Error on THNN.lua

[Fernando Fernandes Neto]

I'm playing with character recognitions on images. Specifically, I'm studying how safe are the most used CAPTCHAs.

I've successfully implemented a VGG architecture using the CNN package and tested against a set of CAPTCHA images.

Then, I'm trying to train again my CNN using another set, and I'm getting the following error:

/torch/install/share/lua/5.1/nn/THNN.lua:110: Assertion `cur_target >= 0 && cur_target < n_classes' failed.  at /tmp/luarocks_nn-scm-1-6864/nn/lib/THNN/generic/ClassNLLCriterion.c:62

stack traceback:

[C]: in function 'v'

/home/fernando/torch/install/share/lua/5.1/nn/THNN.lua:110: in function 'ClassNLLCriterion_updateOutput'

...ndo/torch/install/share/lua/5.1/nn/ClassNLLCriterion.lua:41: in function 'updateOutput'

...torch/install/share/lua/5.1/nn/CrossEntropyCriterion.lua:20: in function 'updateOutput'

Does anyone has any thoughts on that?

It is also important to notice that, sometimes my training runs 2 or 3 batches before crashing, using this new dataset.

Any idea of what might be causing it?

Best Regards,

Fernando Fernandes