2. Pavel Nevski STAR simulations and ROOT GSTAR root interface

3. Pavel Nevski GSTAR n STAR simulation framework since 96 –has a hierarchical design to clearly separate user code from G3 implementation details (Rene Brun, PN 1994) –has improved memory management »elastic ZEBRA »no limits on number of tracks, vertices, hits etc (apart from physical memory limits) –has a built-in database interface

4. Pavel Nevski STAR geometry n Formalized description in specification language, including hits and DB access n Many developers, very detail geometry (almost 2,000 different volumes) n Altogether less then 8000 lines including field parameterization, easy to read n No step routine is needed in most of the detectors, no “if statement” problem

5. Pavel Nevski GSTAR performance n Fast enough - 30 min/10,000 particles, with a general 1 MeV cuts n Calorimeter cuts tuned with test beam date down to 50 KeV n Interfaced to all event generators n Robust and well debugged production tool

6. Pavel Nevski So what do we want more? n We do want more ! –Flexible, expandable access to geometry objects from reconstruction program –Modern visualization and navigation –Access to hits from a C++ code as if they were normal C++ objects –fun, and even more fun n Well, we decided to grow ROOTs

7. Pavel Nevski Missing elements n Initially missing elements –Geometry navigator - trivial –Geometry decoder - not so trivial, but feasible –Volumes and positions separately - TVolume –Volumes as position container - TDataset –Hit navigator - trivial –Hit presenter - StGeantHits

8. Pavel Nevski G3 geometry model TDataset TVolume TVolumePosition list TVolumeView TShape StGeant TNode TVolumeView ctor

9. Pavel Nevski View as in G3

10. Pavel Nevski OpenGL viewer

11. Pavel Nevski Geant Hit Access Class class TPoints3DABC (from ROOT G3D) StGeantHits3D StGeantHits()... GetNextHit(Int_t indx) aghitget() aghitset()

12. Pavel Nevski

13. Conclusions Conclusions n Now we have all this done and working n what do we want more ? –TDataset ? Light named list of TDatasets –TVolume, TVolumeView, TVolumePosition as functional G3 analogs –and fun, even more fun