Computer Chess Club Archives


Search

Terms

Messages

Subject: Your engine was bewitched ;). (n/t)

Author: Matthias Gemuh

Date: 00:24:00 04/03/04

Go up one level in this thread


On April 02, 2004 at 21:39:14, Dan Honeycutt wrote:

>This post is for other beginners like myself.  You veterans are welcome to read
>and laugh but no comments are necessary.
>
>I recently checked to see how my engine was doing in a test match and found it
>in a dead-drawn, blocked-pawn, opposite-color bishop ending.  The other engine
>showed a draw score but poor Bruja, clueless, thought it had a slight advantage
>and wanted to fight on.  I thought about adjudicating but browsing the score
>showed nothing had happened for some time so I figured the game had to soon end
>by 3 rep or 50 move rule.
>
>Then I noticed the output.  Bruja was reeling off plys like pennies at the gas
>pump with today's high prices.  My first thought was "wow, hash tables really
>help in these positions with so few pieces".  I became uneasy when the depth
>passed 20 and downright worried when it passed 40.  Terror gripped my heart when
>the depth flew past my array dimensions.  I watched helpless, waiting for the
>crash and wondering what was wrong with my bounds checks.
>
>After iteration 379 Bruja decided it had searched deep enough and played.  The
>other engine replied and the game ended in a 50 move draw.  The postmortem was,
>fortunately, fairly simple.  I had bounds checks in the search but nothing in
>the iteration function.  Iterate called search which promptly returned as all
>moves led to a draw two plys.  Iterate incremented the depth, recalled search
>with the same result until the time allocation finally ran out.  (I should have
>noticed that the whole time the pv was only 2 moves but i was fixated on the
>depth.)
>
>Others with green engines may want to check to see that they don't have a
>similar situation.
>
>Dan H.



This page took 0 seconds to execute

Last modified: Thu, 15 Apr 21 08:11:13 -0700

Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.