/************************************************************************
**
** ALICE HLT project
** Copyright (c) 2005
**
** This file is property of and copyright by the Experimental Nuclear
** Physics Group, Dep. of Physics and Technology
** University of Bergen, Norway, 2004
** This file has been written by Matthias Richter,
** Matthias.Richter@ift.uib.no
**
** Permission to use, copy, modify and distribute this software and its
** documentation strictly for non-commercial purposes is hereby granted
** without fee, provided that the above copyright notice appears in all
** copies and that both the copyright notice and this permission notice
** appear in the supporting documentation. The authors make no claims
** about the suitability of this software for any purpose. It is
** provided "as is" without express or implied warranty.
**
*************************************************************************/
/** @file tutorial.c
@author Matthias Richter
@date
@brief HLT examples and tutorial. */
/**
@defgroup alihlt_tutorial HLT examples and tutorial
-# @ref tut_hltsystem
-# @ref tut_load_libraries
-# @ref tut_dummy_chain
-# @ref tut_tpc_sector
-# @ref tut_reconstruction
-# @ref tut_module_agent
-# @ref tut_reconstruction_sample
@section tut_hltsystem Running Components in the HLT System
@subsection tut_load_libraries Library setup
Component libraries must be loader via the AliHLTComponentHandler
or AliHLTSystem::LoadComponentLibraries. You can run the following
macro from the AliRoot promt.
{ AliHLTSystem gHLT; gHLT.LoadComponentLibraries("libAliHLTUtil.so"); }
{ AliHLTSystem gHLT; gHLT.LoadComponentLibraries("libAliHLTUtil.so libAliHLTSample.so"); AliHLTConfiguration publisher("fp1", "FilePublisher", NULL, "-datafile some-data.dat"); AliHLTConfiguration copy("cp", "Dummy", "fp1", "output_percentage 80"); AliHLTConfiguration sink1("sink1", "FileWriter", "cp", NULL); gHLT.BuildTaskList(&sink1); gHLT.Run(); }@note You have to specify a real file name instead of \em some-data.dat
{ AliHLTSystem gHLT; // load the component library gHLT.LoadComponentLibraries("libAliHLTUtil.so libAliHLTTPC.so"); // data source components AliHLTConfiguration fp0("fp0", "FilePublisher", NULL, "-datafile TPC_768.ddl -datatype DDL_RWPK 'TPC '" "-dataspec 0x00000000"); AliHLTConfiguration fp1("fp1", "FilePublisher", NULL, "-datafile TPC_769.ddl -datatype DDL_RWPK 'TPC '" "-dataspec 0x00000101"); AliHLTConfiguration fp2("fp2", "FilePublisher", NULL, "-datafile TPC_840.ddl -datatype DDL_RWPK 'TPC '" "-dataspec 0x00000202"); AliHLTConfiguration fp3("fp3", "FilePublisher", NULL, "-datafile TPC_841.ddl -datatype DDL_RWPK 'TPC '" "-dataspec 0x00000303"); AliHLTConfiguration fp4("fp4", "FilePublisher", NULL, "-datafile TPC_842.ddl -datatype DDL_RWPK 'TPC '" "-dataspec 0x00000404"); AliHLTConfiguration fp5("fp5", "FilePublisher", NULL, "-datafile TPC_843.ddl -datatype DDL_RWPK 'TPC '" "-dataspec 0x00000505"); // cluster finders AliHLTConfiguration cf0("cf0", "TPCClusterFinderPacked", "fp0", "pp-run rawreadermode 4 timebins 446"); AliHLTConfiguration cf1("cf1", "TPCClusterFinderPacked", "fp1", "pp-run rawreadermode 4 timebins 446"); AliHLTConfiguration cf2("cf2", "TPCClusterFinderPacked", "fp2", "pp-run rawreadermode 4 timebins 446"); AliHLTConfiguration cf3("cf3", "TPCClusterFinderPacked", "fp3", "pp-run rawreadermode 4 timebins 446"); AliHLTConfiguration cf4("cf4", "TPCClusterFinderPacked", "fp4", "pp-run rawreadermode 4 timebins 446"); AliHLTConfiguration cf5("cf5", "TPCClusterFinderPacked", "fp5", "pp-run rawreadermode 4 timebins 446"); // tracker AliHLTConfiguration tracker("tracker", "TPCSliceTracker", "cf0 cf1 cf2 cf3 cf4 cf5", "pp-run bfield 0.5"); // the data sink component AliHLTConfiguration writer("writer", "TPCEsdWriter", "tracker", "-datafile AliESDs.root"); gHLT.BuildTaskList(&writer); gHLT.Run(); }@section tut_reconstruction AliRoot reconstruction The HLT analysis components can be run either in the AliRoot reconstruction or the HLT online framework. The integration into the AliRoot reconstruction works via the @ref AliHLTReconstructor plugin. The intention is to run HLT analysis chains in AliRoot in the same way as in the online framework, i.e. the full components are run also from the offline framework rather than just the algorithm hooked on by a special interface class. By this one achieves the highest possible compatibility. We think of the HLT as a 'black box' with data input and output. In addition there is access to calibration data from OCDB (or the local HLT copy HCDB). All components can only work on the data they get as input. As the different detector algorithms/components will run in separated processes and even on different machines, no data exchange is possible via global data structures and variables possible. The AliRoot reconstruction consists mainly of three steps: -# local event reconstruction: this is usually the place for digit/raw data conversion to clusters/space points. All the events are processed at once. If HLT analysis chain are executed in the local event reconstruction, the chain must contain an output recorder as the ESD is filled on an event by event basis and the corresponding method called later. -# event reconstruction: this is the reconstruction on an event by event basis. Immediately after the reconstruction, the FillESD method is called. -# ESD fill: the reconstructed event is written to the ESD. @subsection tut_module_agent The Module Agent Each component library has to implement a module agent in order to be hooked up to the AliRoot reconstruction system. The agent defines the features of the libraries and the configurations to be run during the different steps of the reconstruction. The agent - can register all components of the library. This is an alternative to the component registration via global objects (see @ref alihltcomponent-handling). - registers HLT configurations (see @ref AliHLTConfiguration) - specifies the configurations to be run - specifies additional component libraries required to run the configurations. Finally, one global object of the module agent has to be specified in the source code. All registration and integration into the HLT system is carried out automatically. @see @ref AliHLTModuleAgent for the interface description
{ AliReconstruction rec; // the reconstruction instance rec.SetRunLocalReconstruction("HLT"); // run local rec only for HLT rec.SetRunTracking(""); // switch off tracking rec.SetOption("HLT", "libAliHLTSample.so"); rec.Run(); }The agent defines the following chains: -# a simple data copying consisting of a - @ref AliHLTFilePublisher publishes some data generated before in /tmp - @ref AliHLTDummyComponent copies a fraction of the incoming data - @ref AliHLTFileWriter writes the data input to a file -# digit publishing from the TPCloader