Please restore the original interface where we specified the exact number of entries per row to initialize. The strategy behind Martens' sparse intialization method is that you use the same number of non-zero entries regardless of the layer size, so that the total amount of weights is about the same everywhere. Usually you just initialize every layer to have exactly 15 non-zero elements. If you have to do division to figure out the right proportion at every layer, that defeats a lot of the point. If you want to keep the "sparseness" float that's fine; you can make two different optional arguments. But I don't want you to get rid of the one I already had.