[Z (bad) label for palette axis in TH3D

[Daniel_Cano-Ott]

Continuing the discussion from Z (bad) label for palette axis in TH3D:

@couet

Patch is applied

Dear Mr. Couet,

Could you please let me know how this was fixed/patched? I am using root 6.26/06 and get the same issue with a TH3D. The palette axis label is the same as the z axis.
Thanks in advance!

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ROOT Version: 6.26/06
Platform: OSX 12.6

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[couet]

Sorry, I do not remember. That’s an old think. Can you provide a small example showing the problem you encounter?

[Daniel_Cano-Ott]

Hi, the problem is that the zcol showing the palette appears with the same title as the z-axis of a 3D histogram. This is not correct since the color code corresponds to the bin content. See below the plot I generated with my (very long) macro.

Thanks in advance!

[couet]

Reproducer:

void testTH3Title() {
   auto C = new TCanvas();
   C->SetRightMargin(0.15);
   TRandom3 r;
   int nBins = 3;
   int nEvents = 1000;
   double minRange = 1; double maxRange = 5;
   TH3D* h4 = new TH3D("h4", "h4-Title",
                       2*nBins, minRange, maxRange,
                       nBins , minRange, maxRange,
                       nBins , minRange, maxRange);

   for ( Int_t e = 0; e < nEvents; ++e ) {
      Double_t x = r.Uniform(0.9 * minRange, 1.1 * maxRange);
      Double_t y = r.Uniform(0.9 * minRange, 1.1 * maxRange);
      Double_t z = r.Uniform(0.9 * minRange, 1.1 * maxRange);
      h4->Fill(x, y, z, 1.0);
   }
   h4->Draw("box2 z");
   h4->SetTitle("h4-Title;XXXXX;YYYYY;ZZZZZ");
}

I agree, the Z title should not de displayed along the palette.

[couet]

This PR fixes this issue:

TH3 palette title was equal to the z-axis title

Thanks to have seen it.

[Wile_E_Coyote]

@couet Maybe you could implement:
h4->SetTitle("h4-Title;XXXXX;YYYYY;ZZZZZ;TTTTT");

Z (bad) label for palette axis in TH3D

Maybe you could define a “T-axis” (ROOT already defines and uses 4 special variable names “x”, “y”, “z”, “t”).

[couet]

Yes that’s also an option. The fix I did makes it at least coherent for the axis with have now. @moneta what about a such new T axis ?

[Daniel_Cano-Ott]

Thank you very much.
Are you planning to add this fix to the next ROOT release?

[couet]

the T Axis? I am not sure, I would prefer that @moneta gives his point of view.
The fix is in the master now. The palette has no title in the case of TH3.

[moneta]

Hi,
I agree to have a function for TH3 like h4->SetTitle("h4-Title;XXXXX;YYYYY;ZZZZZ;TTTTT");, but I would not like having another axis stored inside the histogram class. We should think about a solution for setting correctly the palette axis of a multi-dim histogram

Lorenzo

[Daniel_Cano-Ott]

Hi, I just installed the new ROOT release (6.28/00) on my Mac (OSX 12.6) and the problem is still there. Do you have a hint when the fix will be released?
Thanks in advance.

[couet]

I applied the fix in the master version only.

[Wile_E_Coyote]

Well, it’s an old thread, but … I’ve accidentally faced this problem again.
So, has anything changed in the meantime?
Is there now any possibility to define the title of the “T-axis” (palette’s title) for the TH3?

[couet]

I have done something:

void testTH3Title() {
   gStyle->SetOptStat(0);
   auto C = new TCanvas();
   C->Divide(2,1);

   C->cd(1)->SetRightMargin(0.2);
   auto h2 = new TH2F("h2","h2",10,0.,1.,10,0.,1.);
   h2->SetTitle("h2-Title;XXXXX;YYYYY;ZZZZZ;TTTTTT");
   h2->Fill(0.5, 0.5,10.);
   h2->Draw("COLZ");

   C->cd(2)->SetRightMargin(0.2);
   auto h3 = new TH3D("h3", "h3",10, 1., 5.,10 , 1., 5.,10 , 1., 5.);
   h3->Fill(3, 3, 3, 10.);
   h3->Draw("box2 z");
   h3->SetTitle("h3-Title;XXXXX;YYYYY;ZZZZZ;TTTTTT");
}

I’ll make a PR

[couet]

PR here. (merged)