# The ggamess script¶

GC3Apps provide a script drive execution of multiple gamess jobs each of them with a different input file. It uses the generic gc3libs.cmdline.SessionBasedScript framework.

The purpose of GAMESS is to execute several concurrent runs of GAMESS each with separate input file. These runs are performed in parallel using every available GC3Pie parameters.

## How to run GAMESS on the Grid¶

SSH to ocikbgtw, then run the command (it’s one single command line, even if it appears broken in several ones in the mail):

ggamess.py -A ~/beckya-dmulti.changes.tar.gz -R 2011R3-beckya-dmulti -s "a_session_name" "input_files_or_directories"


The parts in double quotes should be replaced with actual content:

a_session_name:

Used for grouping. This is a word of your choosing (e.g., “test1”, “control_group”), used as a label to tag a group of analyses. Multiple concurrent sessions can exist, and they won’t interfere one with the other. Again, note that a single session can run many different .inp files.

input_files_or_directories:

This part consists in the path name of .inp files or a directory containing .inp files. When a directory is specified, all the .inp files contained in it are submitted as GAMESS jobs.

After running, the program will print a short summary of the session (how many jobs running, how many queued, how many finished). Each finished job creates one directory (whose name is equal to the name of the input file, minus the trailing .inp), which contains the .out and .dat files.

For shorter typing, I have defined an alias ggms to expand to the above string ggamess.py -A ... 2011R3-beckya-dmulti, so you could shorten the command to just:

ggms -s "a_session_name" "input_files_or_directories"


For instance, to use ggames.py to analyse a single .inp file you must run:

ggms -s "single" dmulti/inp/neutral/dmulti_cc4l.inp


while to use ggamess.py to run several GAMESS jobs in parallel:

ggms -s "multiple" dmulti/inp/neutral


## Tweaking execution¶

Command-line options (those that start with a dash character ‘-‘) can be used to alter the behavior of the ggamess.py command:

-A filename.changes.tar.gz

This selects the file containing your customized version of GAMESS in a format suitable for running in a virtual machine on the Grid. This file should be created following the procedure detailed below.

-R version

Select a specific version of GAMESS. This should have been installed in the virtual machine within a directory named gamess-version; for example, your modified GAMESS is saved in directory gamess-2011R3-beckya-dmulti so the “version” string is 2011R3-beckya-dmulti.

If you omit the -Rversion” part, you get the default GAMESS which is presently 2011R1.

-s session

Group jobs in a named session; see above.

-w NUM

Request a running time of at NUM hours. If you omit this part, the default is 8 hours.

-m NUM

Request NUM Gigabytes of memory for running each job. GAMESS’ memory is measured in words, and each word is 8 bytes; add 1 GB to the total to be safe :-)

## Updating the GAMESS code¶

For this you will need to launch the AppPot virtual machine, which is done by running the following command at the command prompt on ocikbgtw:

apppot-start.sh


After a few seconds, you should find yourself at the same user@rootstrap prompt that you get on your VirtualBox instance, so you can use the same commands etc.

The only difference of note is that you can exchange files between the AppPot virtual machine and ocikbgtw via the job directory (whereas it’s /scratch in VirtualBox). So: files you copy into job in the AppPot VM will appear into your home directory on ocikbgtw, and conversely files from your home directory on ocikbgtw can be read/written as if they were into directory job in the AppPot VM.

Once you have compiled a new version of GAMESS that you wish to test, you need to run this command (at the user@rootstrap command prompt in the AppPot VM):

sudo apppot-snap changes ~/job/beckya-dmulti.changes.tar.gz


This will overwrite the file beckya-dmulti.changes.tar.gz with the new GAMESS version. If you don’t want to overwrite it and instead create another one, just change the filename above (but it has to end with the string .changes.tar.gz), and the use the new name for the -R option to ggamess.py

Exit the AppPot VM by typing exit at the command prompt.