was not declared in this scope

[ozae]

hi i have been working and get stuck with something like this"
C:\Users\ThinkPad\Desktop\2D\HEL\main.cpp|225|error: 'set' was not declared in this scope, and no declarations were found by argument-dependent lookup at the point of instantiation [-fpermissive]|"
here is the portion of mycode
template<class T, int N, int M> class matrix : public vector<vector<T,N>,M>{
public:
matrix(){}
matrix(const vector<vector<T,N>,M>&){}
matrix(double d){
this->set(0,point(d,0.));
this->set(1,point(0.,d));
} // constructor
matrix(const vector<T,N>&u, const vector<T,N>&v){
set(0,u);
set(1,v);
} // constructor
matrix(const vector<T,N>&u, const vector<T,N>&v, const vector<T,N>&w){
set(0,u);
set(1,v);
set(2,w);
} // constructor
~matrix(){} // destructor
const T& operator()(int i,int j) const{return (*this)[j][i];}//A(i,j)
const matrix& operator+=(const matrix&);
const matrix& operator-=(const matrix&);
const matrix& operator*=(const T&);
const matrix& operator/=(const T&);
};

[Duthomhas]

It means that you are trying to use a function/method that does not exist: your matrix class does not define it and the std::vector class does not define it. You must add a set() method to your matrix class.