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

Author: Robert Hyatt

Date: 19:59:12 03/20/04

Go up one level in this thread


On March 19, 2004 at 08:25:31, James Swafford wrote:

>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?

800-1000 at least.  GMs will kill it with no eval.  With normal crafty they will
rarely win a blitz game...


>
>
>--
>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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