Performance concern in GammaHandler::photoIonization

[kreczko]

Dear @Gratt55,

In the function GammaHandler::photoIonization is the first dimension of sourceInfo expected to be large (e.g. > 10)?

If yes, it might be worth changing

double GammaHandler::photoIonization(vector<vector<double>> sourceInfo, vector<double> xyTry) {
	//implement simple delta function to the spectrum
	double fValue = 0.0;
	for(int i = 0; i < sourceInfo.size(); i++) {
		double initialEnergy = sourceInfo[i][0];
		double br = sourceInfo[i][1];
		double pe = sourceInfo[i][2];
		double co = sourceInfo[i][3];
		double pp = sourceInfo[i][4];
		if(abs(xyTry[0]-initialEnergy) < brThresh) {
			fValue = yMax*br*(pe/(pe+co+pp));
		}
	}
	return fValue;
}

to

double GammaHandler::photoIonization(const vector<vector<double>>& sourceInfo, 
     const vector<double>& xyTry) {
	//implement simple delta function to the spectrum
	double value {0.0};
        std::size_t index {0};
	for(int i = 0; i < sourceInfo.size(); i++) {
	  double initialEnergy {sourceInfo[i][0]};
          if(abs(xyTry[0] - initialEnergy) < brThresh) {
            index = i;
	  }
	}
        double br = sourceInfo[index][1];
	double pe = sourceInfo[index][2];
	double co = sourceInfo[index][3];
	double pp = sourceInfo[index][4];
        value = yMax * br * ( pe / (pe + co + pp) );
	return value;
}

(also changed fValue → value as f<Name> is usually the notation for class members, not local variables).