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Subject: Re: What is a good eval worth? (Some surprising results)

Author: James Swafford

Date: 05:25:31 03/19/04

Go up one level in this thread


On March 18, 2004 at 12:18:30, Robert Hyatt wrote:

>On March 17, 2004 at 21:19:45, James Swafford wrote:
>
>>Just what is a good eval worth?
>>
>>I ran Crafty on an AMD XP 2000+ (about 1.5 ghz) on ICC with a stripped
>>down eval, then with it's regular eval to find out.  Check out the
>>summaries below (the top one is for stripped eval, of course).
>>
>>By "stripped down", I mean that the eval counted only material, some
>>very crude pawn heuristics (doubled pawn, passed pawn, isolated
>>pawn), and used pawn and knight piece square tables.  That's it.
>>
>>I'm a bit surprised that the difference isn't a bit more; it's
>>less than 200 points for blitz and bullet.  I strongly suspect
>>the difference would've been much greater for standard games,
>>but I have no data to support that.
>>
>>Anyone done similar tests?
>>
>
>If you don;t restrict ratings, this isn't as revealing.
>
>IE against a 1800 player, tactics will rule the day, regardless of the
>evaluation.  So stripping ot parts of the eval won't make a lot of difference.
>But against a GM, it will do horribly with no eval...
>


You're clearly right, but I'm surprised by just how much.  I
was also surprised to see that the avg opponenet is so much
weaker than Crafty when ratings aren't restricted.

Maybe I'll do this again, with a rating window of +/- a few
hundred points.

What do you guess the difference would've been with that constraint?


--
James


>
>
>
>>
>> cnt |          avg          |          avg          | base_secs | inc_secs |
>>description
>>-----+-----------------------+-----------------------+-----------+----------+-------------
>> 271 | 2313.6531365313653137 | 1731.1623616236162362 |       120 |        1 | Br
>>   2 | 2431.0000000000000000 | 1031.0000000000000000 |       300 |        3 | bu
>> 673 | 2409.4680534918276374 | 1654.3239227340267459 |       300 |        3 | br
>>(3 rows)
>>
>> cnt |          avg          |          avg          | base_secs | inc_secs |
>>description
>>-----+-----------------------+-----------------------+-----------+----------+-------------
>> 246 | 2476.1422764227642276 | 1644.9471544715447154 |       120 |        1 | Br
>>   2 | 2436.0000000000000000 | 1845.0000000000000000 |       120 |        1 | Bu
>> 567 | 2583.1869488536155203 | 1653.4673721340388007 |       300 |        3 | br
>>
>>
>>--
>>James



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