label vector can not contain values larger than the size of the label vector

[rindis]

If you have a label vector y = [1 3], you will get the following error:

Error using sub2ind (line 55)
Out of range subscript.

Error in nnCostFunction (line 65)
idx = sub2ind([m num_labels],1:m,y');

[vtshitoyan]

Thanks for reporting this bug. I haven't been maintaining this repo properly since I haven't been using Matlab lately. If you've already got a fix, I'd appreciate a pull request.