What is Gaussian?
Gaussian is a series of electronic structure programs. Designed to model a broad range of molecular systems under a variety of conditions, it performs its computations starting from the basic laws of quantum mechanics.
Which version of Gaussian is available?
Gaussian 03 (G03) is currently installed in the hpcpower system.
G03 can be run in serial mode, SMP mode (execution using both processors of a node) and also the tcp/linda parallel mode.
How to use Gaussian 03?
In order to use G03, users must be assigned in the group of "student" (contact Mr. Kwan Wing Keung or Mr. Frankie Cheung). Users also have to add the following 2 lines in the .bashrc file:
. /share/bin/g03.sh
. /share/g03c02/gv/init_gv.bash
Users have to submit batch jobs using the PBS job queue system. Please study the instructions on using PBS in the User Guide of hpcpower.
The file /etc/skel/g03.cmd is the most updated job command file. Explanation is embedded in this command file. You can copy it to your home directory and submit it using the command qsub g03.cmd.
Execution of Gaussian 03 using 2 CPUs in the same node
G03 can also be run using 2 CPUs in the same node for speed up. In order to do this , you should add " %NprocShared=2 " to the Gaussian input file and you must specify the request of both CPUs of the node using this script in the job command file:
#PBS -l nodes=1:ppn=2
It means "Please give me one node, and I need 2 Processors Per Node".
Both CPUs in the node will participate in the calculation, with the data communication carried out through the shared memory.
The file /etc/skel/g03.cmd is the most updated job command file. Explanation is embedded in this command file. You can copy it to your home directory and submit it using the command qsub g03.cmd.
Execution of Gaussian 03 using more than 1 node
G03 can also be executed using more than one node by running on top of the tcp/linda software platform. You have to specify the request of several nodes in the job command file, for example:
#PBS -l nodes=4:ppn=2
It should be noted that not all links in g03 can be efficiently executed in a parallel computing environment due to the high communication overhead. User should test his specific problem before requesting for too many nodes for execution.
The file /etc/skel/g03l.cmd is the most updated job command file. Explanation is embedded in this command file. You can copy it to your home directory and submit it using the command "qsub g03l.cmd".
For any questions about Gaussian , please contact Mr Kwan Wing Keung kwk@cc.hku.hk or Mr. Frankie Cheung frankie@cc.hku.hk .
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