test1.cpp:9:77: error: no match for call to ‘(const std::normal_distribution<double>) (std::mt19937&)’

Question

I have this code:

class Y {
    private:
        std::normal_distribution<double> N;
    public:
        Y() : N(0,1) {}
        double operator()(const double & x, std::mt19937 G) const { return x + N(G); }
};

And I have this error:

error: no match for call to '(const std::normal_distribution) (std::mt19937&)'

for the line:

    double operator()(const double & x, std::mt19937 G) const { return x + N(G); }

Answer 1

Operator std::normal_distribution<T>::operator()(Generator& g) is a non-const member function and thus cannot be called for a constant object. Just remove const from your function definition:

double operator()(const double & x, std::mt19937 &G) { return x + N(G); }

Also note that you most likely want to pass generator argument by reference