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Linux Hall C Analyzer installation kit

The Hall C analyzer can be run on most reasonably current x86 Linux systems. While not exaustive, some of the requirements include:

Redhat Linux 6.1 (x86) with egcs and egcs-g77 installed. Older versions of Redhat, or other versions of Linux may also work if egcs and egcs-g77 are installed. The two scripts used to setup the analyzer do use the rpm command, so will not work properly with different versions of Linux.
Lots of memory. 32 MB or more is recommended, 16 will probably work.
Lots of disk space.
Familiarity with building and using the Hall C analyzer on the JLAB Sun machines. For information on doing this see: running the Hall C analyzer.

Getting started

Download the file grover_rh2.tgz. Pick a directory to to untar it into. Lets call this directory GROVER. (In my case, GROVER was ~saw/grover). It is untarred with

        mkdir GROVER
	cd GROVER
	tar -zxf grover_rh2.tgz

System configuration

Before compiling anything, you need to make sure that the Linux fortran compiler, G77 is installed and that several useful directories are NFS mounted to your system.

The easiest way to do this is to run the script grovermount. This will install g77 if it is not installed. It will also setup the automount daemon so that the following NFS directories are avaiable:

     /mnt/Csoft           Analyzer source tree (from wood.jlab.org)
     /cache               SILO cache disk
     /apps                Computer center Linux applications disk
     /site                Computer center site specific applications
     /u/mirror            Mirror of Redhat and other linux ftp sites

To run this script, logon as root and then execute the script grovermount:

	cd whatever/GROVER
	./grovermount

This script uses the autofs package to make remote directories available with the automounter. If you are already running the automounter, then it will ask if you want to override the configuration. If you are not sure, say no, study the grovermount script, and impliment changes by hand.

The grovermount script will also offer to install xntpd, the Network Time Protocol Daemon. This will keep your Linux machine synchronized with the correct time and is a good idea.

Setting up the analyzer source tree

The following instructions set up the master source tree (Csoft directory) against which individual users may build personal analyzers.

Edit the file GROVER/Groverup. Find the line that starts with "Csoft_READONLY". Set the definition of the variable to the path of the directory Csoft that has been NFS mounted above. If necessary, edit the definition of CERN_ROOT on the next line. If you have used the grovermount script as is, then these modifcations will not be necessary.
Pick an account from which to administer the analyzer software for the Linux machine. From the root directory of that account source the Csoftup script:
```
	cd ~
	source GROVER/Groverup
```
Groverup will ask how you want to setup the source tree directory. If you choose the "local" option, it will copy the analyzer source tree from /group/hallc/saw/Analyzer. If you choose the "nfs" option, the source code will be accessed through NFS, but will still be compiled locally. Grover will add environment variables to ~/.bash_profile and also define these variables for the current logon. These variables are
```
	NFSDIRECTORY	The location of the NFS mounted readonly copy
			of the analyzer source code.  This is only set 
                        if the "nfs" option  is chosen above
	CERN_ROOT	Directory containing CERN bin and lib directories.
	Csoft		The local copy of the master source and library tree
```
Groverup also creates the Csoft directory tree with all of the appropriate makefiles and source code.
Do the commands
```
	cd $Csoft
	make
```

Setting up a "replay" directory in a user account

Each user that will do analysis on the Linux machine must set up a replay directory similar to what is set up on HP workstations. The following procedure may be used.

Create a replay directory under your HPUX account using the Oscar procedure.
Make a tar file of the replay directory made by oscar. For example, if the replay directory is ~/replay, type
```
	tar -zcf myreplay.tgz ~/replay
```
Transfer this tar file to your Linux account.
From your home directory untar the tar file with, for example,
```
	tar -zxf myreplay.tgz
```
Edit or create ~/.bash_profile. Copy from the .bash_profile made by Groverup the definitions for CERN_ROOT and Csoft. Also add to this file the proper definition for ENGINE_CONFIG_FILE. Most likely this will be
```
	export ENGINE_CONFIG_FILE=~/replay/REPLAY.PARM
```
Go to the SRC directory under replay.
Using the file Makefile in the GROVER directory, modify the Makefile in the SRC to be Linux compatible. Your Makefile may already have these modifications.
Type make. This should compile a personal analyzer.
If you get errors in compiling, you may need to update some of the fortran files in SRC to be compatible with g77. See the section G77 Compatibility Issues below.
Copy some data runs to local disk, edit REPLAY.PARM appropriately and replay.

