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Implementation of the ATLAS Run 2 event data model

During the 2013--2014 shutdown of the Large Hadron Collider, ATLAS switched to a new event data model for analysis, called the xAOD. A key feature of this model is the separation of the object data from the objects themselves (the `auxiliary store'). Rather being stored as member variables of t...

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Autor principal: Snyder, Scott
Lenguaje:eng
Publicado: 2015
Materias:
Acceso en línea:http://cds.cern.ch/record/2007523
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author Snyder, Scott
author_facet Snyder, Scott
author_sort Snyder, Scott
collection CERN
description During the 2013--2014 shutdown of the Large Hadron Collider, ATLAS switched to a new event data model for analysis, called the xAOD. A key feature of this model is the separation of the object data from the objects themselves (the `auxiliary store'). Rather being stored as member variables of the analysis classes, all object data are stored separately, as vectors of simple values. Thus, the data are stored in a `structure of arrays' format, while the user still can access it as an `array of structures'. This organization allows for on-demand partial reading of objects, the selective removal of object properties, and the addition of arbitrary user-defined properties in a uniform manner. It also improves performance by increasing the locality of memory references in typical analysis code. The resulting data structures can be written to ROOT files with data properties represented as simple ROOT tree branches. This talk will focus on the design and implementation of the auxiliary store and its interaction with ROOT.
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institution Organización Europea para la Investigación Nuclear
language eng
publishDate 2015
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spelling cern-20075232019-09-30T06:29:59Zhttp://cds.cern.ch/record/2007523engSnyder, ScottImplementation of the ATLAS Run 2 event data modelParticle Physics - ExperimentDuring the 2013--2014 shutdown of the Large Hadron Collider, ATLAS switched to a new event data model for analysis, called the xAOD. A key feature of this model is the separation of the object data from the objects themselves (the `auxiliary store'). Rather being stored as member variables of the analysis classes, all object data are stored separately, as vectors of simple values. Thus, the data are stored in a `structure of arrays' format, while the user still can access it as an `array of structures'. This organization allows for on-demand partial reading of objects, the selective removal of object properties, and the addition of arbitrary user-defined properties in a uniform manner. It also improves performance by increasing the locality of memory references in typical analysis code. The resulting data structures can be written to ROOT files with data properties represented as simple ROOT tree branches. This talk will focus on the design and implementation of the auxiliary store and its interaction with ROOT.ATL-SOFT-SLIDE-2015-161oai:cds.cern.ch:20075232015-04-09
spellingShingle Particle Physics - Experiment
Snyder, Scott
Implementation of the ATLAS Run 2 event data model
title Implementation of the ATLAS Run 2 event data model
title_full Implementation of the ATLAS Run 2 event data model
title_fullStr Implementation of the ATLAS Run 2 event data model
title_full_unstemmed Implementation of the ATLAS Run 2 event data model
title_short Implementation of the ATLAS Run 2 event data model
title_sort implementation of the atlas run 2 event data model
topic Particle Physics - Experiment
url http://cds.cern.ch/record/2007523
work_keys_str_mv AT snyderscott implementationoftheatlasrun2eventdatamodel