S H I N E

Friday, August 2, 2024

GSL interpolation

#include 
#include 
#include 


 double INTERPOLATE1D( double logx,const vector& logx0, const vector& logy0)
 {
     const gsl_interp_type *T = gsl_interp_cspline;//gsl_interp_linear;
     gsl_spline *s = gsl_spline_alloc(T,logx0.size());
     gsl_interp_accel *acc = gsl_interp_accel_alloc();
     gsl_spline_init(s,&logx0[0],&logy0[0],logx0.size());
 
     double logy = gsl_spline_eval(s,logx,acc);
     gsl_spline_free(s);
     gsl_interp_accel_free(acc);
     return pow(10,logy);
 }

Thursday, August 1, 2024

pass parameters in GSL integration

struct my_f_params {int a; int b;}; 
gsl_function F1; 
struct my_f_params alpha = {2,2};               
F1.function = &f1; 
F1.params = & alpha;

struct my_f_params * params = (struct my_f_params *)p;
int n = (params->a);
int m = (params->b);

----------

double params[] = { y, z };
F.params = params;

double y = ((double *)params)[0];
double z =  *((double *)p+1);