elemwise.py 文件源码

def grad(self, inp, grads):
        x, = inp

        out = self(*inp)

        if out.dtype.find('int') != -1:
            return [x.zeros_like(dtype=theano.config.floatX)]

        gz, = grads
        gz = as_tensor_variable(gz)
        axis = self.axis
        if axis is None:
            axis = list(range(x.type.ndim))
        if axis == ():
            return gz,
        new_dims = []
        i = 0
        for j, _ in enumerate(x.type.broadcastable):
            if j in axis:
                new_dims.append('x')
            else:
                new_dims.append(i)
                i += 1
        ds_op = DimShuffle(gz.type.broadcastable, new_dims)
        gx = Elemwise(scalar.second)(x, ds_op(gz))
        return [gx]