def set_jac(self, m, val, row, col):
        """
        Set the values at (row, col) to val in Jacobian m

        :param m: Jacobian name
        :param val: values to set
        :param row: row indices
        :param col: col indices
        :return: None
        """
        assert m in ('Fx', 'Fy', 'Gx', 'Gy', 'Fx0', 'Fy0', 'Gx0', 'Gy0'), \
            'Wrong Jacobian matrix name <{0}>'.format(m)

        if isinstance(val,
                      (int, float)) and isinstance(row,
                                                   (np.ndarray, matrix, list)):
            val = val * ones(len(row), 1)

        self._set[m]['I'] = matrix([self._set[m]['I'], matrix(row)])
        self._set[m]['J'] = matrix([self._set[m]['J'], matrix(col)])
        self._set[m]['V'] = matrix([self._set[m]['V'], matrix(val)])