public function set($i = null, $j = null, $c = null)
    {
        // Optimized set version just has this
        $this->A[$i][$j] = $c;
        /*
        if( is_int($i) && is_int($j) && is_numeric($c) ) {
          if( ( $i < $this->m ) && ( $j < $this->n ) ) {
            $this->A[$i][$j] = $c;
          } else {
            echo "A[$i][$j] = $c<br />";
            trigger_error(ArgumentBoundsException, WARNING);
          }
        } else {
          trigger_error(ArgumentTypeException, WARNING);
        }
        */
    }