1. Offline Weekly Meeting, 24th April 2009 C. Cheshkov & C. Zampolli

2. Calibration and Alignment should always be AliAnalysisTasks Reuse of the existing Analysis framework All the calibration/align data will be stored in ESD/ESD Friends/AOD files No additional file No new Object invented ALICE Off Weekly Apr '09C. Cheshkov & C. Zampolli2

3. ALICE Off Weekly Apr '09C. Cheshkov & C. Zampolli3 Reconstruction (inside the event loop) Calibration/Alignment AliAnalysisTasks Chunk i ESD 0 Chunk 0...Chunk 1Chunk i+1Chunk i+2... Not necessarily AliAnalysisTasks, but useful like this (it can be run on files) Objects that scale with the n. of events! (branches of the tree for ESD friends) ESDFriends i ITSTRD...

4. Offline Calibration – as well as Alignment – could be organized as “calibration/alignment tasks” to be run during reconstruction: Within AliReconstruction, in the event loop Every detector providing its own task Every detector wagon should produce Calibration/Alignment data, to be stored in the ESD or ESD Friends (in branches) If filling ESD friend branhces, only a selected fraction of events will have the calib/align ESD friends branches filled ALICE Off Weekly Apr '09C. Cheshkov & C. Zampolli4

5. ALICE Off Weekly Apr '09C. Cheshkov & C. Zampolli5 Calibration/Alignment train of AliAnalysisTasks reconstruction Chunk i ESD-Friends i ESD i ITS TRD... ESD Friends i ITSTRD... Chunk 0...Chunk 1Chunk i+1Chunk i+2... N.B.: the wagons are the different tasks! Objects that do not scale with the n. of events!

6. Offline Calibration – as well as Alignment – could be organized as a “calibration/alignment train” to be run immediately after the reconstruction – in the same job, or in the same aliroot session: Every detector providing its own wagon Single loop over the events instead of once per detector calibration procedure Running on the Worker Node on local files  ESDFriend available Every detector wagon should produce Calibration/Alignment data in histogram-like format (not scaling with n. of events), to be stored in the ESD Friends (in folders) ALICE Off Weekly Apr '09C. Cheshkov & C. Zampolli6

7. Merging/Analysis procedure to produce a final file ALICE Off Weekly Apr '09C. Cheshkov & C. Zampolli7 ESD Friends 0 ITSTRD... 0......i...... N.B.: the wagons are the calibration objects written (in the ESD friends) before! OCDB Updating ESD Friends... ITSTRD... ESD Friends i ITSTRD... ESD Friends i+1 ITSTRD... ESD Friends... ITSTRD... ESD 0ESD...ESD iESD i+1ESD... AOD 0AOD...AOD iAOD i+1AOD... automatically The expert...

8. Merging the information coming from the different runs The procedure is a train, with the wagons being the various ESD/ ESD friends/ AOD files from the various runs Calculation of the calibration constants according to the result of the merging procedure  either manual or automatized ALICE Off Weekly Apr '09C. Cheshkov & C. Zampolli8

9. ESD friends should be modified in order to fit the new schema Become independent from ESDs  friend tree Reduction in size Every detector should evaluate the number and type of events needed and the size of data to be stored ESD friends file should be always kept, but with ESD friend objects saved only for the requested fraction of event ALICE Off Weekly Apr '09C. Cheshkov & C. Zampolli9

10. Core Offline: Fix the ESD Friends Mods in AliReconstruction The Detectors: Ask the detectors to evaluate number/type of events needed and size of data Ask the detectors to write their AliAnalysisTasks ALICE Off Weekly Apr '09C. Cheshkov & C. Zampolli10

11. ALICE Off Weekly Apr '09C. Cheshkov & C. Zampolli11

12. ALICE Off Weekly Apr '09C. Cheshkov & C. Zampolli12

13. ALICE Off Weekly Apr '09C. Cheshkov & C. Zampolli13 Calibration/Alignment train reconstruction Chunk 0Chunk 1Chunk 2Chunk 3 ESD 0ESD 1ESD 2ESD 3 Cal/Alig data 0 Cal/Alig data 1 Cal/Alig data 2 Cal/Alig data 3 Cal/Alig obj run in AliEn (*) analogous to the existing merging procedure for ESD tags Merging procedure (*) i-th Run j-th Run