Hi Eric,
A problem in TNode::Master2Local in a configuration like yours was fixed
by Robert Hatcher on April 14 this year.
Unfortunately, you do not indicate which version you are using.
If you move to 3.05/05 or newer, I expect this problem to be solved.
Rene Brun
dumontei wrote:
>
> Hello,
>
> while trying to use TGeom (TNode,...) in AliRoot, I noticed a pb which
> can be seen in this basic macro:
>
> {
> gROOT->LoadMacro("loadlibs.C");
> loadlibs();
> TFile *file = new TFile("galice.root");
> if (!gAlice)
> {
> gAlice = (AliRun*)file->Get("gAlice");
> if (gAlice) printf("AliRun object found on file\n");
> if (!gAlice) gAlice = new AliRun("gAlice","Alice test program");
> }
>
> char namech[10];
> char name[10];
>
> sprintf(name,"SLAT_N%d",slatnum);
>
> // Converting local -> master
> Float_t local[3],local2[3], master[3];
> local[0] = x1;
> local[1] = y1;
> local[2] = 0;
> TNode *node = gAlice->GetGeometry()->GetNode(name);
> node->UpdateMatrix();
> node->Local2Master(local,master);
> cout<<"local "<<local[0]<<" "<<local[1]<<" "<<local[2] << endl;
> cout<<" master "<<master[0]<<" "<<master[1]<<" "<<master[2]<<endl;
> node->UpdateMatrix();
> node->Master2Local(master,local2);
> cout<<"local2 "<<local2[0]<<" "<<local2[1]<<" "<<local2[2] << endl;
> }
>
> which give this outpout (this is not normal since we have to found the
> same starting and ending values...):
>
> local 10 3 0
> master 75.7508 68.2644 986
> local2 9.73511 3.77195 1.63918e-15
> (int)1085958144
>
> Maybe the same problem was describe in this ROOT Talk, but this question
> had no answear:
>
> From: Volker Hejny (V.Hejny@fz-juelich.de)
> Date: Tue Aug 28 2001 - 08:30:19 MEST
>
> Next message: Christian Holm Christensen: "Re: [ROOT] add
> histogram"
> Previous message: Rene Brun: "Re: [ROOT] add histogram"
> Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
>
> Hi all,
>
> I tried to use TGeometry and played with the transformation
> function Master2Local and Local2Master. While the latter
> worked properly, the other did not what I assumed. On
> closer look I found, that the same matrix is used as
> in Local2Master. Instead the transposed should be used.
>
> Best regards,
> Volker
>
> --
> Dr. Volker Hejny Tel: 02461/616853
> **
> Institut f. Kernphysik Fax: 02461/613930 **
>
> ---------------------------------------------------------------- ** **
> ---
> Forschungszentrum Juelich GmbH, D-52425 Juelich **
>
> Thanks a lot in advance,
>
> Eric
This archive was generated by hypermail 2b29 : Thu Jan 01 2004 - 17:50:12 MET