Manuel Sanchez Garcia wrote: > > Hello Rooters, > > My question is the following: > Is there an easy way to have a tree with many branches, each of them > having subbranches and so on..?. For example i would like to have one > branch per element in an array.... > > At the moment i am doing that by creating the tree by hand. I mean, > i take a pointer to a branch (let's say b) and add subbranches using: > b->GetListOfBranches()->Add(newBranch) > The automatic split algorithm in TTree::Branch creates one branch for each data member of the top level object. - If the data member is itself an object, in turn, new branches will be created for each member of the sub-object. - If the data member is a pointer to an object, this object will be serialized in its branch buffer. - If the data member is a pointer to a TClonesArray, then each data member of the class referenced by the TClonesArray will also go to a separate branch. An example is given in the Root distribution kit $ROOTSYS/test/Event where all cases above are used. You can create yourself your own branch structure. Last November, we announced the ATLFast package (Atlas fast MonteCarlo). This package is described at URL: http://root.cern.ch/root/Atlfast.html It is a good illustration of a program build with modules (Makers). Each Maker generates objects or TClonesArrays of objects. We strongly encourage Root users in the process of building an event Tree structure to look at the technique used in ATLFast. In particular, look at the way we save the main object ATLfast (see ATLFast::Streamer and ATLFMaker::Streamer). Rene Brun
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