Getting data files

The cache disks, which hold data runs that have been retrieved from the silo can be read-only mounted by any machine at TJNAF. The grovermount script above should have mounted these cache disks directory under /cache. The command to request that files be placed in the cache directory must be run from a CUE machine.

If a data run is to be analyzed several times, it is helpful to copy it to a local drive.

Other ways of getting data files

Any command that sends a data file to standard output may be used in the Hall C analyzer to get a run. For example, rsh might be used if the data file is not in the silo and thus can't be moved to the cache disks. For example, the following filename specification will work for recently acuired data on cdaqh1.

g_data_source_filename = 'rsh cdaqs1 -l yourusername "cat /home/cdaq/coda/runlist/dec97_%d.log"'

For the remote shell command to work, you must list the node name of your linux machine in the .rhosts file in your home directory on cdaqh1. This is generally considered not to be a good idea from a security point of view.

Using compressed files

Saving compressed files on your local disk can increase the amound of data that you can hold locally. File name secifications like

	g_data_source_filename = '|gunzip < nov96_%d.log.gz'

will decompress the data file on the fly. The event reading routines will actually automatically detect compressed files and decompress them, so the specification

	g_data_source_filename = 'nov96_%d.log.gz'

is sufficient.

Note to users of non Hall C applications:. If you are trying to apply these techniques of retrieving data to CODA replay applications other than the Hall C analyzer, you may need to get the improved version of evio.c.

G77 Compatibility Issues

Some of the fortran code used in the Hall C analyzer is not compatible with G77. It is possible to modify the code to be compatible with G77 and remain comptible with the fortran compiler on SunOS. The main Hall C analyzer source tree is being upgraded with these changes. (So far, only /group/hallc/saw/Analyzer has had these modification applied.) So there should be no problems compiling the source tree in ~/Csoft/Analyzer. However, the source code from the replay or "Oscarup" directory may not have all these modifications.

Format statements

The blank format code x is sometimes used without a numerical argument such as:

111    format(i3,x,f10.5,x,f9.5,x,f10.5,x,f9.5,x,f7.3)

In such cases the x should be replaced with 1x:

111    format(i3,1x,f10.5,1x,f9.5,1x,f10.5,1x,f9.5,1x,f7.3)

Logical comparisons

G77 has a problem with logical comparisons such as:

       if(jiand(CRAW(2),'FFFF'x).eq.'10CC'x) then

This is because left side of the .eq. is an integer type and the right side is untyped. Lines like this can fixed by taking the exclusive or (jieor) of the two sides of the .eq. and comparing the result with zero. For example, the above line can be replaced with:

       if(jieor(jiand(CRAW(2),'FFFF'x),'10CC'x).eq.0) then

Character string arguments

If a subroutine has a character string as an argument, the variable must be declared as a variable width string. If this is not done, seeming unrelated and difficult to debug errors will result. So far this has been found to be a problem in some versions of the routine g_analyze_misc.f where the declaration:

       character*1024 errmsg

must be replaced with:

       character*(*) errmsg

Initializing variables

According to the Fortran definition, variables must be initialized before use. Most compilers though set defaults values of zero or .false. for variables and some of the Analyzer code depends on that. However, the g77 compiler does not initialize variables. In particular, this can cause problems with engine.f as many copies of it don't initialize the logical variables used to control the event loops. Make sure that the following lines are near the top of engine.f

      ABORT = .false.
      problems = .false.
      EoF = .false.
      finished_extracting = .false.

Last modified: Wed Feb 2 10:45:35 EST 2000

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