[Help-gsl] Segfault in gsl_integration_qag

[Thomas Markovich]

Hi,

I have been racking my brain over this segmentation fault for a few  
days now and tracked it down to gsl_integration_qag. The strange thing  
is that the segmentation fault only happens after n and m =  37. I did  
try increasing the size of my work space but that didn't seem to do  
much of anything at all. Any suggestions? I'm sure the error is  
something thats obvious to someone more experienced with the gsl.

I have included the code below:

        int N = 50; //Starting size
        double sum = 0.0;
        int j = 0;
        int sizeN = 2*N+1; //Size
        mat HN(sizeN,sizeN); //Defines the hamiltonian matrix
	gsl_integration_workspace * w = gsl_integration_workspace_alloc  
(100000);
        double result1,result2, error;
        gsl_function F1;
        struct my_f_params alpha = {2,2};               
        F1.function = &f1;
        F1.params = α
        for(int n = 0; n <= sizeN; n++)
        for(int m = 0; m <= sizeN; m++)
        {
                        alpha.a = n;
                        alpha.b = m;
			gsl_integration_qag (&F1, 0, 6, 0, 1e-4, 1000, GSL_INTEG_GAUSS61,w,  
&result1, &error);
			gsl_integration_qag (&F1, -6, 0, 0, 1e-4, 1000,  
GSL_INTEG_GAUSS61,w, &result2, &error);
                        cout << m << "  " << n << endl;
                        HN(n,m) = result1 + result2;
        }

with f1 being

double f1 (double x, void * p) { //Deriviative part of the integral
        struct my_f_params * params = (struct my_f_params *)p;
        int n = (params->a);
        int m = (params->b);
	double f = exp(-(x*x))*hermitecalculate(m,x)*( (-1.0)*((4*n*n -  
4*n)*hermitecalculate(n-2,x) - 4*n*hermitecalculate(n-1,x)*x -  
hermitecalculate(n,x) + hermitecalculate(n,x)*x*x));
	f += exp(-x*x)*hermitecalculate(n,x)*hermitecalculate(m,x)*(pow(x, 
6.0) + 4*pow(x,4) + x*x - 2);
	return f/ 
(sqrt 
(gsl_sf_fact 
(n)*sqrt(pi)*pow(2.0,n))*sqrt(gsl_sf_fact(m)*sqrt(pi)*pow(2.0,m)));
}

and my_f_params defined as

struct my_f_params {int a; int b;};