Applies a softmax function.
nnf_softmax(input, dim, dtype = NULL)(Tensor) input
(int) A dimension along which softmax will be computed.
(torch.dtype, optional) the desired data type of returned tensor. If specified, the input tensor is casted to dtype before the operation is performed. This is useful for preventing data type overflows.
Default: NULL.
Softmax is defined as:
$$Softmax(x_{i}) = exp(x_i)/\sum_j exp(x_j)$$
It is applied to all slices along dim, and will re-scale them so that the elements
lie in the range [0, 1] and sum to 1.