torch.argmin
torch.argmin(input, dim=None, keepdim=False) -> LongTensor
Returns the indices of the minimum value(s) of the flattened tensor
   or along a dimension
This is the second value returned by "torch.min()". See its
   documentation for the exact semantics of this method.
Note:
 If there are multiple minimal values then the indices of the
 first minimal value are returned.

Parameters:
      * input (Tensor) -- the input tensor.
  * **dim** (*int*) -- the dimension to reduce. If "None", the
    argmin of the flattened input is returned.

  * **keepdim** (*bool*) -- whether the output tensor has "dim"
    retained or not..

Example:
  >>> a = torch.randn(4, 4)
  >>> a
  tensor([[ 0.1139,  0.2254, -0.1381,  0.3687],
          [ 1.0100, -1.1975, -0.0102, -0.4732],
          [-0.9240,  0.1207, -0.7506, -1.0213],
          [ 1.7809, -1.2960,  0.9384,  0.1438]])
  >>> torch.argmin(a)
  tensor(13)
