How nngraph works?

[SergeyMalashenko]

I implemented two equal networks. The first one uses only nn modules, the second one uses nngraph. I compared performance and I found that nngraph implementation works in two times lower. Why?

[Max Schwarz]

Hard to tell, since you did not provide any details ;-)

You could show your source code, or, even better, you could try to create a minimal example where the problem can be seen.