Re: Trouble with trees

> see this note in TTree::Branch
> // Note that the TTree will assume that all the item are
> contiguous in memory.
> // On some platform, this is not always true of the member of a
> struct or a class,
> // due to padding and alignment. Sorting your data member in
> order of decreasing
> // sizeof usually leads to their being contiguous in memory.
>
> Using this old-style branch is less efficient than using a class in
> split mode. The compression level is less efficient and you are
> subject to these alignment problems.

Well trying to align them by putting doubles first and ints later didn't help either. But I have a temporary workaround by just using:

	for (Int_t i = 1; i < t->GetEntries(); i++) {
		t->GetEntry(i);
		cout << t->GetLeaf("s")->GetValue() << " ";
		cout << t->GetLeaf("mRel")->GetValue() << " ";
		cout << t->GetLeaf("sumpt")->GetValue() << " ";
		cout << t->GetLeaf("pt1")->GetValue() << " ";
		cout << t->GetLeaf("pt2")->GetValue() << " ";
		cout << t->GetLeaf("pt3")->GetValue() << " ";
		cout << t->GetLeaf("pt4")->GetValue() << " ";
		cout << t->GetLeaf("dRp")->GetValue() << " ";
		cout << t->GetLeaf("dRn")->GetValue() << " ";
		cout << t->GetLeaf("met")->GetValue() << " ";
		cout << t->GetLeaf("nTau")->GetValue() << " " << endl;		
	}

Event though that's extremely inefficient it works for now... But it would be still good to know how I can save/read the structure with that particular root version. Or should I remove the structure and go with 11 separate variables instead in 11 branches...

Mario Received on Wed Jul 08 2009 - 11:21:10 CEST