@Override
    public TensorFunction<NAMETYPE> withArguments(List<TensorFunction<NAMETYPE>> arguments) {
        if (arguments.size() != 2)
            throw new IllegalArgumentException("Concat must have 2 arguments, got " + arguments.size());
        return new Concat<>(arguments.get(0), arguments.get(1), dimension);
    }
Concatenation of two tensors along an (indexed) dimension

@author bratseth
vespajlib/src/main/java/com/yahoo/tensor/functions/Concat.java