Re: Strange behavior of TBranch::Fill

For me each branch is a standalone object, in fact I could create several trees, each of them containing one single branch!

In my application, each branch is containing the time evolution of a certain quantity related to a certain physical object. I have many different objects to monitor (that's the reason why I have many branches) but they are not all evolving at the same speed. I mean, there are objects updated every once in a while, and other evolving rather slowly (and that's the reason of the different number of entries). I hope it is clear now.

That's it! I believe that the easiest workaround is to use one TTree for each object.

thanks,

Antonio

-- 
Antonio Bulgheroni, PhD

Computers have a lot in common with air conditioners:
Once you open WINDOWS, they stop working properly.

On 7/19/07, Philippe Canal <pcanal_at_fnal.gov> wrote:


>

> > but they for sure have different number of entries, at least this is

> what I would like to have!

>

> Hence, my real question :) Why?  What concept are you capturing in this

> way?  Or in other words,

> once this tree is written how are you going to use it?

>

> If I can understand your motivation, I can help you find the best solution

> :)

>

> Cheers,

> Philippe.

>

>  ------------------------------

> *From:* Antonio Bulgheroni [mailto:antonio.bulgheroni_at_gmail.com]

> *Sent:* Thursday, July 19, 2007 7:23 AM

> *To:* Philippe Canal

> *Cc:* ROOT Talk

> *Subject:* Re: [ROOT] Strange behavior of TBranch::Fill

>

> Dear Philippe,

>    thanks for your reply.

>

> The problem is that in my case I really don't need to have all branches

> filled with the same number of entries. The example I sent around was

> oversimplified: in my real life case I have several branches, none of them

> is empty of course, but they for sure have different number of entries, at

> least this is what I would like to have!

>

> I will try to find another solution....

>

> thanks again!

>

> Cheers,

> Antonio

>

> --

> Antonio Bulgheroni, PhD

>

> Computers have a lot in common with air conditioners:

> Once you open WINDOWS, they stop working properly.

>

> On 7/19/07, Philippe Canal <pcanal_at_fnal.gov> wrote:

> >

> > Hi Antonio,

> >

> > This is the expected behavior of your code.  In you branch->Fill case,

> > the

> > tree is never informed that it has any entries ... and hence the tools

> > (TBrowser, etc..) thinks the tree is empty.  For most of the tools, it

> > is

> > important that each branch to be filled with the

> > same amount of entries (because they match entries by their sequential

> > order

> > in the branch).

> >

> > You can 'fix' a TTree after being filled by your branch->Fill method by

> > calling 'tree->SetEntries()' but it will complain if one of the branch

> > has

> > less entries than the other.

> >

> > You can also use SetBranchStatus(brname,0) and tree->Fill to prevent the

> > filling of individual branches.

> >

> > > I don't need (and don't want) to fill all branches,but I would like to

> > indivually fill only branches I'm interested in.

> >

> > Why?  What do you want to represent with the 'empty' branch?  Wouldn't

> > it be

> > better to __not__ add the branch to the TTree.

> >

> > You may want to consider replacing the

> >       TBranch * branch2 = tree->Branch("calib2.", &calib2, 8000, 1);

> > by

> >     vector<Calib> *vec;

> >       TBranch * branch2 = tree->Branch("calib2.", &vec, 8000, 1);

> > where the vector would be filled or not.

> >

> > You may also want to replace both branch with a single vector with one

> > of

> > more object in it,

> > depending on the semantic.

> >

> > Cheers,

> > Philippe.

> >

> > ________________________________

> >

> > From: owner-roottalk_at_pcroot.cern.ch [mailto:owner-roottalk_at_pcroot.cern.ch

> > ]

> > On Behalf Of Antonio Bulgheroni

> > Sent: Thursday, July 19, 2007 1:55 AM

> > To: ROOT Talk

> > Subject: [ROOT] Strange behavior of TBranch::Fill

> >

> >

> > Dear ROOTers,

> >

> > I would like to report you the strange behavior of the TBranch::Fill

> > compared to the TTree::Fill. In my real life case I have a TTree with

> > several branches; I don't need (and don't want) to fill all branches,but

> > I

> > would like to indivually fill only branches I'm interested in. For this

> > reason, I'm getting from the TTree the branch I need, I'm setting the

> > address of the TBranch to a local variable and finally I call

> > TBranch::Fill(). Everything is working fine but the tree browser, indeed

> > if

> > I browse the TTree and double click on a leaf instead of drawing the

> > leaf

> > content on a canvas, nothing is happening.

> >

> > I discovered that if I replace the TBranch::Fill call with a

> > TTree::Fill,

> > the tree broswer is working again, but every time I have

> > all branches filled. Here attached a simplified example, calib.h and

> > calib.cxx contain the class defining the branch content, and test.C a

> > simple

> > macro to fill in a tree using in one case TBranch::Fill and in the other

> >

> > TTree::Fill.

> >

> > Is this the correct behavior? If so, is there any workaround to have

> > branches browsable and individually fillable? I played a bit with the

> > branch status, but unsuccessfully.

> >

> > Thanks in advance.

> >

> > Cheers,

> > Antonio

> >

> > Tested on the following configurations:

> >

> > ROOT 5.15/08 + Linux (Fedora 7) +  g++  4.1.2

> > ROOT 5.13/04 + SLC 4 + g++  3.4.6

> > ROOT 5.10/00e + SLC 3

> > --

> > Antonio Bulgheroni, PhD

> >

> > Computers have a lot in common with air conditioners:

> > Once you open WINDOWS, they stop working properly.

> >

> >

>