Hi,
I got an error when using TGraph::Fit().the error message is the
following:
-------------------------------
signal SEGV (no mapping at the fault address) in TGraph::Fit at line 676
in file "G_Graph.cxx"
676 if (!Foption.Plus) fFunctions->Delete();
(dbx) print fFunctions
fFunctions = (nil)
----------------------------------
It seems that fFunctions points to nothing.
To reproduce the error, try to run the following macro:
fittest (){
TF1 *myfit = new TF1("myfit","[0]*sin(x) + [1]*exp(-[2]*x)", 0, 2);
myfit->SetParName(0,"c0");
myfit->SetParName(1,"c1");
myfit->SetParName(2,"slope");
myfit->SetParameter(0, 1);
myfit->SetParameter(1, 0.05);
myfit->SetParameter(2, 0.2);
TGraph *gr=new TGraph;
gr->SetPoint(1,0.4,0.45);
gr->SetPoint(2,0.8,0.74);
gr->SetPoint(3,1.2,0.97);
gr->SetPoint(4,1.6,1.035);
gr->SetPoint(5,1.4,1.02);
gr->Fit("myfit","R");
}
Is there any solution for this ?
I will appreciate any help. Thanks.
Best Regards.
Aihong
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