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

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 === Received on Wed Nov 14 2007 - 00:25:42 CET