Sunday March 15, 2009
The Debugging problem walks you through a real bugger of a problem.
This problem uses debugging tools, e.g. TotalView, idb, or gdb, to test your knowledge of Un*x/MPI debugging.

As an attached resource, you will find a piece of C code titled 'bug_code.c' (check the resources for "BugCode"). The crux of this problem is to find out why this program isn't completing successfully when using multiple nodes.

A successful completion of this problem will require you to debug the issues in this process.

Your solution should include:
* A description of how you went about debugging this program.
* A description of how you attached to the program in order to assess the situation (if applicable)
* A description of how you resolved the issue that was preventing the program from normal termination
* A description of how to change the source code to obtain the desired outcome.

* You may need to use X-Forwarding (the '-X' command-line option to ssh) if you plan on using a debugger such as TotalView installed on a remote machine.
* Research ways to modify variables under the debugging tools that you have access to.

Please Note:

This and many of the following problem utilize the Message Passing Interface (MPI). Provided below are some helpful links for implementations and general information related to MPI; you may find these useful for future challenges.

- MPI Tutorials

-This blog gives some convenient tips on setting up Visual Studio and Mac OSX with MPI.

-MPICH2: MPI Implementation on Windows

-A variety of other MPI implementations.

-MPI Cheat Sheet
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