TF1 definition using a class member

ROOT
1

I would like to perform a numeral integration and define my function wrapped in classes. How can I do it? I enclosed the macro eluminating the scheme I would like to use but it doesn’t work.

Jan
P.S. I know there is a mathmore stuff, but it doesn’t solve my probelm.

const int GLN=100;
double glx[GLN],glw[GLN];

struct MyIntegClass{

MyIntegClass() {
    mypar=2.0;
    fFunc = new TF1("fFunc",F_func,0,10);
    fFunc->CalcGaussLegendreSamplingPoints(GLN,glx,glw);
}

double F_func(double *x, double *par){
    return mypar*x[0];
}


double operator() (double *x, double * ) const { 
    //return fFunc->Derivative(*x);
    return fFunc->Eval(*x);
}

double Eval(double par) {
    mypar=par;
    return fFunc->IntegralFast(GLN,glx,glw, 0, 1);
}

TF1 * fFunc; 
double mypar;

};

void myInteg(){

MyIntegClass *myinteg = new MyIntegClass();

TF1 * f2 = new TF1("f2",myinteg, -10, 10, 0, "MyIntegClass"); 
f2->Draw();

cout<<"Integral = "<< myinteg->Eval(5) <<endl;

}

2

Hi,

For now, you need to write a free standing function that wraps the call to the object function.

Cheers,
Philippe

3

For example you could have[code]MyIntegClass *myinteg = 0;
double my_wrapper(double *x, double *par)
{
return (*myinteg)(x,par);
};

void myInteg(){

myinteg = new MyIntegClass();

TF1 * f2 = new TF1(“f2”,myinteg, -10, 10, 0, “MyIntegClass”);
f2->Draw();

cout<<"Integral = "<< myinteg->Eval(5) <<endl;

}[/code]

Cheers,
Philippe