MaterialData MaterialManager::createAveragedMaterial( const MaterialVec& materials ) {
std::stringstream sstr ;
double sum_l = 0 ;
double sum_rho_l = 0 ;
double sum_rho_l_over_A = 0 ;
double sum_rho_l_Z_over_A = 0 ;
//double sum_rho_l_over_x = 0 ;
double sum_l_over_x = 0 ;
//double sum_rho_l_over_lambda = 0 ;
double sum_l_over_lambda = 0 ;
for(unsigned i=0,n=materials.size(); i<n ; ++i){
Material mat = materials[i].first ;
double l = materials[i].second ;
if( i != 0 ) sstr << "_" ;
sstr << mat.name() << "_" << l ;
double rho = mat.density() ;
double A = mat.A() ;
double Z = mat.Z() ;
double x = mat.radLength() ;
double lambda = mat.intLength() ;
sum_l += l ;
sum_rho_l += rho * l ;
sum_rho_l_over_A += rho * l / A ;
sum_rho_l_Z_over_A += rho * l * Z / A ;
sum_l_over_x += l / x ;
sum_l_over_lambda += l / lambda ;
// sum_rho_l_over_x += rho * l / x ;
// sum_rho_l_over_lambda += rho * l / lambda ;
}
double rho = sum_rho_l / sum_l ;
double A = sum_rho_l / sum_rho_l_over_A ;
double Z = sum_rho_l_Z_over_A / sum_rho_l_over_A ;
// radiation and interaction lengths already given in cm - average by length
// double x = sum_rho_l / sum_rho_l_over_x ;
double x = sum_l / sum_l_over_x ;
// double lambda = sum_rho_l / sum_rho_l_over_lambda ;
double lambda = sum_l / sum_l_over_lambda ;
return MaterialData( sstr.str() , Z, A, rho, x, lambda ) ;
}
