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

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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

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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

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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 (*)