torch.Tensor.index_fill_
Tensor.index_fill_(dim, index, value) -> Tensor
Fills the elements of the "self" tensor with value "value" by
   selecting the indices in the order given in "index".
Parameters:
      * dim (int) -- dimension along which to index
  * **index** (*LongTensor*) -- indices of "self" tensor to fill
    in

  * **value** (*float*) -- the value to fill with

Example::
      >>> x = torch.tensor([[1, 2, 3], [4, 5, 6], [7, 8, 9]], dtype=torch.float)
      >>> index = torch.tensor([0, 2])
      >>> x.index_fill_(1, index, -1)
      tensor([[-1.,  2., -1.],
              [-1.,  5., -1.],
              [-1.,  8., -1.]])