1. AliRoot status and PDC’04
P.Hristov
Monthly video-conference
February 06, 2004
CERN

2. Goals(
Determine readiness of the off-line framework for data processing
Validate the distributed computing model
PDC’2004:10% test of the final capacity
Complete chain used for trigger studies
Prototype of the analysis tools
Comparison with parameterized MC
Simulated RAW data
PDC’04 physics: hard probes (jets, heavy flavours) & pp physics

3. Physics Data Challenge'2004
Simulation: 10^5 Pb-Pb + 10^7 p-p 102 TB
450 KSI2K (~ tier-1 capacity) x 3 months
Distributed production, then data are shipped to CERN
Reconstruction: 5x10^6 Pb-Pb+10^7 p-p 187 TB
Reconstruction is shared between CERN & outside centres according to available resources
Data originate from CERN
Analysis: 5x10^6 Pb-Pb+10^7 p-p 13 TB
See

4. PDC’04 Strategy Part 1: underlying events
Distributed simulation, production of summable digits, digitization, clusterization, reconstruction, PID, and generation of ESD
Data transfer to CERN: kinematics, track references, summable digits (hits for some detectors)
Part 2: signal events & test of CERN as data source
Distributed simulation, production of summable digits, merging, digitization, clusterization, reconstruction, PID, generation of ESD
Part 3: distributed analysis

5. AliRoot status New tagged version v4-01-03 from today
Works with Root v and Geant3 v0-6 (Geant3 + Geom. Modeller )
Simulation (providing Config.C)
AliSimulation sim;
Sim.Run(# of events);
Reconstruction
AliReconstruction rec;
Rec.Run();

6. Simulation Configuration: exists for all signal classes
Geometry: OK for all the detectors, many overlaps and extrusions corrected (still some in ITS, TOF)
Hijing: fixed problems in the quenching, more reasonable distribution =>
Use Hijing with quenching and without additional energy dependence
Configuration: exists for all signal classes
AliEn JDL files: template exists

7. Summable digits, Digits, Merging
Ok for all detectors (if applicable)
AliVertexGenFile class to set the correct vertex in Config.C for the signal events (needs read access to the galice.root of the underlying event)
AliSimulation class used
AliSimulation sim;
sim.MergeWith(“../backgr/galice.root”,nSpB);
sim.Run(nSignal);

8. Clusters, Reconstruction, PID, ESD
Barrel detectors: OK
TRD reconstruction fixed
Parallel TPC tracking by default
ITS dE/dx PID fixed
ESD analysis template available
Calorimeters: PHOS – OK, EMCAL – ESD is still empty
MUON arm: OK, but has not been tested in a large production => potential problems
ESD: needs more users

9. Observations
NewIO: has to be simplified, more rigorous approach needed. Now one has too many opportunities => possibility for errors
Folders & Tasks: again strict discipline is needed (object ownership, etc.)
ESD: possibility to store intermediate results required (in progress)
More attention to simple things (new/delete, pointer initialization, etc.)

10. Conclusions AliRoot is ready for PDC’04 
Well tested simulation and generation of summable digits
Some problems still expected in the reconstruction (not all the code is stressed enough)
Possibility to incorporate additional features before the second part (signal generation)
Possibility to repeat the reconstruction of the underlying events

11. ToDo Estimation of CPU and storage needs for the signal classes
AliEn JDL files
Start set of tests with AliEn
Start the processing of the underlying events
Continue PDC04…