//____________________________________________________________________
void fitCircle(Int_t n=10000) {
//generates n points around a circle and fit them
TCanvas *c1 = new TCanvas("c1","c1",600,600);
c1->SetGrid();
gr = new TGraph(n);
if (n> 999) gr->SetMarkerStyle(1);
else gr->SetMarkerStyle(3);
TRandom3 r;
Double_t x,y;
for (Int_t i=0;i<n;i++) {
r.Circle(x,y,r.Gaus(4,0.3));
gr->SetPoint(i,x,y);
}
c1->DrawFrame(-5,-5,5,5);
gr->Draw("p");
auto chi2Function = [&](const Double_t *par) {
//minimisation function computing the sum of squares of residuals
// looping at the graph points
Int_t np = gr->GetN();
Double_t f = 0;
Double_t *x = gr->GetX();
Double_t *y = gr->GetY();
for (Int_t i=0;i<np;i++) {
Double_t u = x[i] - par[0];
Double_t v = y[i] - par[1];
Double_t dr = par[2] - std::sqrt(u*u+v*v);
f += dr*dr;
}
return f;
};
// wrap chi2 funciton in a function object for the fit
// 3 is the number of fit parameters (size of array par)
ROOT::Math::Functor fcn(chi2Function,3);
ROOT::Fit::Fitter fitter;
double pStart[3] = {0,0,1};
fitter.SetFCN(fcn, pStart);
fitter.Config().ParSettings(0).SetName("x0");
fitter.Config().ParSettings(1).SetName("y0");
fitter.Config().ParSettings(2).SetName("R");
// do the fit
bool ok = fitter.FitFCN();
if (!ok) {
Error("line3Dfit","Line3D Fit failed");
}
const ROOT::Fit::FitResult & result = fitter.Result();
result.Print(std::cout);
//Draw the circle on top of the points
TArc *arc = new TArc(result.Parameter(0),result.Parameter(1),result.Parameter(2));
arc->SetLineColor(kRed);
arc->SetLineWidth(4);
arc->Draw();
}
//____________________________________________________________________
void fitCircle(Int_t n=10000) {
//generates n points around a circle and fit them
TCanvas *c1 = new TCanvas("c1","c1",600,600);
c1->SetGrid();
gr = new TGraph(n);
if (n> 999) gr->SetMarkerStyle(1);
else gr->SetMarkerStyle(3);
TRandom3 r;
Double_t x,y;
for (Int_t i=0;i<n;i++) {
r.Circle(x,y,r.Gaus(4,0.3));
gr->SetPoint(i,x,y);
}
c1->DrawFrame(-5,-5,5,5);
gr->Draw("p");
//Fit a circle to the graph points
TVirtualFitter::SetDefaultFitter("Minuit"); //default is Minuit
TVirtualFitter *fitter = TVirtualFitter::Fitter(0, 3);
fitter->SetFCN(myfcn);
fitter->SetParameter(0, "x0", 0, 0.1, 0,0);
fitter->SetParameter(1, "y0", 0, 0.1, 0,0);
fitter->SetParameter(2, "R", 1, 0.1, 0,0);
Double_t arglist[1] = {0};
fitter->ExecuteCommand("MIGRAD", arglist, 0);
//Draw the circle on top of the points
TArc *arc = new TArc(fitter->GetParameter(0),
fitter->GetParameter(1),fitter->GetParameter(2));
arc->SetLineColor(kRed);
arc->SetLineWidth(4);
arc->Draw();
}
void makegraph_xyhits_mchamp1000(){
//bool save_plots = false;
bool save_plots = true;
TCanvas* canvas = new TCanvas("c1","c1",10,10,700,550);
//canvas_style(canvas);
//TH2* h1=new TH2F("h1","",2000,0,2000,2000,-1000,1000);
TH2* h1=new TH2F("h1","",1000,-1000,0,1000,0,1000);
h1->SetStats(kFALSE);
h1->SetTitle(";x [cm];y [cm]");
//h2_style(h1,3,1,1,1001,50,-1111.,-1111.,510,510,20,1,1.4,0);
const Int_t n_hits = 20;
