Plotting only one point on canvass

Newbie
1

hi everyone :slight_smile: i would have wanted to print only just one point on a canvass.
kindly, see part of the code.

//=== generating the functions ===//
 for (Int_t i=0; i<nof; i++)
 {
  fna = "f"; fna += i;
  fpf[i] = new TF1("fna","(((2.0*[0]*[0]*[1]*[1]*[2]*[2]*[3]*[3])/(x*x*sin([4]*[5]/360.0)*sin([4]*[5]/360.0)*sin([4]*[5]/360.0)*sin([4]*[5]/360.0)+2.0*[3]*[3]*x*sin([4]*[5]/360.0)*sin([4]*[5]/360.0)+(x*sin([4]*[5]/360.0)*sin([4]*[5]/360.0)*sqrt(x*x*sin([4]*[5]/360.0)*sin([4]*[5]/360.0)*sin([4]*[5]/360.0)*sin([4]*[5]/360.0)+4.0*[3]*[3]*x*sin([4]*[5]/360.0)*sin([4]*[5]/360.0)))))*((2.0*[3]*[3])/(2.0*[3]*[3]+x*sin([4]*[5]/360.0)*sin([4]*[5]/360.0)+sqrt(x*x*sin([4]*[5]/360.0)*sin([4]*[5]/360.0)*sin([4]*[5]/360.0)*sin([4]*[5]/360.0)+4.0*[3]*[3]*x*sin([4]*[5]/360.0)*sin([4]*[5]/360.0))))*((4.0*[3]*[3])/(4.0*[3]*[3]+x))*(((0.71)/(0.71+x))*((0.71)/(0.71+x))*((0.71)/(0.71+x))*((0.71)/(0.71+x))*([7]*[7]*[8]*[8]*cos([4]*[5]/360.0)*cos([4]*[5]/360.0)+[6]*[6]*[7]*[7]*(2.0*[3]*[3]*x*cos([4]*[5]/360.0)*cos([4]*[5]/360.0)+4.0*[3]*[3]*x*sin([4]*[5]/360.0)*sin([4]*[5]/360.0)+x*x*sin([4]*[5]/360.0)*sin([4]*[5]/360.0))/(8.0*[3]*[3]*[3]*[3]))))", 0.0025, 1.0);
  fpf[i]->SetParameter(0,1.0);
  fpf[i]->SetParameter(1,1.0);
  fpf[i]->SetParameter(2,1.0/137.0);
  fpf[i]->SetParameter(3,gRandom->Gaus(0.938272081,0.000000006));
  fpf[i]->SetParameter(4,27.0);
  fpf[i]->SetParameter(5,TMath::Pi());
  fpf[i]->SetParameter(6,2.792847351);
  fpf[i]->SetParameter(7,gRandom->Gaus(0.979,0.022)+gRandom->Gaus(0.0,0.010));
  fpf[i]->SetParameter(8,gRandom->Gaus(0.914,0.024)+gRandom->Gaus(0.0,0.010));
 }

 Int_t nop=300;

 Double_t xpt, ypt, del = 0.9975/nop;

 auto av1 = new TGraph(nop);
 //TGraph *av1 = new TGraph();
 for (Int_t j=0; j < nop; j++)
 {
  xpt = del*j + 0.0025*del;
  av1->SetPoint(j, xpt, 0.0);
 }
 for (Int_t i=0; i<nof; i++)
 {
  for (Int_t j=0; j < nop; j++)
  {
   av1->GetPoint(j, xpt, ypt);
   av1->SetPoint(j, xpt, ypt + fpf[i]->Eval(xpt)/(Double_t)nof);
  }
 }

 av1->SetMarkerStyle(7);
 av1->SetMarkerColor(kGreen);
 av1->SetMarkerSize(1);

//=== Plotting the point on canvas ===//
int j = 0;

