Issue when using Guided Alignment

[Anupama94]

Hi,
When training the model with guided alignment, I get the following error.
./s2sa/data.lua:174: bad argument #2 to 'sub' (out of range at /home/anupama/torch/pkg/torch/generic/Tensor.c:304)
I have prepared the alignment file as suggested in the documentation.
Any suggestions to overcome this error?
Thank you.