representation (input, tau) of matrix Q from the QR
     decomposition.
Note:
 This function supports backward but it is only fast when "(input,
 tau)" do not require gradients and/or "tau.size(-1)" is very
 small. ``

Parameters:
      * input (Tensor) -- tensor of shape (, mn, k) where ***
        is zero or more batch dimensions and mn equals to m or n*
        depending on the "left".
  * **tau** (*Tensor*) -- tensor of shape *(*, min(mn, k))* where
    *** is zero or more batch dimensions.

  * **other** (*Tensor*) -- tensor of shape *(*, m, n)* where ***
    is zero or more batch dimensions.

  * **left** (*bool*) -- controls the order of multiplication.

  * **transpose** (*bool*) -- controls whether the matrix *Q* is
    conjugate transposed or not.

Keyword Arguments:
      out (Tensor, optional) -- the output Tensor. Ignored
      if None. Default: None.