There is a more elegant way to do this :
// Recursive function to compute gcd (euclidian method)
function gcd ($a, $b) {
return $b ? gcd($b, $a % $b) : $a;
}
// Then reduce any list of integer
echo array_reduce(array(42, 56, 28), 'gcd'); // === 14
If you want to work with floating points, use approximation :
function fgcd ($a, $b) {
return $b > .01 ? fgcd($b, fmod($a, $b)) : $a; // using fmod
}
echo array_reduce(array(2.468, 3.7, 6.1699), 'fgcd'); // ~= 1.232
You can use a closure in PHP 5.3 :
$gcd = function ($a, $b) use (&$gcd) { return $b ? $gcd($b, $a % $b) : $a; };