findMinChi2.C

//#include "/star/u/syang/Macro/headers.h"
//#include "/star/u/syang/Macro/function.C"

//find the minimum Chi2 among all the root files, then print out the root file full name
//the name of the root file  will tell what parameter settings give the minimum chi2

void findMinChi2(const Char_t* inputFileList = "minChi2_file.list")
{
        ifstream fin(inputFileList);
        if(!fin){
                Error("Error, inputfile", "can't open %s", inputFileList);
                return;
        }

        Double_t minChi2 = 1.e9;
        TString minName  = "";

        ofstream outData("minChi2_rootfile_fullname.dat");

        TString name("");

        while( fin >> name )
        {
                TFile* file = TFile::Open(name);
                if(!file || !file->IsOpen() || !file->GetNkeys())
                {
                        Error("check chi2", "can't open %s", name.Data());
                        continue;
                }
                //cout << "OPEN " << file->GetName() << endl;

                TH3* hchi2 = (TH3D*) file->Get("hChi2");

                for(Int_t i=0; i<hchi2->GetNbinsX(); i++)//parameter n_{pp}
                {
                        for(Int_t j=0; j<hchi2->GetNbinsY(); j++)//parameter k
                        {
                                for(Int_t k=0; k<hchi2->GetNbinsZ(); k++)//parameter x
                                {
                                        Double_t chi2 = hchi2->GetBinContent(i+1, j+1, k+1);

                                        if(chi2<minChi2)
                                        {
                                                minChi2 = chi2;
                                                minName = name;
                                                
                                                //if(minChi2<10) 
                                                //{
                                                //      outData<<"minChi2: "<<minChi2<<"    fileName: "<<minName<<endl;
                                                //      cout<<"minChi2: "<<minChi2<<"    fileName: "<<minName<<endl;
                                                //}
                                        }
                                }
                        }
                }

                file->Close();
        }
        
        outData<<"The minimum Chi2 are found: "<<minChi2<<endl;
        outData<<"the corresponding root fileName: "<<endl;
        outData<<minName<<endl;
        outData.close();

        cout<<endl;
        cout<<"The minimum Chi2: "<<minChi2<<"    fileName: "<<minName<<endl;
}