public function mprint($A, $format='%01.2f', $width=2)
    {
        $spacing = '';
        $m = count($A);
        $n = count($A[0]);
        for ($i = 0; $i < $width; $i++) {
            $spacing .= '&nbsp;';
        }
        for ($i = 0; $i < $m; $i++) {
            for ($j = 0; $j < $n; $j++) {
                $formatted = sprintf($format, $A[$i][$j]);
                echo $formatted . $spacing;
            }
            echo '<br />';
        }
    }