I am trying to do the following fit:
TGraphErrors g(fitLength,z,absx,zerr,xerr);
TCanvas cd("cd","",0,0,500,500);
g.Draw("A*");
g.Fit("pol2","Q");
I am running this over a large number of events. In some cases, I have:
z[0] = z[1] =........=z[6]
when the fit is done over these arrays, i get the following error message:
Error in <TDecompChol::Decompose()>: matrix not positive definite
Error in <TDecompChol::Solve()>: Decomposition failed
is there a root function I can use which will help me skip the fitting step if a case like the above occurs ?
-thanks debdatta.