offline calibration
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Offline Weekly Meeting, 24th April 2009C. Cheshkov & C. Zampolli
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 '09 C. Cheshkov & C. Zampolli 2
ALICE Off Weekly Apr '09 C. Cheshkov & C. Zampolli 3
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
ITS TRD ...
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 '09 C. Cheshkov & C. Zampolli 4
ALICE Off Weekly Apr '09 C. Cheshkov & C. Zampolli 5
Calibration/Alignment train of AliAnalysisTasks
reconstruction
Chunk i
ESD-Friends iESD i
ITS
TRD ...
ESD Friends i
ITS TRD ...
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!
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 '09 C. Cheshkov & C. Zampolli 6
Merging/Analysis procedure to produce a final file
ALICE Off Weekly Apr '09 C. Cheshkov & C. Zampolli 7
ESD Friends 0
ITS TRD ...
0......i... ...
N.B.: the wagons are the calibration objects written (in the ESD friends) before!
OCDB Updating
ESD Friends...
ITS TRD ...
ESD Friends i
ITS TRD ...
ESD Friends i+1
ITS TRD ...
ESD Friends...
ITS TRD ...
ESD 0 ESD ... ESD i ESD i+1 ESD ...
AOD 0 AOD... AOD i AOD i+1 AOD ...
auto
mat
ical
ly
The expert...
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 '09 C. Cheshkov & C. Zampolli 8
ESD friends should be modified in order to fit the new schema
Become independent from ESDs friend treeReduction 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 '09 C. Cheshkov & C. Zampolli 9
Core Offline:Fix the ESD FriendsMods 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 '09 C. Cheshkov & C. Zampolli 10
ALICE Off Weekly Apr '09 C. Cheshkov & C. Zampolli 11
ALICE Off Weekly Apr '09 C. Cheshkov & C. Zampolli 12
ALICE Off Weekly Apr '09 C. Cheshkov & C. Zampolli 13
Calibration/Alignment train
reconstruction
Chunk 0 Chunk 1 Chunk 2 Chunk 3
ESD 0 ESD 1 ESD 2 ESD 3
Cal/Alig data 0
Cal/Alig data 1
Cal/Alig data 2
Cal/Aligdata
3
Cal/Alig obj run in AliEn
(*) analogous to the existing merging procedure for ESD tags
Merging procedure (*)
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