Variable Length Extension of torch.nn

There is also a CUDA Version of this library to support GPU.

To install this library, you could just use the following command if you have installed luarocks:
luarocks install https://raw.githubusercontent.com/anoidgit/lenn/master/rocks/lenn-scm-1.rockspec

The input of this module should be a Lua Table, it consists of 2 elements, the first one is the input matrix of batchsize*seqlen to apply softmax function, the second one should be a vector with batchsize dimension, the number in each dimension is the actual length to calculate softmax with the corresponding row in input matrix, data beyong that length will be filled with 0. The test script can be regarded as an example if you have problem in understanding how to use it.

The function of this module is similar with LenSoftMax, except that his module assumes that you pad in the head of the sequences, this may help make the implementation of seq2seq easier. The test script can be regarded as an example if you have problem in understanding how to use it.