STL container splitting in TTree construction

[patrizioconsole]

Dear all,

concerning ttree constructions available, I am considering the possibility to configure Branch using STL containers (mainly vector and array).

In case I have one of the following container:

• vector container;
• array <T,n> container;
  I compared cases of type ttree.branch(“branchname”, &container, “myVar[n]/T”) in which each row is provided with n data of type T, with the case of type ttree.branch(“branchname”, &container, “x1/T:x2/T … :xn/T”) in which each row is filled with n columns corresponding to n elements of container.

In addition I wanted to compare with a construction of the type: tree.Branch( branchname, STLcollection, buffsize, splitlevel);
If I write code like this: ttree.Branch(“branchname”, &container) it does not split and it is equal to ttree.branch(“branchname”, &container, “myVar[n]/T”). Here splitlevel = 1 by default. It does not change even if I try split>1

I would like to know how to perform splitting like ttree.branch(“branchname”, &container, “x1/T:x2/T … :xn/T”) with construction like tree.Branch( branchname, STLcollection, buffsize, splitlevel)

Thank you all in advance
Best Regards

[Danilo]

Hi Patrizio,

Thanks for the post and welcome to the ROOT Community!

Why not writing your x_i’s in individual branches, which are then automatically split?

Best,
D

[patrizioconsole]

Thank you Danilo for your prompt response.
I understand the solution you propose.

My question was in fact to know more about the chance in splitting STL containers in ttrees.

I am wondering if a STL container can be split only by means of dictionary generation of the object like in the TObject derived class case.

In addition I am asking the meaning of the “splitlevel” parameter: through examples I cannot exactly understand if it means the amount of columns from a given TObject or STL container or if it means a nesting level of the quantity per se.

Thank you again and best regards