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	<title>Comments on: Jan Langer Wins Darkness</title>
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	<link>http://blogs.mathworks.com/contest/2008/11/06/jan-langer-wins-darkness/</link>
	<description>The MATLAB Programming Contest is a semi-annual competition where contestants submit MATLAB code to try to solve a challenge.  For more information, see http://www.mathworks.com/contest/overview.html</description>
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		<title>By: Alan Chalker</title>
		<link>http://blogs.mathworks.com/contest/2008/11/06/jan-langer-wins-darkness/#comment-6499</link>
		<dc:creator>Alan Chalker</dc:creator>
		<pubDate>Fri, 07 Nov 2008 18:26:33 +0000</pubDate>
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		<description>While we&#039;re all waiting for the queue to clear and get into daylight, I thought it&#039;d be a good time to post my traditional analysis of the scoring formula.  As in past contests, the formula is:

score = k1*result + k2*e(k3*runtime) + k4*max(cyc-10,0) + k5*nodes

The coefficients were only slightly tweaked compared to the spring contest, as the contest team typically does:

k1 = 1
k2 = 0.1
k3 = 2/30 (0.06666666…)
k4 = 1
k5 = 0.001 

The current leading entry has a time of 161s, result of 22940, cyc of 54, and nodes of 1583. Here’s a breakdown of the current tradeoffs:

-cyc and score are a 1:1 ratio (i.e. each point shaved off cyc is a point shaved off the score)
-time and score are a 1:295 ratio
-result and score are a 1:1 ratio
-node and score are a 1:0.001 ratio

Note that the time component is at a very steep slope in the exponential curve.  Adding just 5 seconds changes the ratio to 1:412, whereas saving 5 seconds changes the ratio to 1:226.  It&#039;s not until we drop the time to about 75s that the ratio gets down to 1:1.

So what does this all mean?  

1. Well given that we already know the shortest amount of time is never going to drop below about 70s due to the &#039;overhead&#039; caused by the contest machinery, it will always be better to work on faster code than to work on a better result, unless there is some major algorithmic breakthrough.  

2. Since it appears that all the codes have quite a bit of randomness in them as part of the &#039;searching phases&#039;, submitting the same code multiple times will likely yield very different scores.  We already know from past contests that the contest system can have quite a variable workload, which results in small, but significant time differences.  Just a small amount of change in the time can majorly alter the score one way or the other.</description>
		<content:encoded><![CDATA[<p>While we&#8217;re all waiting for the queue to clear and get into daylight, I thought it&#8217;d be a good time to post my traditional analysis of the scoring formula.  As in past contests, the formula is:</p>
<p>score = k1*result + k2*e(k3*runtime) + k4*max(cyc-10,0) + k5*nodes</p>
<p>The coefficients were only slightly tweaked compared to the spring contest, as the contest team typically does:</p>
<p>k1 = 1<br />
k2 = 0.1<br />
k3 = 2/30 (0.06666666…)<br />
k4 = 1<br />
k5 = 0.001 </p>
<p>The current leading entry has a time of 161s, result of 22940, cyc of 54, and nodes of 1583. Here’s a breakdown of the current tradeoffs:</p>
<p>-cyc and score are a 1:1 ratio (i.e. each point shaved off cyc is a point shaved off the score)<br />
-time and score are a 1:295 ratio<br />
-result and score are a 1:1 ratio<br />
-node and score are a 1:0.001 ratio</p>
<p>Note that the time component is at a very steep slope in the exponential curve.  Adding just 5 seconds changes the ratio to 1:412, whereas saving 5 seconds changes the ratio to 1:226.  It&#8217;s not until we drop the time to about 75s that the ratio gets down to 1:1.</p>
<p>So what does this all mean?  </p>
<p>1. Well given that we already know the shortest amount of time is never going to drop below about 70s due to the &#8216;overhead&#8217; caused by the contest machinery, it will always be better to work on faster code than to work on a better result, unless there is some major algorithmic breakthrough.  </p>
<p>2. Since it appears that all the codes have quite a bit of randomness in them as part of the &#8216;searching phases&#8217;, submitting the same code multiple times will likely yield very different scores.  We already know from past contests that the contest system can have quite a variable workload, which results in small, but significant time differences.  Just a small amount of change in the time can majorly alter the score one way or the other.</p>
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