code: public INDArray removeEntry(int idx) {
          values = shiftLeft(values, idx + 1, 1, length());
          indices = shiftLeft(indices, (int) (idx * shape.length() + shape.length()), (int) shape.length(),
                          indices.length());
          return this;
      }
docs: Remove an element of the ndarray
  @param idx the index of the element to be removed
  @return the ndarray