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FRED Tutorial

FRED is an event display program that supports HepRep, a protocol for communicating
events in high energy physics experiments. HepRep represent an event as two hierarchies:

  • Types (with father-child relationships, e.g., a Track, a Hit, or a Geometry Volume).
  • Instances (actual objects of a given Type).

Two aspects of HepRep implemented in FRED are:

  • Corba middleware - used to create a server-client framework.
  • XML - used for persistency of events and fast exchange of HepRep hierarchies.

Note: The GLAST Gaudi service can output events in HepRep xml files.

Refer to the Gleam Data Flow Diagram and observe that whatever can be put in the
Gaudi Transient Data Store (Gaudi TDS) can also be served as a HepRep, either as
an xml or as a Corba object.

Install GlastRelease and Download Example Files

  1. Using the Glast Software Installer, download the binaries and external libraries for the latest tagged version of GlastRelease to your work area (e.g., C:\glast\ and C:\glast\extlib).

Be sure your GLAST_EXT environmental variable path points to your extlib directory.)

Note: If you are a Linux user and prefer using a command line installer instead of a GUI, see Linux Command Line Installer.

  1. Download the following example files to your work directory (e.g., C:\glast\work):

Modify Job Options

  1. Locate the readAndDisplay.txt job options file located in the following directory:

c:\glast\GlastRelease-vXXrXX\Gleam\vXrXpXX\src\

  1. Open the readAndDisplay.txt file in your text editor.
  1. In the readAndDisplay.txt file, scroll down and comment out any lines pointing to "mc" or "relation".

For example, at the time this was written, four lines were commented out "//" as shown in [1] thru [4] of this example of a readAndDisplay.txt job options file.

  1. Now, modify the following two lines:

digiRootReaderAlg.digiRootFileList = { "$(ROOTTESTDATAROOT)/data/default/digi.root" } ;
reconRootReaderAlg.reconRootFileList = { "$(ROOTTESTDATAROOT)/data/default/recon.root" } ;

so that they point to the example files downloaded in step 2, above.

For example, if you saved those files to your c:\glast\work directory, you would modify them as shown in lines [5] and [6] of the example of a readAndDisplay.txt job options file.

Launch Gleam

  1. From the command line prompt, go to the gleam\bin directory by issuing the following command:

    cd c:\glast\packages\GlastRelease-vXXrXX\bin\

  1. Then run Gleam.vb and specify the readAndDisplay.txt job option file by issuing the following command:

    Gleam.vbs ..\Gleam\vXrXpX\src\readAndDisplay.txt

Gleam will execute and, when it completes, a message similar to the following will be displayed ...

and FRED will launch automatically:

Explore Options

   

The buttons shown above respectively enable you to Stop (the session), Refresh (the images), and select the Back (previous) Event or the Next Event. The data entry box enables you to view a specific event by entering either the event index (e.g., 2), or the ID number and then: Enter key. Clicking on the button to the right will launch the start/stop slide show GUI.

Note: At the time this was written, the "Back Event" button was inoperative.)

Buttons to the right (top to bottom) allow you to open a new 3D view, or view: an xy, xz, or an yz projection. The next button displays 4 views, and the bottom button allows you to render the 3D views using the z buffer.

 

After you have selected an image by clicking on it, the 3D Controls shown below enable you to rotate and/or zoom in and out.

Tip: You can also click and hold on an image to rotate it, or simply click on one of the axis buttons described above to view an image from a different angle.

 
  The buttons shown at left allow you to take a snapshot of an image; launch a script dialog GUI, or launch the Fred GLAST Panel (which allows you to enter the Gaudi package setup, executable, and jobOptions file, or access a personal setup).
 
 
  The Views Controls and Logs buttons enable you to toggle between the 3D Controls pane and the Logs pane shown below.  
 
Right click on an image to launch the GUI shown at right.
Tip: To Change background color, launch the Color Dialog GUI shown below:
 
 

Then click on the eye-dropper button before selecting the color you wish to use.
   

HepRep Instance Tree

After selecting the HepRep Instance tree, you can click on an Event or GLAST-LAT component to display it in color:

Tip: Right click on the component (e.g., solarPanelCoreBox), to display the options GUI:

 


Owned by: Heather Kelly  
Last updated by: Chuck Patterson 11/16/2006