in roofit, pdfs should be always normalised to unity, however if I plot simple pdfs they are always normalized to different values, is this a “feature”? (For example, even the two gaussians at page 8 of the roofit manual v2.91 are normalised to 0.2.)
I suppose (as stated in the manual) that each pdf is normalised in the given variable range.
For example if I plot a polynomial and a gaussian with:
RooRealVar x("x", "x", 0, -1., 1.); RooRealVar a("a", "a", 0.1); RooPolynomial pol("pol", "pol",x, RooArgSet(a)); RooGaussian gauss("gauss","gauss",x, RooFit::RooConst(0),RooFit::RooConst(1)); RooPlot *xframe = x.frame(); pol.plotOn(xframe); gauss.plotOn(xframe); xframe->Draw();
I get the plot in attachment, which shows that the normalisation is clearly 0.02.
What am I missing? Perhaps a hidden “bin width”?
Note: I tried this on different computers and different root versions.
The current version in my pc is: 5.29/01