#include "TH1.h"
#include "TF1.h"
#include "TFile.h"
#include "TCanvas.h"
#include "TGInputDialog.h"
#include "Riostream.h"

//Attempt at a fit function - x, y and z and are intended to stand in for the values in the arrays X0[i], X2[i] and X4[i]
// par[0]=G2 and par[1]=G4
        Double_t Gks(Double_t *x, Double_t *y, Double_t *z, Double_t *par) { 
	const int n = 20; 
	Double_t x[n]; 
	Double_t y[n]; 
	Double_t z[n]; 
	return x[0]+par[0]*y[0]+par[1]*z[0];
} 


 void test() {
	Double_t G2 = 0.63;  //reasonable starting value for G2
	Double_t G4 = 0.42;  //reasonable starting value for G4
	TFile* file = TFile::Open( "Ru960309_PhiCanvas.root", "READ" );
	PhiCanvas->Draw();
	TFile *f = new TFile("Ru960309.root","RECREATE");
	TH1F *h1 = new TH1F("h1","Xk values",5,1,5);
	TTree *TREE = new TTree("TREE","heliofit data from ascii file");
	Long64_t nlines = TREE->ReadFile("Ru960309.txt","theta:det_no:X0:X2:X4");  //read the ASCII file that contains the array values
	printf(" found %lld points\n",nlines);
	PhiCanvas->cd(1);
	hTheta90->SetLineWidth(1.0); 
	hTheta90->SetStats(1); 
	hTheta90->SetLineStyle(1); 
	hTheta90->SetLineColor(kBlue); 
	hTheta90->Draw("PCE1");
	TREE->SetLineWidth(1.0); 
	TREE->SetLineStyle(2); 
	TREE->SetLineColor(kBlack); 	
	//Examples of the type of fit I am hoping to achieve
	TREE->Draw("X0+0.86*X2+0.64*X4:(det_no-1)*45","theta==90","same PC"); 
	TREE->Draw("X0+0.75*X2+0.53*X4:(det_no-1)*45","theta==90","same PC");
	TREE->Draw("X0+0.63*X2+0.42*X4:(det_no-1)*45","theta==90","same PC");
	TREE->Draw("X0+0.52*X2+0.31*X4:(det_no-1)*45","theta==90","same PC");
	TREE->Draw("X0+0.41*X2+0.20*X4:(det_no-1)*45","theta==90","same PC");
	TF1 *Gks = new TF1("Gks",Gks,180,1,180);
	hTheta90->Fit("Gks");
	Gks->SetParNames("G2","G4");
	Gks->SetParameters(G2,G4);
	Gks->SetParLimits(0,0,1);
	Gks->SetParLimits(1,0,1);
	Gks->SetLineWidth(5.0); 
	Gks->SetLineStyle(1); 
	Gks->SetLineColor(kBlue); 
	Gks->Draw("same");  

}