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pMatlab Troubleshooting Checklist

On this page, you'll find a series of questions and answers that will help you resolve the more common problems with running pMatlab jobs on the SuperCloud system.

Job Launch Problems

In this section, you'll find a series of questions and answers that will help you resolve some of the more common pMatlab job launch problems.

Is your path set up to include the gridMatlab directories?

Launch MATLAB® and enter the path command in the MATLAB® command window. In the first few lines of the output, does the path include these directories from your SuperCloud home directory?

  • tools/gridMatlab/src
  • tools/pMatlab/src
  • tools/pMatlab/MatlabMPI/src
  • matlab

If not, check your startup code (startup.m, startup_local.m and any other startup code that is called from those files) for calls to clear all and remove those calls. Make sure your pMatlab script and code does not use clear all either.

Did you check whether there are resources available for running your job?

From the MATLAB® command window, enter the LLfree command and verify there are enough nodes and cores available for the CPU type that you requested. You can also enter LLfree at the Linux prompt if you are connected to the login node. Remember that if you are using triples mode to launch your job, you will be using whole nodes, so make sure there are enough nodes available.

Does the code that you're trying to run reside on the SuperCloud?

In order to run a job on the SuperCloud system, every processor must have access to all functions/methods in the code you are executing and any data the program accesses. Since every node can access your SuperCloud home directory or group shared directories, placing your code and data in your home directory or any group shared directory makes them accessible to the entire system.

If your code is not on SuperCloud, copy your code and any files that are needed in order to run your job to somewhere in your SuperCloud home directory. See Accessing and Transferring Data and Files for instructions on how to copy your files to SuperCloud.

If your code is on SuperCloud, confirm that your MATLAB® current working directory is somewhere in your SuperCloud home directory by running the pwd command.

- Did you try running the Param_Sweep example in your SuperCloud home directory?

The Param_Sweep example is located in $HOME/examples/Param_Sweep.

No: For instructions on how to run the Param_Sweep example, see the Verifying Your pMatlab Setup page.

Yes, it worked: the problem is probably in your code somewhere. Look in your job's log files for errors or other clues. See the page on Finding Your pMatlab Output.

You've tried and confirmed everything here and you still can't launch a pMatlab job

If you've tried and confirmed all of the above items and still can't launch a pMatlab job, please let us know what you've tried, and also copy, paste and send any errors that you see to supercloud@mit.edu. Please attach any files that might be helpful in diagnosing the problem.

References

Here is a list of webpages that were mentioned here, plus some others that might be helpful: