Re: Creating a vector of pointers to histograms - problem.

Hello all.

First of all, thanks for all your help. Eddy, the solution you offered initially didn't quite work, unless I kept the files open during each loop (which was something I didn't want do). However, Philippe's tip about the behaviour of the TH1 constructor really ended the enigma, I think.

Thank you all for all your help,
Thiago

On Nov 14, 2007 12:25 AM, Edmond Offermann <edmondoffermann_at_yahoo.com> wrote:
> Hi Thiago,
>
> Inside your loop you have a variable histoA which will be destroyed
> after each iteration . Replace you stuff by :
>
> vector<TH1I*> groupA;
> vector<TH1I*> groupB;
>
> while ((chEl=(TChainElement*)next() )) {
> TFile f(chEl->GetTitle());
>
> TH1D *histoA = (TH1D *) f.Get("hA");
> histoA->SetName("newhA);
> groupA.push_back(histoA);
>
> TH1D *histoB = (TH1D *) f.Get("hB");
> histoB->SetName("newhB);
> groupB.push_back(histoB);
>
> f.Close();
> }
> }
>
> Eddy
>
>
> --- Thiago Tomei <Thiago.Tomei_at_cern.ch> wrote:
>
> > Dear ROOTers
> >
> > The solution from Philippe worked perfectly (by the way, many thanks.
> > :) , but still it will not quite solve my problems. What I want to do
> > is:
> >
> > 1) Open a file, with a name given by a string constructed in run time
> > (so I can loop over files)
> > 2) Get all the histograms that exist in that file, according to their
> > categories (for instance, the histogram of momenta, the histogram of
> > energies, etc.), and copy them in containers (could be std::vectors,
> > TObjArrays, whatever works best). So, I would have a container of
> > momenta histograms, a container of energies histogram, etc...
> > 3) Close the file and go back to 1). Loop over all the files.
> >
> > I want to access the histograms, which were (hopefully) saved in the
> > containers, after the loop is done. I came up with the following
> > code:
> >
> > void group() {
> >
> > TChain ch("anything");
> > string files; // I will construct this string during runtime.
> > // ... constructs the string...
> > ch.Add(files.c_str());
> >
> > TObjArray* fileElements = ch.GetListOfFiles();
> > TIter next(fileElements);
> > TChainElement* chEl = 0;
> >
> > vector<TH1I> groupA;
> > vector<TH1I> groupB;
> >
> > while ((chEl=(TChainElement*)next() )) {
> > TFile f(chEl->GetTitle());
> >
> > TH1D histoA;
> > f.Get("hA")->Copy(histoA);
> > histoA.SetName("newhA);
> > groupA.push_back(histoA);
> >
> > TH1D histoB;
> > f.Get("hB")->Copy(histoB);
> > histoB.SetName("newhB);
> > groupB.push_back(histoB);
> >
> > f.Close();
> > }
> > }
> >
> > and the strange thing is: the first trip through the loop, everything
> > works fine! However, during the second trip, it crashes just before I
> > push histoA to the groupA. The macro compiles with no problems, but
> > segfaults with the following backtrace:
> >
> > #0 0xb695b360 in TH1D::TH1D () from /usr/lib/root/5.17/libHist.so
> > #1 0xb5f3d289 in std::vector<TH1D, std::allocator<TH1D>
> > >::_M_insert_aux ()
> > from /home/trtomei/Desktop/WZjets/scanning_old/./teste2_C.so
> > #2 0xb5f3c3c3 in teste2 ()
> > from /home/trtomei/Desktop/WZjets/scanning_old/./teste2_C.so
> > #3 0xb5f3cd47 in G__fileCn2kaN__0_1198 ()
> > from /home/trtomei/Desktop/WZjets/scanning_old/./teste2_C.so
> > #4 0xb727a4e7 in Cint::G__ExceptionWrapper ()
> > from /usr/lib/root/libCint.so.5.17
> > #5 0xb73636e0 in G__call_cppfunc () from
> > /usr/lib/root/libCint.so.5.17
> > #6 0xb733cba5 in G__interpret_func () from
> > /usr/lib/root/libCint.so.5.17
> > #7 0xb732b6b7 in G__getfunction () from
> > /usr/lib/root/libCint.so.5.17
> > #8 0xb72ffdf2 in G__getitem () from /usr/lib/root/libCint.so.5.17
> > #9 0xb7306865 in G__getexpr () from /usr/lib/root/libCint.so.5.17
> > #10 0xb731217a in G__calc_internal () from
> > /usr/lib/root/libCint.so.5.17
> > #11 0xb739b441 in G__process_cmd () from
> > /usr/lib/root/libCint.so.5.17
> > #12 0xb79c4275 in TCint::ProcessLine () from
> > /usr/lib/root/libCore.so.5.17
> > #13 0xb79be086 in TCint::ProcessLineSynch () from
> > /usr/lib/root/libCore.so.5.17
> > #14 0xb792647b in TApplication::ExecuteFile ()
> > from /usr/lib/root/libCore.so.5.17
> > #15 0xb79267b4 in TApplication::ProcessFile ()
> > from /usr/lib/root/libCore.so.5.17
> > #16 0xb7923ddb in TApplication::ProcessLine ()
> > ---Type <return> to continue, or q <return> to quit---
> > from /usr/lib/root/libCore.so.5.17
> > #17 0xb7213a89 in TRint::HandleTermInput () from
> > /usr/lib/root/libRint.so.5.17
> > #18 0xb7211f75 in TTermInputHandler::Notify ()
> > from /usr/lib/root/libRint.so.5.17
> > #19 0xb72143e4 in TTermInputHandler::ReadNotify ()
> > from /usr/lib/root/libRint.so.5.17
> > #20 0xb79f059b in TUnixSystem::CheckDescriptors ()
> > from /usr/lib/root/libCore.so.5.17
> > #21 0xb79f098e in TUnixSystem::DispatchOneEvent ()
> > from /usr/lib/root/libCore.so.5.17
> > #22 0xb797bce1 in TSystem::InnerLoop () from
> > /usr/lib/root/libCore.so.5.17
> > #23 0xb797d631 in TSystem::Run () from /usr/lib/root/libCore.so.5.17
> > #24 0xb7922858 in TApplication::Run () from
> > /usr/lib/root/libCore.so.5.17
> > #25 0xb721401e in TRint::Run () from /usr/lib/root/libRint.so.5.17
> > #26 0x08048ea3 in main ()
> >
> > Regards,
> > Thiago
> >
> > On Nov 12, 2007 4:17 AM, Philippe Canal <pcanal_at_fnal.gov> wrote:
> > > Hi Thiago,
> > >
> > > This is a problem with the bytecode compiler. You can work around
> > > it by issuing the CINT command .O 0
> > > which disables the byte code compilation or better yet, you can
> > > simply compile your code via ACLiC (which will lead you to correct
> > > a few mistake including the wrong placement of the declaration of
> > f).
> > >
> > > Cheers,
> > > Philippe
> > >
> > >
> > > -----Original Message-----
> > > From: owner-roottalk_at_root.cern.ch
> > [mailto:owner-roottalk_at_root.cern.ch] On
> > > Behalf Of Thiago Tomei
> > > Sent: Saturday, November 10, 2007 6:06 AM
> > > To: roottalk_at_cern.ch
> > > Subject: [ROOT] Creating a vector of pointers to histograms -
> > problem.
> > >
> > > (I have already sent this message to roottalk_at_root.cern.ch, but it
> > > didn't appear anywhere - I take it that roottalk_at_root.cern.ch is
> > NOT
> > > an alias to roottalk_at_cern.ch. If another copy of this message
> > appears
> > > floating around, my apologies.)
> > >
> > > Dear ROOTers.
> > >
> > > I am trying to declare a vector of pointers to histograms, adding
> > > histograms inside the loop, and accessing the histograms after the
> > > loop is done. However, I am not able to do it, and I cannot figure
> > out
> > > why. Here's the relevant code:
> > >
> > > #include <iostream>
> > > #include <vector>
> > > #include "TFile"
> > > #include "TH1"
> > >
> > > int test() {
> > >
> > > using namespace std;
> > >
> > > vector <TH1I*> vechist;
> > >
> > > do {
> > > cout << "in the loop..." << endl;
> > > TFile* f = new TFile("rootfile.root");
> > > TH1I* temphist = (TH1I*) f->Get("histogram");
> > > vechist.push_back(temphist);
> > > cout << "off the loop..." << endl;
> > > } while(0);
> > > cout << vechist[0]->GetEntries() << endl;
> > > f->Close();
> > >
> > > return 0;
> > > }
> > >
> > > It crashes just before the third cout. I thought it was a scope
> > > problem, but removing the do and the while(0), while still keeping
> > the
> > > curly braces (thus defining a scope inside) makes the problem
> > > disappear. What am I doing wrong? What can I do to solve my
> > problem?
> > >
> > > I am using ROOT 5.17/04, in an Ubuntu 7.10 machine.
> > >
> > > The output from bt command from the debugger:
> > >
> > > #0 0x53e58955 in ?? ()
> > > #1 0xb68bcd1d in ?? () from /usr/lib/root/5.17/libHist.so
> > > #2 0xb72d54e7 in Cint::G__ExceptionWrapper ()
> > > from /usr/lib/root/libCint.so.5.17
> > > #3 0xb73be6e0 in G__call_cppfunc () from
> > /usr/lib/root/libCint.so.5.17
> > > #4 0xb7397ba5 in G__interpret_func () from
> > /usr/lib/root/libCint.so.5.17
> > > #5 0xb7386651 in G__getfunction () from
> > /usr/lib/root/libCint.so.5.17
> > > #6 0xb74569b8 in G__getstructmem () from
> > /usr/lib/root/libCint.so.5.17
> > > #7 0xb744d802 in G__getvariable () from
> > /usr/lib/root/libCint.so.5.17
> > > #8 0xb735ad11 in G__getitem () from /usr/lib/root/libCint.so.5.17
> > > #9 0xb736a79f in G__getexpr () from /usr/lib/root/libCint.so.5.17
> > > #10 0xb73e2151 in G__exec_statement () from
> > /usr/lib/root/libCint.so.5.17
> > > #11 0xb7398f1b in G__interpret_func () from
> > /usr/lib/root/libCint.so.5.17
> >
> === message truncated ===
>
>

-- 
    Thiago R. F. P Tomei - http://cern.ch/Thiago.Tomei
    SPRACE - São Paulo Regional Analysis Center
    CERN - European Organization for Nuclear Research