More advanced rescaling by inputs

[jlperla]

If we find that we want more control over what inputs are rescaled, then something like

class RescaleInputsbyInput(nn.Module):
    def __init__(self, rescale_index, inputs_to_rescale = None):
        super().__init__()
        self.rescale_index = rescale_index

        # if inputs_to_rescale is None, then it assume all except the current one.
        if inputs_to_rescale is None:
            self.inputs_to_rescale = # generate all indices except the rescale_index one.
       else:
           self.inputs_to_rescale = inputs_to_rescale
        
    def forward(self, x):
        rescale_scalar = 1 / x[self.rescale_index]        
        new_x = # multiple all indices in "inputs_to_rescale" by "rescale_scalar".
        return new_x