attempt to call method 'topk' (a nil value)

[sivagnanamn]

I trained the model with a different dataset ( but in the same format as movie conversations) using "opencl". While evaluating I'm getting the below error.

me: say "Hello."

./seq2seq.lua:122: attempt to call method 'topk' (a nil value)
stack traceback:
    ./seq2seq.lua:122: in function 'eval'
    eval.lua:74: in function 'say'
    [string "_RESULT={say "Hello."}"]:1: in main chunk
    [C]: in function 'xpcall'
    /home/siva/torch-cl/install/share/lua/5.1/trepl/init.lua:651: in function 'repl'
    ...d/torch-cl/install/lib/luarocks/rocks/trepl/scm-1/bin/th:199: in main chunk
    [C]: at 0x00406670  

Printing the prediction tensor size gives the below output:

Prediction tensor size:      141874
[torch.LongStorage of size 1]