Files
	TXXXAnalysis.cxx

	TXXXAnalysis.h

	TXXXControl.cxx

	TXXXControl.h

	TXXXEvent.cxx

	TXXXEvent.h

	TXXXProc.cxx

	TXXXProc.h

	XXXLinkDef.h

Detailed Description

This package contains a simple running 1 step Go4 analysis.

Rebuild the package by

make clean

make all

A test file is $GO4SYS/data/test.lmd

Analysis class

All classes are defined and declared in two files (*.h and *.cxx) In TXXXAnalysis the analysis step is created with the step factory and input and output parameters. Here the defaults are set concerning the event IO. Also parameter object of class TXXXControl is created.

The event filled: TXXXEvent The processor: TXXXProc

The factory created in TXXXAnalysis keeps all information about the step. The TXXXEvent contains the data members to be filled in TXXXProc from the input event (MBS 10,1). The Clear method must clear all these members (an array for each crate in the example). The analysis code is in the event processor TXXXProc. Members are histograms, conditions, and parameter pointers used in the event method Event. In the constructor of TXXXProc the histograms and conditions are created, and the pointers to the parameter objects (created in TXXXAnalysis) are retrieved. Function BuildEvent - called event by event - gets the output event pointer as argument (AnEvent). The input event pointer is retrieved from the framework. In the first part, data from the raw input MBS event are copied to the members of output event TXXXEvent. Two subevents (crate 1,2) are processed. Then the histograms are filled, the 2d one with polygon conditions.

Parameter class TXXXControl

This class has one member "fill" which is checked in TXXXProc->Event to fill histograms or not. The macro histofill.C is actually used to set filling on or off (when creating TXXXProc). You can modify histofill.C by editor. This is an example how parameter members can be modified by macros at runtime, independent from the autosave file settings.

Autosave file mechanism.

By default autosave is enabled in batch mode, disabled in GUI mode, and all objects are saved into this ROOT file at the end. At startup the autosave file is read and all objects are restored from that file. When TXXXAnalysis is created, the autosave file is not yet loaded. Therefore the objects created here are overwritten by the objects from autosave file (if any), except histograms. From GUI, objects are loaded from autosave file when Submit button is pressed. One can inspect the content of the auto save file with the Go4 GUI.

Run analysis.

Analysis can be started from the Go4 GUI or by command line:

go4analysis -file $GO4SYS/data/test.lmd
go4analysis -random
go4analysis -stream r3f-12

The events can be read from standard GSI lmd files or MBS or event servers. For each event the user event processor TXXXProc is called. This user event processor fills some histograms and an output event TXXXEvent (raw event) from the input event. The output events can optionally be stored in root files.

Creating a new class

Provide the definition and implementation files (.h and .cxx) Add class in Makefile and XXXLinkDef.h Then make all.

Adopt the example

Most probably you will change TXXXControl to keep useful parameters. Then you might change TXXXEvent to represent your event data. Keep the Clear method consistent with the data members! Then definitely you will change TXXXProc to create your histograms, conditions, pictures, and finally write your analysis function BuildEvent.

In TXXXAnalysis there are three more functions which eventually can be useful: UserPreLoop (called before event loop starts), UserEventFunc (called after TXXXProc->Event), UserPostLoop (called after event loop stopped).

Files