problem with passing arrays in TF2.Draw()

From: Petar Maksimovic (petar@heplcdf1.harvard.edu)
Date: Sun May 10 1998 - 05:24:05 MEST 

Fellow rooters,

I would appreciate if somebody could spare a minute and look over (and
perhaps try running) the macro given below, in which I attempt to plot
a trivial 2-D function (using TF2.Draw()).  I'm using root 2.00/05,
and the problem exists on both IRIX 6.2 and Linux RedHat 5.0.

Thanks a lot!

	Petar



// file: test.C
//____________________________________________________________________________
// tfun2() called from tfun1()
//
Double_t tfun2( Double_t *ee)
{
  printf("ee[] = %f %f %f\n", ee[0], ee[1], ee[2]);
  return ee[0]+ee[1]+ee[2];
}

//____________________________________________________________________________
//  tfun1() is used in TF2 constructor and called by TF2.Draw()
//
Double_t tfun1(Double_t *x, Double_t *par)
{
  Double_t res;       // the result
  Double_t xe[3];     // the array we'll try to pass

  // put some values in xe[] (they are arbitrary)
  xe[0] = x[1] + 0.845;
  xe[1] = x[2] * x[1] * 0.246;
  xe[2] = 0.941;

  printf("xe[] = %f %f %f\n", xe[0], xe[1], xe[2]);

  // call tfun2()
  res = tfun2(xe);

  printf("Result = %f\n", res);
  return res;
}

I load and execute the above functions with:

root [0] .L test.C
root [1] TF2 *f2 = new TF2("test",tfun1,0,1,0,1,0);
root [2] f2->Draw()

And get hundreds of the following error messages:

Error: Array index out of range xe+2147351296  valid upto xe[2] FILE:/home/lv48/petar/root/./test.C LINE:10
Error: Array index out of range xe+1072569516  valid upto xe[2] FILE:/home/lv48/petar/root/./test.C LINE:10
Error: Array index out of range xe+57  valid upto xe[2] FILE:/home/lv48/petar/root/./test.C LINE:10
xe[] = 0.941000 0.000000 0.941000


The problem does not appear when I call tfun1() interactively,
e.g. by creating x,par in root shell, and printing its value:

root[77] printf("%f\n", tfun1(x,par));


Am I overlooking something?  Thanks for any ideas on where to look...

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