add tutorial for illustrating ROOT::Math statistical functions in the case of...

add tutorial for illustrating ROOT::Math statistical functions  in the case of the normal distribution


git-svn-id: http://root.cern.ch/svn/root/trunk@17194 27541ba8-7e3a-0410-8455-c3a389f83636

tutorials/math/normalDist.C

+// tutorial illustrating the various distributions available in 
+// MathCore and MathMore
+
+#ifndef __CINT__
+#include "Math/DistFunc.h"
+#include "TF1.h"
+#include "TCanvas.h"
+#include "TSystem.h"
+#include "TLegend.h"
+#include "TAxis.h"
+#endif
+
+
+
+void normalDist() { 
+
+#ifdef __CINT__
+   gSystem->Load("libMathCore");
+   gSystem->Load("libMathMore");
+#endif
+
+   TF1 *pdfunc  = new TF1("pdf","ROOT::Math::normal_pdf(x, [0],[1])",-5,5);
+   TF1 *cdfunc  = new TF1("cdf","ROOT::Math::normal_cdf(x, [0],[1])",-5,5);
+   TF1 *ccdfunc = new TF1("cdf_c","ROOT::Math::normal_cdf_c(x, [0])",-5,5);
+   TF1 *qfunc   = new TF1("quantile","ROOT::Math::normal_quantile(x, [0])",0,1);
+   TF1 *cqfunc  = new TF1("quantile_c","ROOT::Math::normal_quantile_c(x, [0])",0,1);
+
+   pdfunc->SetParameters(1.0,0.0);  // set sigma to 1 and mean to zero
+   pdfunc->SetTitle("");
+   pdfunc->SetLineColor(kBlue);
+
+   pdfunc->GetXaxis()->SetLabelSize(0.06);
+   pdfunc->GetXaxis()->SetTitle("x");
+   pdfunc->GetXaxis()->SetTitleSize(0.07);
+   pdfunc->GetXaxis()->SetTitleOffset(0.55);
+   pdfunc->GetYaxis()->SetLabelSize(0.06);
+ 
+
+
+
+
+   cdfunc->SetParameters(1.0,0.0);  // set sigma to 1 and mean to zero
+   cdfunc->SetTitle("");
+   cdfunc->SetLineColor(kRed);
+
+   cdfunc->GetXaxis()->SetLabelSize(0.06);
+   cdfunc->GetXaxis()->SetTitle("x");
+   cdfunc->GetXaxis()->SetTitleSize(0.07);
+   cdfunc->GetXaxis()->SetTitleOffset(0.55);
+   
+   cdfunc->GetYaxis()->SetLabelSize(0.06);
+   cdfunc->GetYaxis()->SetTitle("p");
+   cdfunc->GetYaxis()->SetTitleSize(0.07);
+   cdfunc->GetYaxis()->SetTitleOffset(0.55);
+ 
+   ccdfunc->SetParameters(1.0,0.0);  // set sigma to 1 and mean to zero
+   ccdfunc->SetTitle("");
+   ccdfunc->SetLineColor(kGreen);
+
+   qfunc->SetParameter(0, 1.0);  // set sigma to 1 
+   qfunc->SetTitle("");
+   qfunc->SetLineColor(kRed);
+   qfunc->SetNpx(1000); // to get more precision for p close to 0 or 1
+
+   qfunc->GetXaxis()->SetLabelSize(0.06);
+   qfunc->GetXaxis()->SetTitle("p");
+   qfunc->GetYaxis()->SetLabelSize(0.06);
+   qfunc->GetXaxis()->SetTitleSize(0.07);
+   qfunc->GetXaxis()->SetTitleOffset(0.55);
+   qfunc->GetYaxis()->SetTitle("x");
+   qfunc->GetYaxis()->SetTitleSize(0.07);
+   qfunc->GetYaxis()->SetTitleOffset(0.55);
+
+   cqfunc->SetParameter(0, 1.0);  // set sigma to 1 
+   cqfunc->SetTitle("");
+   cqfunc->SetLineColor(kGreen);
+   cqfunc->SetNpx(1000); 
+   
+
+   TCanvas * c1 = new TCanvas("c1","Normal Distributions",100,10,600,800);
+
+   c1->Divide(1,3);
+   c1->cd(1);
+
+   pdfunc->Draw();
+   TLegend *legend1 = new TLegend(0.583893,0.601973,0.885221,0.854151);
+   legend1->AddEntry(pdfunc,"normal_pdf","l");
+   legend1->Draw();
+
+   c1->cd(2);
+   cdfunc->Draw();
+   ccdfunc->Draw("same");
+   TLegend *legend2 = new TLegend(0.585605,0.462794,0.886933,0.710837);
+   legend2->AddEntry(cdfunc,"normal_cdf","l");
+   legend2->AddEntry(ccdfunc,"normal_cdf_c","l");
+   legend2->Draw();
+
+   c1->cd(3);
+   qfunc->Draw();
+   cqfunc->Draw("same");
+   TLegend *legend3 = new TLegend(0.315094,0.633668,0.695179,0.881711);
+   legend3->AddEntry(qfunc,"normal_quantile","l");
+   legend3->AddEntry(cqfunc,"normal_quantile_c","l");
+   legend3->Draw();
+
+
+   
+}