TProfile with error bars from file


I have a output file from a simulation with error values. This file has the x bins, the y value and RMS, resulting from the simulation. I created a script to convert this file to a TProfile because on the root manual said “Profile histograms are used to display the mean value of Y and its RMS for each bin in X. Profile histograms are in many cases an elegant replacement of two-dimensional histograms.”. But I don’t see the option on the TProfile to insert the error values from a file, only saw the weights. How can I put those error values in the TProfile?

This is one of the files:

[quote] # Results from PENCYL.

Energy distribution of transmitted photons.

1st column: E (eV).

2nd and 3rd columns: probability density and STU (1/(eV*particle)).

5.050000E+06 5.799000E-10 2.284469E-11
5.150000E+06 5.535000E-10 2.231866E-11
5.250000E+06 5.353000E-10 2.194867E-11
5.350000E+06 5.155000E-10 2.153894E-11
5.450000E+06 4.977000E-10 2.116383E-11
5.550000E+06 4.868000E-10 2.093081E-11
5.650000E+06 4.766000E-10 2.071037E-11
5.750000E+06 4.595000E-10 2.033546E-11
5.850000E+06 4.336000E-10 1.975406E-11
5.950000E+06 4.270000E-10 1.960315E-11
6.050000E+06 4.061000E-10 1.911740E-11
6.150000E+06 4.024000E-10 1.903012E-11
6.250000E+06 4.073000E-10 1.914563E-11
6.350000E+06 3.833000E-10 1.857301E-11
6.450000E+06 3.790000E-10 1.846854E-11
6.550000E+06 3.510000E-10 1.777326E-11
6.650000E+06 3.360000E-10 1.738936E-11
6.750000E+06 3.437000E-10 1.758748E-11
6.850000E+06 3.205000E-10 1.698354E-11
6.950000E+06 3.181000E-10 1.691984E-11
7.050000E+06 2.960000E-10 1.632152E-11
7.150000E+06 2.897000E-10 1.614690E-11
7.250000E+06 2.899000E-10 1.615247E-11
7.350000E+06 2.818000E-10 1.592523E-11
7.450000E+06 2.703000E-10 1.559690E-11
7.550000E+06 2.730000E-10 1.567461E-11
7.650000E+06 2.512000E-10 1.503577E-11
7.750000E+06 2.388000E-10 1.465998E-11
7.850000E+06 2.341000E-10 1.451499E-11
7.950000E+06 2.403000E-10 1.470594E-11
8.050000E+06 2.308000E-10 1.441233E-11
8.150000E+06 2.307000E-10 1.440921E-11
8.250000E+06 2.156000E-10 1.392967E-11
8.350000E+06 2.002000E-10 1.342298E-11
8.450000E+06 1.940000E-10 1.321350E-11
8.550000E+06 1.910000E-10 1.311094E-11
8.650000E+06 1.794000E-10 1.270658E-11
8.750000E+06 1.728000E-10 1.247066E-11
8.850000E+06 1.714000E-10 1.242004E-11
8.950000E+06 1.608000E-10 1.202987E-11
9.050000E+06 1.593000E-10 1.197363E-11
9.150000E+06 1.491000E-10 1.158395E-11
9.250000E+06 1.425000E-10 1.132467E-11
9.350000E+06 1.356000E-10 1.104710E-11
9.450000E+06 1.320000E-10 1.089947E-11
9.550000E+06 1.317000E-10 1.088708E-11
9.650000E+06 1.223000E-10 1.049136E-11
9.750000E+06 1.153000E-10 1.018670E-11
9.850000E+06 1.080000E-10 9.858953E-12
9.950000E+06 9.980000E-11 9.477294E-12
1.005000E+07 9.580000E-11 9.285428E-12
1.015000E+07 8.130000E-11 8.553912E-12
1.025000E+07 7.660000E-11 8.302980E-12
1.035000E+07 6.690000E-11 7.759484E-12
1.045000E+07 5.980000E-11 7.336190E-12
1.055000E+07 5.370000E-11 6.951959E-12
1.065000E+07 4.380000E-11 6.278521E-12
1.075000E+07 3.960000E-11 5.969913E-12
1.085000E+07 2.770000E-11 4.992988E-12
1.095000E+07 1.370000E-11 3.511408E-12[/quote]

And this is the script that I wrote:

[code]//This program must be inside the folder with the all the energy’s folders

char name[20], title[20], file_name[30];
ifstream read;
string line;
float x, y, rms, file=8.0;
int i, n;
TProfile *h;
TObjArray Hlist(0);

//open data files
for(i=0; i<=6; i++, file+=0.5){

//Check if data file is open and reports
  cout << "File ./" << file_name << " is open.\n";
cout << "Error opening " << file_name << ".\n";

//put stream pointer in the 6th line
for(n=1; n<=5; n++){
  getline (read,line);
  cout << "Stream pointer currently in line " << n << ".\n";
  cout << "Confirmation: " << line << "\n";

//write name and title of histogram
sprintf(name,"%.1f", file);
sprintf(title,"%.1f MeV", file);

//create histogram
h = new TProfile(name,title,60,5000000,11000000);

//get and write data lines
while( std::getline (read,line)){
  //read data from file
  istringstream(line,ios_base::in) >> x >> y >> rms;
  printf("Confirmation of data reading: x=%.2E; y=%.2E; rms=%.2E\n", x, y, rms);
  //Fill histogram with data from a line

//close the data files


TFile f(“histograms.root”,“RECREATE”,“Bremsstrahlung”);


why don’t you simply create a TH1D and call SetBinContent(y) and SetBinError(RMS)?

Cheers, Axel.

Thank Axel! It’s working now!

But I don’t get it, if it’s simpler to use error bars with TH1D, why do they say that TProfile histograms are better for RMS? I’m not gonna bother with TProfile anymore, but I’m just curious. :slight_smile: