public INDArray unsortedSegmentSum(INDArray data, INDArray segmentIds, int numSegments) {
    NDValidation.validateNumerical("unsortedSegmentSum", "data", data);
    NDValidation.validateNumerical("unsortedSegmentSum", "segmentIds", segmentIds);
    return Nd4j.exec(new org.nd4j.linalg.api.ops.impl.transforms.segment.UnsortedSegmentSum(data, segmentIds, numSegments))[0];
  }