Re: Failure in TTree filling

From: Francois-Xavier Girod <fxgirod_at_jlab.org>
Date: Fri, 30 Jun 2006 08:17:22 -0400 (EDT)

Dear rooters,

I am using root version 5.11/06, but the problem also appears on earlier versions.

What should I do if I want to write several trees in several files ?

I did

     TFile *f1 = new TFile(...)
     TTree *T1 = new TTree(...)
     T1->Branch...
     ...
     TFile *f2 = new TFile(...)
     TTree *T2 = new TTree(...)
     T2->Branch...
     ...

...
(process stuff and fill variables)
...

f1->cd()
T1->Fill()
f2->cd()
T2->Fill()

...

f1->cd()
T1->Write()
f2->cd()
f2->Write()

f2 file is ok, with T2 tree containing its data. However, f1 file contains T1 tree, which has correct keys (for instance I can get the number of events or the list of leaves) but contains no data. More specifically if I try to draw something I get :

Error in <TFile::ReadBuffer>: error reading all requested bytes from file outTreeResultDVCS.root, got 0 of 29892

I should add that, this only happens for the analysis of a large number of events. When I process a few events, the output is correct.

My guess is that, the way I proceed only the last declared tree is disk resident, whereas the previous ones are memory resident.

Thank you for help.

Regards,

        Francois-Xavier

--

Girod Francois-Xavier

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On Wed, 28 Jun 2006, Rene Brun wrote:



> When this message is printed with teh CVS head version, you also get the

> following print:

>

>  This error is symptomatic of a Tree created as a memory-resident Tree

>  Instead of doing:

>     TTree *T = new TTree(...)

>     TFile *f = new TFile(...)

>  you should do:

>     TFile *f = new TFile(...)

>     TTree *T = new TTree(...)

>

>

> Rene Brun

>

> Alberto Pulvirenti wrote:

> > Dear rooters,

> >

> > sometimes, while filling a TTree, I encountered this message:

> >

> > Error in <TTree::Fill>: Failed filling branch:matches.matches, nbytes=-1

> >

> > can someone explain me what does it mean? What mistake did I do while

> > creating the code to fill that TTree?

> > For completeness I must say that this TTree is filled with a branch

> > made from a  struct of primitive data types.

> >

> > Thanks,

> >

> >     Alberto

> >

> > **************************************

> > ----- Alberto Pulvirenti, Ph. D. -----

> >  Universita' di Catania,

> >  Dipartimento di Fisica e Astronomia

> >  Via Santa Sofia, 64

> >  I-95129, Catania, Italy

> >

> >  Tel :+39-095-3785286

> > **************************************

>

>

Received on Fri Jun 30 2006 - 14:17:34 MEST