public INDArray sparseSoftmaxCrossEntropy(INDArray logits, INDArray labels) {
    NDValidation.validateNumerical("sparseSoftmaxCrossEntropy", "logits", logits);
    NDValidation.validateInteger("sparseSoftmaxCrossEntropy", "labels", labels);
    return Nd4j.exec(new org.nd4j.linalg.api.ops.impl.loss.SparseSoftmaxCrossEntropyLossWithLogits(logits, labels))[0];
  }