double exact_exchange(int func_id) {
// Default - no exact exchange.
double f=0.0;
if(func_id>0) {
xc_func_type func;
if(xc_func_init(&func, func_id, XC_UNPOLARIZED) != 0){
ERROR_INFO();
std::ostringstream oss;
oss << "Functional "<<func_id<<" not found!";
throw std::runtime_error(oss.str());
}
switch(func.info->family)
{
case XC_FAMILY_HYB_GGA:
case XC_FAMILY_HYB_MGGA:
// libxc prior to 2.0.0
// f=xc_hyb_gga_exx_coef(func.gga);
// libxc 2.0.0
f=xc_hyb_exx_coef(&func);
break;
}
xc_func_end(&func);
}
// printf("Fraction of exact exchange is %f.\n",f);
return f;
}
double VXChybrid_coeff(int xc_id, int spin)
{
xc_func_type func;
double factor;
if(xc_func_init(&func, xc_id, spin) != 0){
fprintf(stderr, "XC functional %d not found\n", xc_id);
exit(1);
}
switch(func.info->family)
{
case XC_FAMILY_HYB_GGA:
case XC_FAMILY_HYB_MGGA:
factor = xc_hyb_exx_coef(&func);
break;
default:
factor = 0;
}
xc_func_end(&func);
return factor;
}
DFTFunctional(int FUNC_IDENT) {
xc_func_init(&functional_,FUNC_IDENT,XC_POLARIZED);
xHFX = xc_hyb_exx_coef(&functional_);
//std::cerr << "HYB " << xHFX << std::endl;
};
