What change was made to ColumnarDataset?
I see the one commented line but it looks the same as fastai version except your y input is a df and fastai uses np.array.
And what change to make it multiple classification?
I have similar setup for different dataset and have this error:
RuntimeError: multi-target not supported at /opt/conda/conda-bld/pytorch_1518244421288/work/torch/lib/THNN/generic/ClassNLLCriterion.c:22
This is running learn.fit
Which seems to be some dimension error in the target(y) somewhere. The dimension was BatchSize x 1 with each an int for the category.