IAM Matlab and Comsol Tips

This page explains the startup options and commands for the different versions of Matlab and Comsol (formerly Femlab) available in the IAM. With the exception of starting the nojvm (text) version of Matlab, it is recommended to execute these commands in the background by putting & at the end of the command line. After starting a computational task in Matlab/Comsol, its priority should be reduced, or its niceness increased, by using

renice new_niceness pid ,

where pid is the process id, and the new niceness level is set by default to 10 (see also manual pages for renice). pid is given by the shell upon issuing the Matlab startup command, and can also be retrieved by using the command

matlab_pid ,

which is an alias for

ps -eo pid,args | grep MATLAB | grep -v grep | awk '{print $1}' .

Similarly, the current niceness level of your Matlab job can be retrieved by using the command

matlab_ni .

If you want to renice your newly started Matlab process from 0 to 10, you can use the command

renice_matlab ,

which is an alias for

renice `ps -eo pid,args | grep MATLAB | grep -v grep | awk '{print $1}'` .

Alternatively to using renice from the shell, you can issue the top command, which will list the different processes running on the local machine, together with their id's and niceness levels. From top's internal command line, type r for renice, and then specify the pid corresponding to the Matlab/Comsol process.

Please note that the priority of any unreniced Matlab or Comsol jobs will be automatically changed to the lowest level, thus giving preference to those who have used nice or renice. Once the process is reniced, the user can only lower its priority; an attempt to increase the priority (reduce niceness) will produce a "Permission denied" message. Therefore, if you want to renice your Matlab job, do it immediately after starting it, before the system automatically renices it to an even lower priority.