src/Maths/Algebra/Matrix.php
public function offsetGet($offset)
    {
        try {
            $res = $this
                ->seekToOffset($offset)
                ->current();
        } catch (OutOfRangeException $e) {
            $res = null;
            trigger_error("Undefined offset: '$offset'", E_USER_NOTICE);
        }
        return $res;
    }
public function offsetGet($offset)
    {
        try {
            $res = $this
                ->seekToOffset($offset)
                ->current();
        } catch (OutOfRangeException $e) {
            $res = null;
            trigger_error("Undefined offset: '$offset'", E_USER_NOTICE);
        }
        return $res;
    }
Get an offset value

@param   int/string   $offset
@return  mixed
@throws  Triggers a NOTICE message if the offset is out of range