>##

log    linear sprintf
0.2917 0.4427 0.3370  avg_sig=62
0.2786 2.8430 0.3056  avg_sig=30
0.2826 4.1060 0.2986  avg_sig=14