Hi!
I need to fit a histogram with a complicated function: a gaussian convoluted with a landau and rescaled.
I used the function langaufun that is defined in the source file langaus.C. here is the code:
…
TF1* langaussi= new TF1(“langaussi”,langaufun,394,404,4);
langaussi->SetParameter(0,0.2);
langaussi->SetParameter(1,397.5);
langaussi->SetParameter(2,1000);
langaussi->SetParameter(3,0.05);
langaussi->SetParNames(“a”,“b”,“c”,“d”);
TF1* scale= new TF1(“scale”,"[0]pow(x,-3)",394,404);
scale->SetParameter(0,5TMath::Power(10,-12));
scale->SetParNames(“e”);
TF1* TOT= new TF1(“TOT”, “langaufun * scale”,394,404);
TOT->SetParameter(0,0.2);
TOT->SetParameter(1,397.5);
TOT->SetParameter(2,1000);
TOT->SetParameter(3,0.03);
TOT->SetParameter(4,10^(-12));
TOT->SetParNames(“Lwidth”,“LMpv”,“Area”,“GsSigma”,“scala”);
…
With the two functions langaussi and scale I have no problems: I can draw them and change their parameters, but when I define the function TOT I have this error message:
Error in TFormula::Compile: Bad numerical expression : "langaufun"
Error in TF1::TF1: function: TOT/langaufun * scale has 0 parameters instead of 1
It seems I cannot call the first function by name, but it is impossible to write it in formula… I read the TF1 documentation but I still cannot find what’s wrong in the code
Can someone help me please?