@fmassa thank you so much for the reply and the references. So if we do inputTensor1 + inputTensor2 , the above C++ / CUDA implementations are called ,am I correct? Also I did a simple experiment.  To make sure the function is called , a print command was included in the function and I ran the below code
import torch
import torch.legacy.nn as nn
x = torch.Tensor(2,2)
x.fill_(4.0)
y = torch.Tensor(2,2)
y.fill_(3.0)
out = nn.CAddTable().forward([x,y]) ( I know this command is obsolete now in pytorch 0.4)
and it didn’t print anything. Hence I was wondering if there are any other implementations for add function
I will recheck if I have made any mistake.