temporal_softmax.py 文件源码

def backward(self):

        dx_flat = self.probs

        coords = tf.transpose(tf.pack([tf.range(self.N * self.T), self.y_flat]))
        binary_mask = tf.sparse_to_dense(coords, dx_flat.get_shape(), 1)
        # convert 1/0 to True/False
        binary_mask = tf.cast(binary_mask, tf.bool)
        decremented = dx_flat - 1
        # make new x out of old values or decresed, depending on mask 
        dx_flat = tf.select(binary_mask, decremented, dx_flat)
        dx_flat /= self.N
        dx_flat *= self.mask_flat[:, None]

        dx = tf.reshape(dx_flat, [self.N, self.T, self.V])

        return dx