I used this:
        L1=geomloss.SamplesLoss()(ccc.unsqueeze(2),ccc1.unsqueeze(2))
        MSECMBSS=L1.sum()
       loss2 = MSECMBSS
       loss2.backward.()

here is the flow of the gradient. I think just last layer have gradient and the earliest layer doe snot have. the numbers are very small.