torch.atan2
torch.atan2(input, other, *, out=None) -> Tensor
Element-wise arctangent of \text{input}{i} / \text{other} with
   consideration of the quadrant. Returns a new tensor with the signed
   angles in radians between vector (\text{other}{i},
   \text{input}) and vector (1, 0). (Note that \text{other}{i},
   the second parameter, is the x-coordinate, while \text{input},
   the first parameter, is the y-coordinate.)
The shapes of "input" and "other" must be broadcastable.
Parameters:
      * input (Tensor) -- the first input tensor
  * **other** (*Tensor*) -- the second input tensor

Keyword Arguments:
      out (Tensor, optional) -- the output tensor.
Example:
  >>> a = torch.randn(4)
  >>> a
  tensor([ 0.9041,  0.0196, -0.3108, -2.4423])
  >>> torch.atan2(a, torch.randn(4))
  tensor([ 0.9833,  0.0811, -1.9743, -1.4151])