Float_t x[n_hits] = {-522.992,
-524.292,
-525.592,
-526.892,
-606.525,
-607.825,
-609.124,
-610.424,
-630.144,
-631.444,
-632.744,
-634.044,
-741.681,
-743.086,
-744.378,
-745.665,
-765.758,
-767.126,
-768.413,
-769.755};
Float_t y[n_hits] = {82.024,
82.388,
82.661,
82.971,
101.400,
101.678,
101.929,
102.318,
106.826,
107.214,
107.421,
107.769,
132.755,
132.924,
133.286,
133.657,
138.406,
138.637,
139.007,
139.285};
graph = new TGraph(n_hits, x, y);
//gr_style(graph,1,1,1,1001,50,-1111,-1111,510,510,20,1,1.3,1);
graph->SetMarkerStyle(20);
graph->SetMarkerSize(1);
graph->SetMarkerColor(1);
graph->SetTitle(";x [cm];y [cm]");
//graph->GetYaxis()->SetRangeUser(0,20);
//Fit a circle to the graph points
TVirtualFitter::SetDefaultFitter("Minuit"); //default is Minuit
TVirtualFitter *fitter = TVirtualFitter::Fitter(0, 3);
Int_t a,c;
Double_t b,f,par;
fitter->SetFCN(myfcn);
fitter->SetParameter(0, "x0", 0, 0.1, -1000, 1000);
fitter->SetParameter(1, "y0", 1000, 0.1, 0, 2000);
fitter->SetParameter(2, "R", 1000, 0.1, 0, 1000);
Double_t arglist[1] = {0};
fitter->ExecuteCommand("MIGRAD", arglist, 0);
//Draw the circle on top of the points
TArc *arc = new TArc(fitter->GetParameter(0),
fitter->GetParameter(1),fitter->GetParameter(2));
arc->SetLineColor(kRed);
arc->SetLineWidth(4);
Leg1 = new TLegend(0.45,0.75,0.75,0.85);
//Leg1->AddEntry(graph_noChaCut,"Average Before TS","p");
Leg1->AddEntry(graph,"After TS","p");
//Leg1->AddEntry(graph_predicted,"Predicted After TS","p");
Leg1->SetBorderSize(0);
Leg1->SetTextSize(0.04);
Leg1->SetFillColor(0);
//TPaveLabel *text1 = new TPaveLabel(.17,.85,.37,.89,"CMS Preliminary #sqrt{s}=8 TeV","NDC");
//TPaveLabel *text1 = new TPaveLabel(.17,.85,.37,.89,"CMS Preliminary #sqrt{s}=8 TeV 3.4 fb^{-1}","NDC");
//TPaveLabel *text1 = new TPaveLabel(.17,.85,.37,.89,"CMS Preliminary #sqrt{s}=8 TeV 4.4 fb^{-1}","NDC");
TPaveLabel *text1 = new TPaveLabel(.17,.85,.37,.89,"CMS Preliminary #sqrt{s}=8 TeV","NDC");
text1->SetBorderSize(0);
text1->SetTextSize(0.7);
text1->SetFillColor(0);
TPaveLabel *text2 = new TPaveLabel(.17,.85,.37,.89,"1000 GeV H++, Event 58654","NDC");
text2->SetBorderSize(0);
text2->SetTextSize(0.7);
text2->SetFillColor(0);
TPaveText* text1a = new TPaveText(-500,500,-300,700);
text1a->SetBorderSize(0);
text1a->SetTextSize(0.05);
text1a->SetFillColor(0);
double p0 = fitter->GetParameter(0);
double p1 = fitter->GetParameter(1);
double p2 = fitter->GetParameter(2);
double e0 = fitter->GetParError(0);
double e1 = fitter->GetParError(1);
double e2 = fitter->GetParError(2);
char p0name[50], p1name[50], p2name[50];
sprintf(p0name,"x0 = %.2f #pm %.2f",p0,e0);
sprintf(p1name,"y0 = %.2f #pm %.2f",p1,e1);
sprintf(p2name,"R = %.2f #pm %.2f",p2,e2);
text1a->AddText(p0name);
text1a->AddText(p1name);
text1a->AddText(p2name);
canvas->cd();
h1->Draw();
arc->Draw("same");
graph->Draw("Psame");
//text1->Draw();
text1a->Draw();
text2->Draw();
//Leg1->Draw();
if(save_plots) canvas->SaveAs("../plots/hits_xy_mchamp1000.eps");
//return 0;
}