Re: Setting bins for TTree.Draw

Rene Brun (brun@hpbrun.cern.ch)
Tue, 19 May 1998 22:19:36 +0200 (METDST)


Bill,
What you do is correct, EXCEPT the histogram type.
Use TH1F, not TH1

Rene Brun

On Tue, 19 May 1998, William Love wrote:

> Dear Roots
>
> I plot a histogram from a TTree (made with h2root) of
> an integer variable and ROOT picks bad bins. I tried to do
> TH1 *hrows = new TH1("hrows","TPC rows",45,0.5, 45.5);
> to set good bins and then
> h10.Draw("row>>+hrows");
> but I got
> Warning in <TTree::Draw>: Deleting old histogram with different dimensions
> and the same wrong-headed histogram. There seems to be no
> TTree.SetBins method. You used to could do graph/hplot/null in
> PAW and then draw on the premade plot. Must be able to do it
> in ROOT?
>
> Bill Love
>
>