Comparing float values

compareFloatValues.php

// look into http://php.net/manual/en/language.types.float.php
function compareFloatValues($a, $b, $operator = '==')
{

    // This value is known as the machine epsilon, or unit roundoff, and is the smallest acceptable difference in calculations.
    $epsilon = 0.00001;

    // make equal to 5 digits of precision
    $a = (float)$a;
    $b = (float)$b;

    switch ($operator) {
            // must be repeated exactly
        case '==':
        case '===':
            if (abs($a - $b) < $epsilon) {
                return true;
            }
            break;

            // must not be equal to
        case "!=":
        case '!==':
            if (abs($a - $b) > $epsilon) {
                return true;
            }
            break;

            // must be less than
        case "<":
            if (abs($a - $b) < $epsilon) {
                return false;
            } else {
                if ($a < $b) {
                    return true;
                }
            }
            break;

            // must be greater than
        case ">":
            if (abs($a - $b) < $epsilon) {
                return false;
            } else {
                if ($a > $b) {
                    return true;
                }
            }
            break;

            // must be less than or equal to
        case "<=":
            if (compareFloatValues($a, $b, '<') || compareFloatValues($a, $b, '==')) {
                return true;
            }
            break;

            // must be greater than or equal to
        case ">=":
            if (compareFloatValues($a, $b, '>') || compareFloatValues($a, $b, '==')) {
                return true;
            }
            break;
        default:
            return false;
    }
}