Hi, Thanks for the reply!
So, the error is defined as,
ce_n = cross-entropy loss of subgroup n
f1 = torch.tensor([1/ce_1, 1/ce_2, 1/ce_3])
f2 = torch.tensor([1/ce_4, 1/ce_5, 1/ce_6])
error = 1 - f1/f2
The gradient of loss2 always seems to be zero. Could you please help me figure out why?