@ptrblck thanks for your reply.
I am using Cross Entropy Loss as criterion. Last non Linearity in my model is Softmax across dimension=1 ie. across the channels[else i can say across the depth].
In my case my model outputs[batch_size,2,32,32,32]. So i took softmax across dim=1.
PS: Your answers always helps.And this gives me motivation to carry further my work.Thanks to you.