Here’s the surprisingly simple solution to a fairly challenging problem. I do not understand why PHPs GMP extension does not include a gmp_not() function. function gmp_not($n) { # convert to binary string $n = gmp_strval($n, 2); # invert each bit, one at a time for($i = 0; $i < strlen($n); $i++) { $n[$i] = ~$n[$i]; } # convert back to decimal return gmp_strval(gmp_init($n, 2), [...]

So far so good on my experimental switch to Ubuntu Linux from Windows XP. I’m running 64-bit linux because my laptop’s Intel CPU supports it. However, many but not all programs available for linux are available in 64-bit versions. Last few days I’ve needed to install a few programs that don’t have 64-bit versions available, namely, [...]