> (I am not quite sure if this would make sense?)
What you are trying to do, doesn't seem very general and implement
this proposal seems that it would have negative consequence for
everybody else (more problem about object ownership)
It would probably be better if you were either creating the
correct list of TTree friend in the first place or if you were managing
your own lists instead of relying on list (the list of friends)
which only vaguely support your use case.
Cheers,
Philippe.
Note: Also if you very to manage the TFile object and TTree object
by yourself and add the tree friend by passing a TTree* instead of
a string, the TFriendElement would __not__ own the TTree and would
not delete it upon removal.
-----Original Message-----
From: cstrato [mailto:cstrato@aon.at]
Sent: Thursday, April 15, 2004 4:33 PM
To: Philippe Canal
Cc: Rene Brun; roottalk@pcroot.cern.ch
Subject: Re: [ROOT] How to separate tree friends
Dear Philippe
I understand, however it would be great if there would be
a simpler way, e.g if there would exist a method such as:
TTree * TTree::RemoveFriend(const char *treename)
which removes the tree from the list of friends and returns
a pointer to the removed tree.
(I am not quite sure if this would make sense?)
Best regards
Christian
Philippe Canal wrote:
> Hi Christian,
>
> In your case the TFriendElements owns the TTree object (and the file)
> and is deleted when RemoveFriend is called.
>
> You will need to record the name of the TTree and the name of the
> file before Removing the friendship from the previous tree.
>
> Cheers,
> Philippe.
>
> -----Original Message-----
> From: cstrato [mailto:cstrato@aon.at]
> Sent: Wednesday, April 14, 2004 4:55 PM
> To: Philippe Canal
> Cc: Rene Brun; roottalk@pcroot.cern.ch
> Subject: Re: [ROOT] How to separate tree friends
>
>
> Dear Philippe,
>
> I have tried to implement your suggestion in the attached
> macro "macroFriends.C". Sorrowly, I get the following output:
> root [0] .x macroFriends.C
> ------MyClass::MyClass------
> ------MyClass::CreateTrees------
> ------MyClass::CreateTrees------
> ------MyClass::AddTree------
> ------MyClass::AddTree------
> ------MyClass::AddTree------
> ------MyClass::AddTree------
> ------MyClass::AddTree------
> ------MyClass::AddTree------
> ------MyClass::AddTree------
> ------MyClass::AddTree------
> ------MyClass::MoveTree------
> Error in <TMemberInspector::Streamer>: version id <=0 in ClassDef, dummy
> Streamer() called
> Error in <TMemberInspector::Streamer>: version id <=0 in ClassDef, dummy
> Streamer() called
> Error in <TMemberInspector::Streamer>: version id <=0 in ClassDef, dummy
> Streamer() called
> ------MyClass::GetTreeX------
> nfriends(treeX) = 3
> ------MyClass::GetTreeY------
>
> *** Break *** bus error
> Root > Function macroFriends() busy flag cleared
> Function GetTreeY() busy flag cleared
>
> Can you tell me, why I cannot add the selected trees to fTreeY?
>
> Thank you in advance
> Christian
>
>
> Philippe Canal wrote:
>
>>Hi Christian,
>>
>>The TTree object has one list of friend and it always
>>uses all the friends on the list.
>>
>>However you can manipulate the list as you see fit after
>>getting it from TTree::GetListOfFriends.
>>
>>For example you could extract (Remove) from it, TreeA,
>>TreeB, TreeC etc ... and add them to the list of friends
>>of TTreeA.
>>
>>Cheers,
>>Philippe.
>>
>>-----Original Message-----
>>From: owner-roottalk@pcroot.cern.ch
>>[mailto:owner-roottalk@pcroot.cern.ch]On Behalf Of cstrato
>>Sent: Tuesday, April 13, 2004 1:00 PM
>>To: Rene Brun
>>Cc: roottalk@pcroot.cern.ch
>>Subject: Re: [ROOT] How to separate tree friends
>>
>>
>>Dear Rene
>>
>>Thank you, but this is not what I want:
>>I have a method:
>> myclass-AddTrees("treename", "filename", "group")
>>where the user can add trees from different root files.
>>These trees are stored as friends to the first tree fTree.
>>
>>fTree is then passed to different methods, where I would
>>like to separate these trees based on their "groups",
>>and create e.g. two trees with friends for:
>>"group1": fTree("Tree1") with friends Tree2, Tree3, Tree4
>>"group2": atree("TreeA") with friends TreeB, TreeC
>>(These separate tree groups are then again passed to
>>different methods.)
>>
>>Best regards
>>Christian
>>
>>
>>Rene Brun wrote:
>>
>>
>>>Hi Christian,
>>>
>>>As I am not sure to understand your question (or what you want to do),
>>>I can only give a naive answer
>>>
>>> fTree = (TTree*)gDirectory->Get("Tree1");
>>> fTree->AddFriend("Tree2", "file2.root");
>>> fTree->AddFriend("Tree3", "file3.root");
>>> fTree->AddFriend("Tree4", "file4.root");
>>>
>>> aTree = (TTree*)gDirectory->Get("TreeA");
>>> aTree->AddFriend("TreeB", "fileB.root");
>>> aTree->AddFriend("TreeC", "fileC.root");
>>>
>>>Rene Brun
>>>
>>>
>>>cstrato wrote:
>>>
>>>
>>>
>>>>Dear Rooters
>>>>
>>>>Suppose that I have a tree with following friends:
>>>> fTree = (TTree*)gDirectory->Get("Tree1");
>>>> fTree->AddFriend("Tree2", "file2.root");
>>>> fTree->AddFriend("Tree3", "file3.root");
>>>> fTree->AddFriend("TreeA", "fileA.root");
>>>> fTree->AddFriend("Tree4", "file4.root");
>>>> fTree->AddFriend("TreeB", "fileB.root");
>>>> fTree->AddFriend("TreeC", "fileC.root");
>>>>
>>>>How can I separate fTree into the following two treefriends:
>>>>1, fTree("Tree1") with friends Tree2, Tree3, Tree4
>>>>2, aTree("TreeA") with friends TreeB, TreeC
>>>>
>>>>Thank you in advance for your help.
>>>>
>>>>Best regards
>>>>Christian
>>>>-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
>>>>C.h.r.i.s.t.i.a.n. .S.t.r.a.t.o.w.a
>>>>V.i.e.n.n.a. .A.u.s.t.r.i.a
>>>>-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
>
>
>>
>
>
>
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