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Maxwell User Guide

Maxwell is a hybrid cluster with Intel Xeon and AMD Opteron processors. The cluster currently runs Rocks and Red Hat Enterprise Linux. The login node can be reached via ssh at

Please submit a ticket if you need help.

Maxwell has multiple editors installed including vi, emacs and nano.

Modules are a tool for users to manage the Unix environment in Maxwell. It is designed to simplify login scripts. A single user command,
$ module add
can be invoked to source the appropriate environment information within the user’s current shell. Invoking the command,
$ module avail
will list the available packages on the system. Also,
$ module rm
will remove the environment information from the user’s current shell. The module command can be placed in a shell startup file to have the environment set upon login.

GCC – GNU Compiler Collection. This is the default compiler suite available to all users when they login. The compilers include gcc, g++, and gfortran. The current version 4.1.2 for gcc, g++ and gfortran are installed. Intel, PGI compilers are available through the module command.

OpenMPI – The OpenMPI tools and compilers are available for developing and running MPI jobs. 

Maxwell uses the Maui scheduler and Torque resource manager to manage the execution of job on the cluster. The command for submitting jobs on the cluster is “qsub”.
The batch queue runs jobs using the fastest compute nodes available at that time.
The batch queue will route your job to the appropriate queue based on the walltime specified when you submit your job.

Some example job submissions:
To open an interactive session on a compute node
$ qsub -I

Same as above, with X forwarding
$ qsub -I -X

To submit a batch script
$ qsub

Example Job

#!/bin/sh  #PBS -N example_job 
# The name of the job #PBS -l mem=2gb 
# Memory Allocation for the Job #PBS -M 
# Email address to send job status notification #PBS -be my_job.err 
# Mail notification when the job starts and completes my_prog

Sample MATLAB job submission script

#PBS -l walltime=10:00:00
#PBS -l nodes=1:ppn=1
#PBS -l mem=2gb
#PBS -N matlab_job 
#PBS -j oe
module load matlab 
matlab < your_file.m > output.out

More examples of submission scripts can be found at Torque’s Quick Reference.

Other useful commands:
$ showq or qstat – look at the status of the queues/jobs
$ qdel 1234 – deletes job id 1234
$ checkjob 1234 – displays detailed job state information for job id 1234

The current status of the cluster, including load percentages and relevant statistics, can be viewed at the RCC Grid (Maxwell).