Using dp.Confusion

[ssampang]

I'm having trouble using the Confusion module. I'm following the RAM example in the rnn package, and the only difference is that my output is of the form batchLen x seqLen x numClasses (as opposed to the RAM example which is simply batchLen x numClasses). I'm currently working with a seqLen of 4, and when i try to use a dp.Confusion{ nn.SelectTable(1) } for the feedback parameter, I get the following error:

==> epoch # 1 for optimizer :   
/home/sid/torch/install/bin/luajit: bad argument #2 to '?' (out of range at /tmp/luarocks_torch-scm-1-4568/torch7/generic/Tensor.c:890)
stack traceback:
    [C]: at 0x7fa33bd88980
    [C]: in function '__index'
    ...id/torch/install/share/lua/5.1/optim/ConfusionMatrix.lua:42: in function '_add'
    ...id/torch/install/share/lua/5.1/optim/ConfusionMatrix.lua:106: in function 'batchAdd'
    ...id/torch/install/share/lua/5.1/dp/feedback/confusion.lua:83: in function '_add'
    ...sid/torch/install/share/lua/5.1/dp/feedback/feedback.lua:63: in function 'add'
    ...torch/install/share/lua/5.1/dp/propagator/propagator.lua:175: in function 'monitor'
    .../torch/install/share/lua/5.1/dp/propagator/optimizer.lua:51: in function 'propagateBatch'
    ...torch/install/share/lua/5.1/dp/propagator/propagator.lua:127: in function 'propagateEpoch'
    ...torch/install/share/lua/5.1/dp/propagator/experiment.lua:110: in function 'run'
    recurrent-visual-attention.lua:310: in main chunk
    [C]: in function 'dofile'
    .../sid/torch/install/lib/luarocks/rocks/trepl/scm-1/bin/th:145: in main chunk
    [C]: at 0x00406670