Question about unused 'registerer' variable


I’m reading the PyTorch source code after that the PyTorch package is installed in python.

There is unused(I guess) variable named ‘registerer’ in torch/csrc/autograd/generated/VariableType_{0, 1, 2, 3}.cpp. But i think this variable is important for registering tensor operations.

Does anyone know where the ‘registerer’ variable work?

Or is there any effective debugging method for PyTorch c++ source code?