@Override
    protected TensorFunction<Reference> lazyGetFunction() {
        if ( ! allInputFunctionsPresent(1)) return null;
        List<String> reduceDimensions = reduceDimensions();
        TensorFunction<Reference> input = inputs.get(0).function().get();
        TensorFunction<Reference> sum = new Reduce<>(input, Reduce.Aggregator.sum, reduceDimensions);
        TensorFunction<Reference> div = new Join<>(input, sum, ScalarFunctions.divide());
        return div;
    }
Convert imported 'softmax' operation to the Vespa softmax ranking function.

@author lesters
model-integration/src/main/java/ai/vespa/rankingexpression/importer/operations/Softmax.java