code: public int[] getSparseIndices(int component) {
      assert (sparse[component]);
      int[] indices = new int[pointers[component].length / 2];
      for (int i = 0; i < pointers[component].length / 2; i++) {
        indices[i] = (int) pointers[component][i * 2];
      }
      return indices;
    }
docs: Gets you the indices of multi hot in a component, assuming it is sparse. Throws an assert if it isn't.
  
  @param component the index of the sparse component.
  @return the index of the one-hot value within that sparse component.