I have 1D histo. I have derived it from ROOT file. So, I need to create cumulative histo from my 1D histo. As I have correlation errors in each bin of my 1D histo I need to create covariance matrix for cumulative histo fitting. For this reason I had to use TMinuit.
I have created my fit model pol7_model. I have created fcn function for calculation chi square value.
So in my script, when I call minimization->mnexcm, I recieve error :
Error: illegal pointer to class object histo_cum 0x0 204 script_matr.C:36:
histo_cum is cumulative histo which have already defined. I don’t understand why it can be.