public SDVariable unsortedSegmentSum(SDVariable data, SDVariable segmentIds,
      SDVariable numSegments) {
    SDValidation.validateNumerical("unsortedSegmentSum", "data", data);
    SDValidation.validateNumerical("unsortedSegmentSum", "segmentIds", segmentIds);
    SDValidation.validateInteger("unsortedSegmentSum", "numSegments", numSegments);