torch.Tensor.masked_fill_
Tensor.masked_fill_(mask, value)
Fills elements of "self" tensor with "value" where "mask" is True.
   The shape of "mask" must be broadcastable with the shape of the
   underlying tensor.
Parameters:
      * mask (BoolTensor) -- the boolean mask
  * **value** (*float*) -- the value to fill in with
