class VariableValues {

    public static double dotProduct(Map<? extends VariableReference, DoubleTensor> left, Map<? extends VariableReference, DoubleTensor> right) {
        double dotProduct = 0.0;
        for (VariableReference v : left.keySet()) {
            dotProduct += left.get(v).times(right.get(v)).sumNumber();
        }
        return dotProduct;
    }

    private  VariableValues();

}