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This document outlines the requirements for the BES III offline and EF selection software, including framework architecture, algorithm specifications, framework utilities, language support, parallel processing, reconstruction algorithms, event filtering, running in the offline environment, physics analysis, Belle and Gaudi framework, and data management.
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General requirements for BES III offline & EF selection software Weidong Li
Requirements on the framework • Framework architecture: flexibility, simplicity and robustness • Modular structure and dynamically loading software components at run-time • Control of data processing • Allow to specify a sequence of algorithms • Execution of algorithm might depend on the physics signature of each event • Capable of specifying the configuration for adjustable parameters e.g. through JobOption file • Framework utilities: histogram service, messaging service, particle property service, timing service, input/output service, etc. • Independent of the underlying database or I/O technology. • Support multiple languages, Fortran and C++ • Support parallel processing at least in event level BES III Software Meeting
requirements on reconstruction algorithms • The algorithm should be designed with the goal of modular structure. Break down a major reconstruction task into a reasonable number of components. • Algorithms should remain unchanged whatever is the source of the data they are running on: EF data, offline data, simulation data, test-beam data. • Any parameters that an algorithm has should be available by user and should be configurable using a standard method. • For Monte-Carlo events, navigation from reconstructed data to Monte-Carlo data should be easy. • The correct calibration constants should be automatically picked. BES III Software Meeting
Requirements for Event Filter Selection Software (EFSSW) • Fast rejection to avoid unnecessary processing and to minimize the average decision latency. • Be able to change the selection strategy without rebuilding the software. • Both seeded and unseeded reconstructions should be supported. • Should be possible to specify a pre-scale factor for certain physics events like Bhabha or dimuon events. • Forced to accept a small fraction of events which otherwise would not pass for monitoring purpose. BES III Software Meeting
Requirements for EFSSW (2) • EFSSW algorithm should be thread-safed for processing events in parallel threads. • The interface between the framework control and EF algorithms is desired to be independent of running environment (offline or online). BES III Software Meeting
Running EFSSW in the offline environment • Development, testing and verification of EFSSW components • Determination and tuning of the performance in terms of selection efficiency, execution time and event rates based on simulation • Validation of the results and performance of the online system • Study trigger efficiency, acceptance and biases once real data are available BES III Software Meeting
Requirements for Physics analysis • Be able to produce and save persistently histograms and ntuples for later analysis using a separate tool like PAW • be able to use any reconstruction routines in the analysis environment • Existing legacy FORTRAN code should be supported • Telesis • Particle selection and identification • Secondary vertex finding • dE/dx correction • single eventdisplay BES III Software Meeting
Belle and Gaudi framework (1) • Gaudi architecture separates date from algorithmic code and provides standard software components for specialization: • DataObject • Algorithm • Service • Tool • Converter • Control of data processing • Path in Belle: the execution of modules is determined by Path and the conditional branch to another path is also supported. • Gaudi supports algorithm sequences, filters and branches BES III Software Meeting
Diagram for algorithm sequences and branches BES III Software Meeting
Belle and Gaudi framework (2) • Data management • Integral data management based on Panther (Belle) • Belongs to blackboard family (Gaudi) • Gaudi supports • Objectivity/DB • Microsoft Access • MySQL • ORACLE • Gaudi supports muti-threaded application BES III Software Meeting
Conclusions and open issue • The current BESF framework is in pretty good shape and should be regarded as the baseline solution for offline software. • But there are still difficulties to plug the offline algorithms in the online EF dataflow framework. • Shall we keep the choice of underlying framework open and make an effort to evaluate the feasibility of adopting Gaudi? BES III Software Meeting