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Subject: Re: Fall 2008 MATLAB Contest, November 5th-12th
Date: Mon, 10 Nov 2008 17:20:18 +0000 (UTC)
Organization: Ohio Supercomputer Ctr
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I've discovered an interesting bug in the code I can't quite track down.  

One of the things the contest machinery does that the runcontest code doesn't is seed the random number generator at the start of each run (which is why identical code submissions get identical results).  In order to make it easier to track the affect tweaking changes have on the code, I added the following line at the start of runcontest.m:  rand('twister',0)  As a result, I get consistent run-to-run results.

However, the current King of the Hill (Nearly immortal 8, #50873) and leading entry (MutantCat 6, #51068) crash the test suite whenever I run them  I can run each of the test boards individually just fine, however when I run the entire contest, it crashes with the following error:

??? Attempted to access r(0); index must be a positive integer or logical.

Error in ==> solver at 143
            dRow = sign(r(pick)-2); % convert to contest directions

If I remove the rand seed, the test suite doesn't crash.  

Looking at the failed entries listed at http://www.mathworks.com/contest/armyants/rankings.html , this has now happened DOZENS of times on the actual contest machinery.  Particularly with a lot of the entries just submitted in the past hour.  

I'm not sure what the solution is to this, however it is an interesting side affect of the current code being so stochastic.