torch.flatten
torch.flatten(input, start_dim=0, end_dim=- 1) -> Tensor
Flattens "input" by reshaping it into a one-dimensional tensor. If
   "start_dim" or "end_dim" are passed, only dimensions starting with
   "start_dim" and ending with "end_dim" are flattened. The order of
   elements in "input" is unchanged.
Unlike NumPy's flatten, which always copies input's data, this
   function may return the original object, a view, or copy. If no
   dimensions are flattened, then the original object "input" is
   returned. Otherwise, if input can be viewed as the flattened shape,
   then that view is returned. Finally, only if the input cannot be
   viewed as the flattened shape is input's data copied. See
   "torch.Tensor.view()" for details on when a view will be returned.
Note:
 Flattening a zero-dimensional tensor will return a one-
 dimensional view.

Parameters:
      * input (Tensor) -- the input tensor.
  * **start_dim** (*int*) -- the first dim to flatten
