E907MC-DATA DRIVEN GEANT for the experiment E907

 

Rajendran Raja 

7/19/2002 3:34:15 PM

E907MC is a version of GEANT 3.21 that is data driven. The program contains no hard-coded geometry constants. The Geometry and Detectors systems are fed to the program usingRCP files that are structured text files. The main routine is called hanuman.F. The program works on SGI/UNIX and LINUX. The program is built using Makefiles. All fortran routines are in the style of CERNLIB (i.e. *.F). They can contain compile time switches and common blocks are introduced via the #include construction. 

··Geant Documentation

··  RCP files

··RCPE files

··Declaring RCP and RCPE files to the program

··Fortran Coding Standards

··Preparing your area

··Building the needed libraries

··Building and running the E907MC executable

··Library Linking Order and the lddum routines

··Analyzing and Playing Back events

GEANT Documentation

CERN program library provides GEANT 3.21 documentation in postscriptand HTML forms. We will assume that the user is familiar with GEANT principles and has read the GEANT manual. We will attempt to give hyperlinks to the appropriate GEANT subroutine documentation when warranted.

RCP files

RCP files are inherited from the D0 experiment Run I code. These are structured ASCII files that can be used to input data to programs in an orderly form. Fortran programs can read in variables from RCP files from any subroutine without use of common blocks. The constants are kept in ZEBRA banks and are made available to the user by means of a fast binary search among the bank contents. RCP files can handle all common data types, Integer *4, Character ,Real*4 and Logicals. The general format of the file is a variable name (up to 32 characters long) followed by a value. Character values are enclosed in single quotes. Exclamation point (!) signifies that the remainder of the line is a comment. In addition to single characters, one can also specify arrays of variables by the declaration

\array real_nums

 0.7   3.9  5.5 ! This line contains an array of 3 real numbers

\end 

This file has an array called 

\ARRAY DETECTOR_SYSTEMS

'JGGIANT'!idtype 1000-1999

'BEAM'!idtype 2000-2999

'TARGET'!idtype 3000-3999 

'TPC'!idtype 4000-4999

'CHAMBERS'!idtype 5000-5999

'CKOV'!idtype 6000-6999

'ROSY'!idtype 7000-7999

'TOF'!idtype 8000-8999

'RICH'!idtype 9000-9999

'CALORIMETER'!idtype 10000-10999

\END

GEANT geometry is defined using shapes made up of tracking media and placed in the mother volumes using translations and rotations defined in terms of rotation matrices. The rotation matrices and media are known to GEANT using integer numbers. In order to avoid conflicts in media and rotation matrix definitions, we define numerical ranges for these for each detector system as illustrated in the comment fields in the above \ARRAY definition.

Structure of detector RCP files

\ARRAY ROTATION_MATRICES      !Interrupt here to read more about this structure

\ARRAY MATERIAL_LIST          !Interrupt here to read more about this structure

\ARRAY MIXTURE_LIST           !Interrupt here to read more about this structure

\ARRAY MEDIA_LIST             !Interrupt here to read more about this structure

\ARRAY VOLUME_LIST            !Interrupt here to read more about this structure

\ARRAY DETECTOR_LIST          !Interrupt here to read more about this structure

\ARRAY CERENKOV_LIST          !Interrupt here to read more about this structure

RCPE files

Declaring RCP and RCPE files to the program

setenv BETA $cwd

ln -sf$BETA/hanuman.rcphanuman_rcp                                          

ln -sf$BETA/hanuman_generate.rcpehanuman_rcpe

The above declarations are done in setup.e907mc.rel. The important thing is to note is that an RCP file XXX.rcp is read in by the system as XXX_RCP. This is an old D0 convention

Fortran Coding standards

1. Every subroutine must have a header with the Author name, Date of Creation, Modification, Purpose of routine, Input and Output. 
2. All include files must be of the form #include ‘name.inc’
3. All code must be properly indented. The editor xemacs has an automatic way of doing this. Select the area you want to indent, and type in ‘esc’ followed by ‘ctrl-\’. It will make your code readable.
4. All code must be single operation per line. No Semi-colons.
5. Comments are encouraged strongly. Comments may be added at the end of a line by !comment.
6. All source code should be in upper case. Comments may be in lower case.
7. There should be no hard-coded constants in routines. All constants should be read in from RCP files. The programmer should familiarize him/herself with the routines EZPICK, EZGET and EZRSET.
8. The use of IMPLICIT NONE is mandatory in all routines. This forces declaration of all variables as logical,real etc.
9. The use of the construction 

logical first

data first/.true.

save first

----------------

if(first)then 

first = .false.

endif 

Is encouraged when wanting to initialize things in routines.

10. The use of common blocks is discouraged. If one must have common blocks, they should come in as include files as described above. The three main places the include files are found are shown in the example below. 

#include “geant321/gcdraw.inc” !from the directory $GEANT_DIR/src/geant321/geant321 

These paths are defined in the files Makefile and config.mk

11. All released code should reside in the CVS library.

An example of the code is as below. Only part of the routine is shown to illustrate the main points.

