| Geant4 Cross Reference |
1 // ******************************************* 1
2 // To execute this macro under ROOT after your
3 // 1 - launch ROOT (usually type 'root' at y
4 // 2 - type '.X spectrum.C' at the ROOT sess
5 // 3 - OR type directly 'root spectrum.C'
6 // this will generate an output energy spectru
7 // according to selected statistics and distri
8 // (energy unit assumed by svalue example: eV)
9 // *******************************************
10
11 {
12 gROOT->Reset();
13
14 // 1) SELECT number of values to shoot
15 int nbValues = 100;
16 //
17
18 double value;
19 TNtuple * ntuple = new TNtuple ("","","value")
20
21 FILE * fp = fopen("spectrum.txt","w");
22
23 TRandom r;
24
25 for (int i=0;i<nbValues;i++)
26 {
27 // 2) SELECT distribution
28 // here Gaussian with mean, sigma
29 // see https://root.cern.ch/doc/master/clas
30 value = r.Gaus(1.,0.1);
31 //
32 ntuple->Fill(value);
33 fprintf(fp,"%f \n",value);
34 }
35 fclose(fp);
36
37 ntuple->Draw("value");
38 }
39