def _reverse_act(self):
        for row in list(range(self.n))[::-1]:
            diagonal_element = self._matrix[row][row]

            left_part = 0
            for column in range(row, self.n):
                if row != column:
                    left_part += self._matrix[row][column] * self._free_members[column]
                    self._matrix[row][column] = 0
                else:
                    self._matrix[row][row] /= diagonal_element

            left_part /= diagonal_element
            self._free_members[row] /= diagonal_element
            self._free_members[row] -= left_part