Force the exponent on the y-axis of a TGraph

[faca87]

Hello, is there a way to force the exponent of the scientific notation in the TGraph?

I mean, I get a scale *10^-6. I would like to get in 10^-5

I even tried the DrawFrame as @couet used here TGraph set maximum number of digits not working - #6 by couet, in addition to the SetMaxDigits, but without results…

lcdata.txt (72 Bytes)

lcplot.cpp (2.3 KB)

[ferhue]

A workaround would be:

graph->Scale(1./1e-5, "y");
graph->GetYaxis()->SetTitle("Flux Mev ...  / 1e-5)

[couet]

Yes the power of 10 are multiple of 3. Note that in you example DrawFrame is useless as you draw the graph with option "A’ which will redraw the axis.

[faca87]

thank you the both.
i tried the scale, but the points disappear and i still get 10^-6

lcdata.txt (72 Bytes)

lcplot.cpp (2.3 KB)

[ferhue]

Try calling Scale earlier in the script, just after new TGraphErrors

@couet do you know why it depends on what position it is called frmo?

[couet]

The following works for me:

void lcplot() {
   TGraphErrors *graph1 = new TGraphErrors("LCdata.txt","%lg %lg %lg %lg");
   graph1->Scale(1./1e-5, "y");
   graph1->Draw("AP");
}

[ferhue]

Ok, thanks, so this works:

void lcplot() {
   TGraphErrors *graph1 = new TGraphErrors("LCdata.txt","%lg %lg %lg %lg");
   graph1->Scale(1./1e-5, "y");
   graph1->GetXaxis()->SetLimits(60479, 60492);
   graph1->Draw("AP");
}

but this fails:

void lcplot() {
   TGraphErrors *graph1 = new TGraphErrors("LCdata.txt","%lg %lg %lg %lg");
   graph1->GetXaxis()->SetLimits(60479, 60492);
   graph1->Scale(1./1e-5, "y");
   graph1->Draw("AP");
}

Not sure if Scale should be modified to update the y-limits if x-limits were set.

[faca87]

Hello, thank you.
Moving the

graph1->Scale(1./1e-5, "y");

just after
GraphErrors *graph1 = new TGraphErrors("LCdata.txt","%lg %lg %lg %lg");

set the 10^-5 scale…
but the 10^-5 factor
lcdata.txt (72 Bytes)

lcplot.cpp (2.3 KB)
disappears…

[ferhue]

@faca87

disappears…

Yes, it disappears, that’s the idea / trick. Set it instead in the Y-axis title.

graph1->GetYaxis()->Settitle (“flux / 1e-5”);

[faca87]

Unfortunately, it’s quite orrible to write it in the y-title…

[ferhue]

You can write it instead as a TText or TLatex object at the desired position.

[faca87]

Yes good solution!