Re: TClonesArray::Streamer expecting class

From: Dmitry Naumov <naumov_at_nusun.jinr.ru>
Date: Tue, 16 Aug 2005 12:03:50 +0200


Hi Philippe,

this is easy if you have installed VMC, and G4. The sources are compiled and cleaned as usual "make" and "make clean" from the top directory nuclon. To generate the file please open the root session and run:
root[].x run_g4.C

To control the number of events please edit macros/test1.C

Thank you for your efforts,
best regards,

    Dmitry

Philippe Canal wrote:

>Hi,
>
>There is indeed something odd with the file nuclon.root.
>How can I regenerate it?
>
>Cheers,
>Philippe.
>
>-----Original Message-----
>From: Dmitry V.Naumov [mailto:naumov_at_lapp.in2p3.fr]
>Sent: Monday, August 15, 2005 9:51 AM
>To: Philippe Canal
>Cc: roottalk_at_cern.ch
>Subject: Re: [ROOT] TClonesArray::Streamer expecting class
>
>Hi Philippe,
>
>thank you for your answer and sorry for some delay with my answering (I
>was out of office).
>I tried what you suggested but unfortunatelly it did not help...
>I copied again the tar ball with my code, all libraries complied with
>gcc 3.3.5
>
>Reading specs from /usr/lib/gcc-lib/i486-linux/3.3.5/specs
>Configured with: ../src/configure -v
>--enable-languages=c,c++,java,f77,pascal,objc,ada,treelang --prefix=/usr
>--mandir=/usr/share/man --infodir=/usr/share/info
>--with-gxx-include-dir=/usr/include/c++/3.3 --enable-shared
>--enable-__cxa_atexit --with-system-zlib --enable-nls
>--without-included-gettext --enable-clocale=gnu --enable-debug
>--enable-java-gc=boehm --enable-java-awt=xlib --enable-objc-gc i486-linux
>Thread model: posix
>gcc version 3.3.5 (Debian 1:3.3.5-13)
>
>and file nuclon.root (I did not include it last time because it can be
>generated with run_g4.C).
>To give you some filling on the problem. If I dump TClonesArray
>*fDetResponse then I see
>that it is always filled with some hits, etc. However reading back the
>events from the root
>file (new root session) I meet "TClonesArray expecting class..." which
>happenes because
>the pointer fDetResponse is not NULL while somewhy it has zero entries...
>
>Thank you in advance, Dmitry
>
>Philippe Canal wrote:
>
>
>
>>Hi Dmitry,
>>
>>I tried and failed to reproduce your problem (It ask for a file
>>
>>
>nuclon.root)
>
>
>>However, it sounds like the TTree still sees the address of the deleted
>>TClonesArray.
>>It would be better if, you function was more like (i.e. keep the existing
>>object alive):
>>
>>void NEvent::SetDetectorResponse(TClonesArray* copy) {
>> fDetResponse->Clear();
>> for() {
>> new ( (*fDetResponse)[i] ) ObjectType( copy->At(i) );
>> }
>>}
>>
>>Cheers,
>>Philippe.
>>
>>-----Original Message-----
>>From: owner-roottalk_at_pcroot.cern.ch [mailto:owner-roottalk_at_pcroot.cern.ch]
>>On Behalf Of Dmitry V.Naumov
>>Sent: Wednesday, August 10, 2005 8:48 AM
>>To: roottalk_at_cern.ch
>>Subject: [ROOT] TClonesArray::Streamer expecting class
>>
>>Dear rooters,
>>
>>I have the following problem which I can not figure out myself.
>>As the output of VMC+G4 code I save the root file with TTree
>>containg NEvent as a branch. The structure of this event is very
>>simple:
>>
>>class NEvent: public TObject {
>>public:
>><skip>
>>private:
>>
>>NEventHeader *fHeader; // Event header
>>TClonesArray *fDetResponse; // -> detector response with hits, etc
>>TObjArray *fTracks; // -> tracks
>>};
>>
>>In the code I have the pointer of type NEvent which I fill with needed
>>information. For example I use methods like:
