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• <nop>Tier0AlignmentTutorial
• Introduction
• Flow of alignment iteration

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Introduction

This article describes a basic alignment iteration derivation using most modern platforms in early 2017, i.e.

• Athena release 21 (release 21.0.8)
• CMake
• Git ( atlas-idalignment/athena)
• The dynamic alignment scheme
• Smart batch iterator ( pdf slide)

Flow of alignment iteration

The alignment iteration process has two major jobOption steps: accumulation and solving. As a subsidiary (but important) process, Merging of monitoring data also runs.

• Accumulation is a process to reconstruct tracks usually starting from RAW data, and creates the chi-square matrix elements of the corresponding data, refferred to as AlignmentTFile.root. The number of jobs is equal or the same order as the number of input files.
• Solving is a process to concatenate all produced AlignmentTFile.root by the subjob, and calculate the alignment constants. The main output data is mycool.db and Iter?_AlignmentConstants.root, and some text dump of alignment processes (e.g. alignlogfile.txt). The number of jobs is 1.
• Merging is a process to do DQ histogram merging after all accumulation subjobs are done for each iteration. Once merging for all iterations is done, a simple script to generate comparison histograms (of e.g. residual distributions) over iterations is processed to generate monitoring plot files. The number of jobs is also 1.

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-- JavierJimenezPena - 2018-01-25