TGraph *av0000 = new TGraph();
double q20 = 0.399008;
double eps = 0.01;

 for (Int_t i=0; i<nof; i++)
 {
   av1->GetPoint(i, xpt, ypt);
   if ( abs(xpt - q20) < eps)
   {
    av0000->GetPoint(i, xpt, ypt);
    av0000->SetPoint(j, xpt, ypt + fpf[i]->Eval(xpt)/(Double_t)nof);
    j++;
   }
 }

 av0000->SetMarkerStyle(22);
 av0000->SetMarkerColor(3); //green
 av0000->SetMarkerSize(1);

TMultiGraph *mgp = new TMultiGraph();
 mgp->SetTitle("dcs of ep, eq_s, eq_c (with mrf); Transfer Momentum in GeV^2; Differential Cross Section");
 mgp->SetMinimum(1.e-5);
 mgp->SetMaximum(1.e0);
 mgp->Add(av0000,"*");

but I get a curve of points.

Screenshot%20from%202019-11-06%2021-26-11
Screenshot from 2019-11-06 21-26-11.png1920Ă—1080 69.3 KB

2

In the code you posted we do not see the drawing part.

3

is this what you mean?:

TMultiGraph *mgp = new TMultiGraph();
 mgp->SetTitle("dcs of ep, eq_s, eq_c (with mrf); Transfer Momentum in GeV^2; Differential Cross Section");
 mgp->SetMinimum(1.e-5);
 mgp->SetMaximum(1.e0);
 mgp->Add(av0000,"*");
4

Well … It would be better to see the whole macro… But: if you put in a multigraph several graphs having several points how can you see only one point ?

5

i will send the macro in the email… each graph should only contain one point in this case :slight_smile:

6

Please send working code. I get:

Processing TheMacro.C...
In file included from input_line_9:1:
/Users/couet/Downloads/TheMacro.C:1458:17: error: invalid suffix '.498758' on floating constant
double q21 = 0.0.498758;

Also, no need to send the code by private email. post it here as attachement.

7

gracias… okay, I will
DataPoints.C (95.1 KB)

8

Your macro gives me this plot. What is wrong with it ?

13
Screenshot 2019-11-08 at 17.05.13.jpg1954Ă—1928 225 KB

9

I think you always need:

TGraph *av... = new TGraph();
j = 0; // "reset" it
10

Basically your macro does:

 mgp->Add(av0000,"PL");
 mgp->Draw("a");

av0000 has 3 points…we see 3 points … all is fine .

11

i see… i will tweak it again… gracias :slight_smile:

12

could it be the version of ROOT?
5-34-32
5-34-34
5-34-36

13

unrelated question:
How do I store the output text in to a file?
I mean, the command to do it?

regards,
jaybee

14

cplusplus.com -> Tutorials -> C++ Language -> Input/output with files

15

If you want to use ROOT 5, you need to get rid of all c++11 and newer statements in your macro (e.g. “auto”).

16

I could not anymore recognize which are C++ statements in the code but I have commented all the “auto” codeDataPointStatNewEPEQDCSProbColorWithMRF02.C (95.2 KB) . But the output is still the same :slight_smile:

17

I get the same plot as @couet with ROOT 5.34/36.

You can add:

#include "TCanvas.h"
#include "TPad.h"
#include "TStyle.h"
#include "TH1.h"
#include "TF1.h"
#include "TString.h"
#include "TRandom3.h"
#include "TGraph.h"
#include "TMultiGraph.h"
#include "TMath.h"

and then try:
root [0] .x DataPointStatNewEPEQDCSProbColorWithMRF02.C++

Note: an unused variable “av0002”: TGraph *av0002 = new TGraph();

BTW. in order to simplify your code (you can get rid of “j”), you can use:
av...->SetPoint(av...->GetN(), xpt, ypt + ...); // append a new point

18

okay… muchas gracias… i will implement your suggestions :slight_smile:

19

yeah… it worked… gracias :slight_smile:

20

do i need to put the data point number in …-GetN(241) [for example]…