Why expose the softmax and sigmoid parameters on the DiceFocalLoss if by default the FocalLoss works only with logits?

[ramonemiliani93]

Hi, I find it confusing that the softmax and sigmoid parameters are exposed on the DiceFocalLoss if by default it has to work with the logits, as per the documentation:

input: the shape should be BNH[WD]. The input should be the original logits
                due to the restriction of ``monai.losses.FocalLoss``.

Is there a specific reason for not removing the parameters? I feel this may lead to bugs on user code.

[Nic-Ma]

Hi @ramonemiliani93 ,

The DiceFocalLoss is a hybrid loss function with DiceLoss and FocalLoss, the activation parameter is used in the DiceLoss of DiceFocalLoss.
Let me try to enhance the doc-string to make it more clear later.

Thanks.

[Nic-Ma]

Submitted PR #2614 for it.
Thanks.