Hi Chris,
Histograms with asymmetric errors are not supported. But it is quite easy
to get the same functionality via TGraphAsymmErrors. Here is a small
example
void gaerrors() {
TCanvas *c1 = new TCanvas("c1");
c1->SetGrid();
const Int_t n = 10;
Float_t x[n];
Float_t y[n] = {1,2.9,5.6,7.4,9,9.6,8.7,6.3,4.5,1};
Float_t exl[n] = {.5,1,.7,.7,.4,.5,.6,.7,.8,.5};
Float_t eyl[n] = {.8,.7,.6,.5,.4,.4,.5,.6,.7,.8};
Float_t exh[n] = {.2,.8,.5,.5,.3,.3,.4,.5,.6,.3};
Float_t eyh[n] = {.6,.5,.4,.3,.2,.2,.3,.4,.5,.6};
TH1F *h = new TH1F("h","Asymm errors histogram with labels",n,0,n);
const char *labels[n] = {"Chris","John","Rene","Fons","Marc",
"Fred", "Ted","Louis","Ed","Jim"};
for (Int_t i=0;i<n;i++) {
x[i] = h->GetXaxis()->GetBinCenter(i+1);
h->GetXaxis()->SetBinLabel(i+1,labels[i]);
h->Fill(x[i],y[i]);
}
h->Draw("a");
//h->GetXaxis()->LabelsOption("v");
gr = new TGraphAsymmErrors(n,x,y,exl,exh,eyl,eyh);
gr->SetMarkerStyle(21);
gr->Draw("p");
}
Rene Brun
On Fri, 18 Jan 2002, Chris Hays wrote:
>
> I can't seem to find a function that lets me set an asymmetric error for
> a single TH1F bin, only for a TGraph bin. Does one exist? I would prefer
> an asymmetric TH1F error so I can use the TH1F functionality, particularly
> SetBinLabel and "same" (maybe these are possible with TGraph, but I am
> not aware of it).
>
>
> Chris
>
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