>>void NEvent::SetDetectorResponse(TClonesArray* copy) {
>>fDetResponse = (TClonesArray*)copy->Clone();
>><skip>
>>}
>>
>>in order to delete consequently copy from the main body of the code.
>>Finally the tree is saved with usual TTree::Fill() method.
>>What I get sometimes (and this is what I do not understand) that reading
>>back
>>the output from the root file reading of some events gives:
>>TClonesArray::Streamer expecting class
>>
>>To be more precise:
>>
>>Reading 2 event
>>Reading 3 event
>>Reading 4 event
>>TClonesArray::Streamer expecting class 4?}`
>>Reading 5 event
>>TClonesArray::Streamer expecting class
>>Error in <TBuffer::CheckByteCount>: object of class TClonesArray read
>>too few bytes: 15 instead of 625760311
>>Error in <TBuffer::CheckByteCount>: Byte count probably corrupted around
>>buffer position 6807:
>>625760311 for a possible maximum of 25174
>>
>>I was checking in the core of the code that the pointer I pass to my
>>NEvent is
>>not empty, some slots of TClonesArray are always filled. Doing
>>TTree::Print() before
>>closing the file looks also OK:
>>
>>***************************************************************************
>>
>>
>*
>
>
>>**
>>
>>*Tree :nuclon : nuclon tree *
>>*Entries : 6 : Total = 242395 bytes File Size = 74081 *
>>* : : Tree compression factor = 2.98 *
>>***************************************************************************
>>
>>
>*
>
>
>>**
>>
>>*Branch :fEvent *
>>*Entries : 6 : BranchElement (see below) *
>>*..........................................................................
>>
>>
>.
>
>
>>.*
>>
>>*Br 0 :fUniqueID : *
>>*Entries : 6 : Total Size= 682 bytes One basket in memory *
>>*Baskets : 0 : Basket Size= 32000 bytes Compression= 1.00 *
>>*..........................................................................
>>
>>
>.
>
>
>>.*
>>
>>*Br 1 :fBits : *
>>*Entries : 6 : Total Size= 658 bytes One basket in memory *
>>*Baskets : 0 : Basket Size= 32000 bytes Compression= 1.00 *
>>*..........................................................................
>>
>>
>.
>
>
>>.*
>>
>>*Br 2 :fHeader : *
>>*Entries : 6 : Total Size= 1400 bytes One basket in memory *
>>*Baskets : 0 : Basket Size= 32000 bytes Compression= 1.00 *
>>*..........................................................................
>>
>>
>.
>
>
>>.*
>>
>>*Br 3 :fDetResponse : *
>>*Entries : 6 : Total Size= 237055 bytes File Size = 74081 *
>>*Baskets : 1 : Basket Size= 32000 bytes Compression= 2.98 *
>>*..........................................................................
>>
>>
>.
>
>
>>.*
>>
>>*Br 4 :fTracks : *
>>*Entries : 6 : Total Size= 824 bytes One basket in memory *
>>*Baskets : 0 : Basket Size= 32000 bytes Compression= 1.00 *
>>*..........................................................................
>>
>>
>.
>
>
>>.*
>>
>>
>>On the root website I found some references for the similar problems
>>
>>
>>from which
>
>
>>I did not figure out the solution or diagnosis like:
>>http://root.cern.ch/root/roottalk/roottalk02/4747.html
>>
>>The tar ball with the code can be found at :
>>dnaumov_at_lxplus.cern.ch:~/public/nuc.tar.gz
>>The variables are set with source source_me.
>>The problem can be reproduced running run_g4.C
>>and then
>>root[].x EventAnalysis.C
>>click "next" 5-6 times to see it.
>>
>>Thanks in advance, Dmitry
>>
>>
>>
>>
>>
>>
>>
>
>
>
>
Received on Tue Aug 16 2005 - 10:03:23 MEST

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