@date
@brief HLT examples and tutorial. */
-/** @defgroup alihlt_tutorial HLT examples and tutorial
- @brief HLT examples and tutorial
+/**
+@defgroup alihlt_tutorial HLT examples and tutorial
- A description will follow ...
-*/
+-# @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
+
+<br>
+<br>
+@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.
+<pre>
+{
+ AliHLTSystem gHLT;
+ gHLT.LoadComponentLibraries("libAliHLTUtil.so");
+}
+</pre>
+
+<br>
+@subsection tut_dummy_chain Example: Running a dummy chain
+The simplest chain consists of a publisher component, a processor
+and a data sink. The AliHLTDummyComponent is a sample component
+which just copies a fraction of the input data to the output.
+You can run the following macro from the AliRoot promt.
+<pre>
+{
+ 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();
+}
+</pre>
+@note You have to specify a real file name instead of \em some-data.dat
+
+<br>
+@subsection tut_tpc_sector Example: One sector of the TPC
+This example builds an analysis chain for TPC sector 0. It works on
+simulated data and assumes the ddl files to be present in the current
+directory.
+<pre>
+{
+ 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();
+}
+</pre>
+
+@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 <br>
+ @ref AliHLTAgentSample for a sample implementation
+
+@subsection tut_reconstruction_sample The sample library
+The libAliHLTSample library provides examples how to implement the
+library agent (@ref AliHLTAgentSample), how to add configurations and
+define HLT chains for reconstruction.
+
+The sample library is not part of the default libraries loaded by the
+HLT steering during reconstruction. The example can be run by the
+following macro in AliRoot (provided you have a simulated event in the
+current directory):
+<pre>
+{
+ 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();
+}
+</pre>
+
+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 <br>
+ This chain illustrates how data can be published from the AliRunLoader
+ in order to be processed by another component (not in the sample chain).
+ Finally, the @ref AliHLTSampleOfflineSinkComponent is component which is
+ the backend and has again the AliRoot structures.
+ - @ref AliHLTLoaderPublisherComponent
+ - @ref AliHLTSampleOfflineSinkComponent
+
+In the same way any other component library can be integrated into the
+AliRoot reconstruction.
+
+ */
/* note pad
git://git.uio.no / u / mrichter / AliRoot.git / blobdiff