FractionalMaxPool2d

Now I know input,Kernel_size and outputsize ,How do I calculate pad and stride, to get the output of this layer

FractionalMaxPool2d doesn’t have pad or stride parameters.

torch.nn.FractionalMaxPool2d(kernel_size, output_size=None, output_ratio=None, return_indices=False, _random_samples=None)

torch.nn.FractionalMaxPool2d ,How this function is calculated, I want to implement it myself.