extra_ops.py 文件源码

def grad(self, inp, cost_grad):
        """
        Notes
        -----
        The gradient is currently implemented for matrices only.

        """
        a, val = inp
        grad = cost_grad[0]
        if (a.dtype.startswith('complex')):
            return [None, None]
        elif a.ndim > 2:
            raise NotImplementedError('%s: gradient is currently implemented'
                                      ' for matrices only' %
                                      self.__class__.__name__)
        wr_a = fill_diagonal(grad, 0)  # valid for any number of dimensions
        # diag is only valid for matrices
        wr_val = theano.tensor.nlinalg.diag(grad).sum()
        return [wr_a, wr_val]