torch/nngraph — pull request #25 by fidlej (2014-03-14 11:43:14+00:00)
Title: Disallowed to use Identity()(nil)

I added error checking to `Module:__call__(input)`.
The input should never be nil.

The lines following will raise an error:

nn.Identity()(nil)
local var
nn.Identity()(var)

The following will work normally:

nn.Identity()()