Setting titles for TGraphs

ROOT
1

Hello. I need to do a very simple task

..........
TGraph *graph = new TGraph(point, x,y);
graph->SetTitle("some title");
graph->GetYaxis()->SetTitle("some title01");  // this does not appaer in my graph
.........
graph->Draw("AL*");
return graph;

Did I miss anything, in the Draw options, maybe? Many thanks.
f

2

Try:
graph->SetTitle("global title;X axis title;Y axis title;Z axis title");

3

thank you

4

Maybe you could try this (I get no problem with the “new Y axis title”):

#include "TGraph.h"
#include "TAxis.h"

TGraph * title(void) {
  Double_t x[10] = {0,1,2,3,4,5,6,7,8,9};
  Double_t y[10] = {9,8,7,6,5,4,3,2,1,0};
  TGraph *graph = new TGraph(10, x, y);
  graph->SetTitle("graph title");
  // graph->SetTitle("global title;X axis title;Y axis title;Z axis title");
  graph->GetYaxis()->SetTitle("new Y axis title");
  graph->Draw("AL*");
  return graph;
}

See maybe also: https://root-forum.cern.ch/t/order-of-calling-methods-with-tmultigraph/14724/1

5

the problem not solved. it does not complain however.
I have both the includes, and this sequence :

............
graph->SetTitle("graph title");
graph->GetYaxis()->SetTitle("new Y axis title");
graph->Draw("AL*");
return graph
6

Maybe you could try:
graph->GetHistogram()->GetYaxis()->SetTitle("new Y axis title");

7

Messages in response to above:

Error: Failed to evaluate graph->GetHistogram()
Error: Failed to evaluate graph->GetHistogram()->GetYaxis()
Error: Failed to evaluate graph->GetHistogram()->GetYaxis()->SetTitle(“new Y axis title”)

8

Try to run this (again, I get no problem with the “new Y axis title”):

#include "TGraph.h"
#include "TAxis.h"
#include "TH1.h"

TGraph * title(void) {
  Double_t x[10] = {0,1,2,3,4,5,6,7,8,9};
  Double_t y[10] = {9,8,7,6,5,4,3,2,1,0};
  TGraph *graph = new TGraph(10, x, y);
  graph->SetTitle("graph title");
  // graph->SetTitle("global title;X axis title;Y axis title;Z axis title");
  // graph->GetYaxis()->SetTitle("new Y axis title");
  graph->GetHistogram()->GetYaxis()->SetTitle("new Y axis title");
  graph->Draw("AL*");
  return graph;
}

Note: I add several “#include” statements in order to be able to precompile it using ACLiC (i.e. “root [0] .x title.cxx++”)

9

the same set of errors. yes, all includes are present.

10

What’s you ROOT version, Operating System version, compiler version?
(I tried ROOT 5.28 and 5.34 on Linux i686 and x86_64 and gcc 4.4.[36].)

Well, maybe you need to report a bug.

11

root 5.20
Linux version 2.6.18-238.12.1.el5 (brewbuilder@norob.fnal.gov) (gcc version 4.1.2 20080704 (Red Hat 4.1.2-50)) #1 SMP
gcc version 4.1.2 20080704 (Red Hat 4.1.2-50)

12

This macro works for me on Mac with the ROOT trunck:

{
  Double_t x[10] = {0,1,2,3,4,5,6,7,8,9};
  Double_t y[10] = {9,8,7,6,5,4,3,2,1,0};
  TGraph *graph = new TGraph(10, x, y);
  graph->SetTitle("graph title");
  graph->GetHistogram()->GetYaxis()->SetTitle("new Y axis title");
  graph->Draw("AL*");
  return graph;
}

c1.gif696×474 4.44 KB

13

This works while the other suggestions did not.

14

That’s ok. But when we have to rename a X axis tiltle as tan_beta then what?
How can we write a character type title in Root?

15

what do you mean ?

16

I mean to say, If I have to write sin(theta) then how i will write it??
Theta not in text format but in symbolic form.

17

You’ll need to use the TLateX convention.

In your particular case:

graph->SetTitle("global title;sin(#theta);Y axis title;Z axis title");
18

Got it. Thankyou.
There is another problem how can we allign a title at centre?

19 
graph->GetXaxis()->CenterTitle(true);
20

Thanks alot.