mean11 = RooRealVar("mean11","mean of gaussian",2,-10,10) sigma11 = RooRealVar("sigma11","width of gaussian",3,0.1,10) gauss11 = RooGaussian("gauss11","gaussian PDF",x ,mean11 ,sigma11) # fit partial range #gauss11.fitTo(data3_half,RooFit.Range("left_gaussian_range")) # convert to ext PDF then fit nGauss11 = RooRealVar("nGauss11", "Gauss 11 ext pdf",750 , 0., 2000) gauss11_ext = RooExtendPdf("gauss11_ext", "extended p.d.f", gauss11, nGauss11) #gauss11_ext.plotOn(xframe7,RooFit.Normalization( nGauss11.getVal() , RooAbsReal.NumEvent), RooFit.Range("left_gaussian_range"), RooFit.LineColor(RooFit.kRed)) #gauss11_ext.plotOn(xframe7,RooFit.Normalization( nGauss11.getVal() , RooAbsReal.NumEvent), RooFit.Range("whole_range"), RooFit.LineColor(RooFit.kRed)) gauss11_ext.fixAddCoefRange("whole_range") gauss11_ext.fitTo(data3_half,RooFit.Range("left_gaussian_range")) print "" print "mean11: ", mean11.Print(), print "" print "sigma11: ", sigma11.Print() print "" print "nGauss11: ", nGauss11.Print() print "" # plot #gauss10.plotOn(xframe7, RooFit.Normalization( data3.sumEntries() , RooAbsReal.NumEvent) ) #gauss10.plotOn(xframe7, RooFit.Normalization( data3.sumEntries() , RooAbsReal.NumEvent) , RooFit.Range("left_gaussian_range")) gauss10.plotOn(xframe7, RooFit.Normalization( 500 , RooAbsReal.NumEvent) , RooFit.Range("left_gaussian_range"))