So if we look at the documentation for kl_div 7 we are instructed to See KLDivLoss 5 for details.
There it says:

the input given is expected to contain log-probabilities and is not restricted to a 2D Tensor. The targets are interpreted as probabilities by default, but could be considered as log-probabilities with log_target set to True.

In other words, the first argument should be log probs.
Personally, I’d not use FloatTensor, it’s been superseded as the preferred way to create tensors 3 longer than it had been the way to create them.
Best regards
Thomas