What is row_wise_branch which is created only in MT mode?

I’m using Geant4.10.5.1.
When I run the example B4c in multi-thread mode and output to a root file, the columns of ntuple created in B4RunAction.cc are under row_wise_branch as below:

What is row_wise_branch?
It’s no problem for me. But if all columns are just under TTree like those in single-thread mode, it’s better for me.
It is possible?

And I’m implementing a Geant4 application based on B4c.
I added some columns of a vector.
The multi-thread mode also creates columns named “{name}_count” for columns of a vector named “{name}”.
What is this?

The meaning of the row_wise_branch is explained in the Application Developers Guide, see:

With the next Geant4 version, 10.6, a new merging mode will be added which will perform ntuple merging with preservation of rows with the additional branch in the output.

Best regards,

Hi Ivana,

Thank you for your reply!
The link is very helpful since I couldn’t find any documents about it.

Best regards,