I do not want to set the number of bins automatically, because it might be a
user error.
Simply clone one of the operands before dividing, instead of calling
the default constructor.
Rene Brun
Thomas Bretz wrote:
>
> Rene,
>
> yes, itmust. So why is the binning not automatically taken over?
>
> Thomas.
>
> Rene Brun wrote:
> > Thomas,
> >
> > The resulting histogram must have the same number of bins than the
> > operand histograms.
> >
> > Rene Brun
> >
> > On Thu, 18 Mar 2004, Thomas Bretz wrote:
> >
> >
> >>Hi Rene,
> >>
> >>why does h4 need the same number of bins? It is enough if h4 'takes' the
> >>binning from either h3 or h2, isn't it?
> >>
> >>Thomas.
> >>
> >>Rene Brun wrote:
> >>
> >>>Your two projections h2 and h3 have the same number of bins,
> >>>eg you can do h3->Divide(h2);
> >>>However, you call the default constructor for h4. h4 does not have the
> >>>same number of bins as h2 and h3.
> >>>Instead of
> >>> TH2D *h4 = new TH2D;
> >>> h4->Divide(h3, h2);
> >>>do
> >>> TH2D *h4 = (TH2D*)h2->Clone();
> >>> h4->Divide(h3, h2);
> >>>
> >>>Rene Brun
> >>>
> >>>Thomas Bretz wrote:
> >>>
> >>>
> >>>>Hi,
> >>>>
> >>>>I have a
> >>>>Double_t x[5] = { 0, 1, 2, 3, 4 };
> >>>>TH3D fHist("", "", 4, x, 4, x, 4, x);
> >>>>and do:
> >>>>fHist.GetZaxis()->SetRange(3, 4);
> >>>>TH1 *h2 = fHist.Project3D("xy_off"); //, -1, 9999, "E");
> >>>>
> >>>>fHist.GetZaxis()->SetRange(1,2);
> >>>>TH1 *h3 = fHist.Project3D("xy_on"); //, -1, 9999, "E");
> >>>>
> >>>>TH2D *h4 = new TH2D;
> >>>>h4->Divide(h3, h2);
> >>>>
> >>>>And I get
> >>>>Attempt to divide histograms with different number of bins...
> >>>>
> >>>>What am I doing wrong? I would expect to have two projections to have
> >>>>the same binning...
> >>>>
> >>>>Thomas.
> >>>
> >>>
> >
> >
This archive was generated by hypermail 2b29 : Sun Jan 02 2005 - 05:50:06 MET