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