[ROOT] Setting axes for graphs

From: Maurizio Loreti (loreti@pd.infn.it)
Date: Fri Mar 08 2002 - 08:19:43 MET 

Hi there -
I am trying to make a slide with some data.  The file I am using with root
(version 3.02.07, linux distribution 6.1/egcs) is:

{
const Int_t n1=12;
Double_t x1[n1];
const Double_t y1[n1] = {
  18.606, 26.434, 32.393, 37.443, 41.799, 45.858,
  49.540, 52.971, 56.183, 59.204, 62.078, 64.832
};

for (Int_t i = 0;  i < n1;  ++i) x1[i]=sqrt(i+1);

TCanvas *c1 = new TCanvas("c1", "c1");
c1->SetFillColor(0);

TGraph *g1 = new TGraph(n1, x1, y1);
g1->SetMarkerStyle(2);
g1->SetMarkerSize(0.9);
// g1->GetXaxis()->SetLimits(0.0, 4.0);
// g1->GetYaxis()->SetLimits(10.0, 70.0);
g1->Draw("AP");
}

So far, so good.  ".x foo.C" does what it is supposed to do.  But - if I
try to define the X- and Y-axis limits to some integer/meaningful number
in the two commented lines, I get "*** Break *** segmentation violation".

What am I doing wrong?  x->GetXaxis()->SetLimits() works correctly if x
points to an histogram.  What is the way to change the axis limits for
graphs?

		TIA,	M.

-- 
Maurizio Loreti                         http://www.pd.infn.it/~loreti/mlo.html
Univ. of Padova, Dept. of Physics - Padova, Italy            loreti@pd.infn.it

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