sPHENIX tracking discussion

[Christof Roland <christof.roland AT cern.ch>]

Hi Everybody, 

The 1 hour field prining exercise turned into a two day project, as usual.
the good news is the memory profile using the pruned field is consistently 
below 4GB for 1000 events.

Some observations:
ACTS insiste on a cube field map. Cutting is to a cylinder shape gives an 
exceptions throw and job termination.
/phenix/u/bogui/data/Field/sphenix3dtrackingmapxyz.root is now the field in 
|x,y,z| <110cm i.e 6% of the original field volume.

We have setterrs for the field name and path in the code, but they are 
largely ignored and thee flied used is hardwired in the code. 
We may want to fix this. 

The SimpleKFProp and CASeeder still load the big map from the node tree using 
PHFieldUtility. 
I dont see an easy interface in PHFieldUtility to read a map from file. We 
may want to change this. 
CASeeding and KFProp land a separate fieldmap. If we switch this to the ACTS 
interface we could save 
another 0.5 - 0.75 GB of memory. 

Cheers

    Christof