SUBROUTINE UGINIT

C----------------------------------------------------------------------

C-

C-Purpose and Methods : Initialisation

C-include standard GEANT3 init.;

C-Reading and initialisation of Run-time switches

C-Initialization and filling of ZEBSTP structure

C-for each detector

C-

C-

C-Inputs: None

C-Outputs : None

C-

C-Created27-APR-1998Rajendran Raja

C-

C----------------------------------------------------------------------

IMPLICIT NONE

C

#include "inc/gcunit.inc"

#include "inc/gcphys.inc"

#include "listvol.inc"

#include "end_kick.inc"

#include "maps.inc"

C

LOGICAL FIRST

DATA FIRST/.TRUE./

SAVE FIRST

C----------------------------------------------------------------------

IF(FIRST)THEN

CALL EZPICK('HANUMAN_RCP')

CALL EZGET('PRINT_MATERIALS',PRMAT,IER)

CALL EZGET('DO_INTERACTION_LENGTHS',DLAM,IER)

CALL EZRSET

ENDIF

Conly part of the routine shown.

CCALL SVSWCH! Save switches into RUNG bank; LQ(-1)

CCALL FLD0RG(9,72,ENTRY)! Fill version numbers

C

C

C****Print out various GEANT banks.

C

IF (PRMAT) THEN

CALL GPMATE(0)

CALL GPTMED(0)

CALL GPVOLU(0)

CALL GPROTM(0)

CALL GPSETS('*','*')

ENDIF

999RETURN

END

 Preparing Your Area

setenv CVSROOT e907cvs@cdcvs.fnal.gov:/cvs/e907 

setenv CVS_RSH /usr/krb5/bin/rsh #(path to kerberized rsh) 

Alternative means for accessing this cvs repository are described here.

The code resides in 3 libraries.

1.mipp/simulation/trim_d0lib containsthe RCP system and other routines in a trimmed down version of the RUN I D0library.

2.mipp/simulation/dd_geant contains the data-driven code that is experiment independent.

3.mipp/simulation/e907mccontains the E907 specific RCP files and magnetic field routines etc.

In order to fetch the modules from CVS, perform in your work area

cvs co mipp/simulation/trim_d0lib

cvs co mipp/simulation/dd_geant

cvs co mipp/simulation/e907mc

These commands should fetch the modules belonging to the 3 libraries.

Building the Needed Libraries

cd trim_d0lib#gets to the root directory of trim_d0library

source setup.trim_d0lib# This sets up environment variables such as $d0library and $d0debug and $d0platform 

# edit setup.trim_d0lib--setenv d0debug DEBUG for debug version,setenv d0debug NODEBUG for nodebug version. 

gmake -f Makefile clean#will clean out all *.o and *.a files

gmake -f Makefile lib#will build all the sublibraries such as calor_util, srcp_util as well as a master library called trim_d0lib.a

To build dd_geant, perform

cd dd_geant#gets to the root directory of dd_geant

source setup.dd_geant#This sets up environment variables such as $d0library and $d0debug and $d0platform

#edit setup.dd_geant -- setenv d0debug DEBUG for debug version,setenv d0debug NODEBUG for nodebug version. 

gmake -f Makefile clean#will clean out all *.o and *.a files

gmake -f Makefile lib#will build dd_geant.a

To build e907mc, perform

cd e907mc#gets to the root directory of e907mc

source setup.e907mc#This sets up environment variables such as $d0library and $d0debug and $d0platform

#edit setup.e907mc -- setenv d0debug DEBUG for debug version,setenv d0debug NODEBUG for nodebug version. 

gmake -f Makefile clean#will clean out all *.o and *.a files

gmake -f Makefile lib#will build e907mc.a

Building and running the E907mc executable

gmake -f Makefile bin#will build the executable e907mc.x

Before one builds the executable, it is necessary to have executed the command “Source setup.e907mc to setup the environment variables such as $d0library. Before executing e907mc.x , it is necessary to setup the links to the RCP files etc. This is done by

source setup.e907.rel#This has to be done only once.

Further,

source setup.interactive.rel#will run program in an interactive mode

source setup.generate.rel#will run program in a batch mode to generate events and record them on fort.2

source setup.analyze.rel#will run program in a playback mode to analyze generate events.

Library Linking Order and the lddum routines

There exist a number of routines that are present in dummy or duplicate form in all three or any two of the libraries.

In order to link things correctly the following technique is used with lddum routines.

The main routine hanuman.Fin /e907mc is structured as follows.

     PROGRAM HANUMAN

C----------------------------------------------------------------------

C-

C-   Purpose and Methods : MAIN program for 

C-          "HADRON NUCLEUS MEASUREMENTS ARE NECESSARY EXPERIMENT"

C-

C-   Created  27-APR-1998   Rajendran Raja   

C-

C----------------------------------------------------------------------

      IMPLICIT NONE

      LOGICAL LNKINC

      DATA LNKINC/.TRUE./

C----------------------------------------------------------------------

C

      CALL HNMAIN   

C

C  The following call to lddum is a dummy call just to get geant routines

C  loaded that are only called from geant and reside in geant.olb.  

C  the call must never actually be executed.......

C

      IF(.NOT.LNKINC) CALL LDDUM_E907MC

C

C LDDUM_XXX is a subroutine that calls all the E907mc specific routines that are

C different version of routines in either dd_geant, trim_d0lib/d0geant or GEANT321.

C this technique ensures that the proper routines get loaded. 

C

      STOP

      END

ANALYZING and Playing Back Events