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Subject: Re: Pro Deo [clear hash table always/never]

Author: Uri Blass

Date: 02:44:37 11/16/04

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On November 16, 2004 at 04:47:52, Joachim Rang wrote:

>On November 16, 2004 at 04:38:57, Günther Simon wrote:
>
>>On November 16, 2004 at 03:16:35, Joachim Rang wrote:
>>
>>>On November 16, 2004 at 01:46:47, Kurt Utzinger wrote:
>>>
>>>>On November 15, 2004 at 15:42:01, Albert Silver wrote:
>>>>
>>>>>On November 15, 2004 at 13:37:01, Kurt Utzinger wrote:
>>>>>
>>>>>>Nunn2 match (60m+10s) 40 games
>>>>>>Pro Deo 1.0 vs Fritz 8.0.0.26
>>>>>>http://www.utzingerk.com/pro_deo.htm
>>>>>>
>>>>>>A little test should show the influence of the option [clear hash table =
>>>>>>always] and [clear hash table = never]. Below the result against Fritz 8 as Pro
>>>>>>Deo had the worst result against this engine:
>>>>>>
>>>>>>Option [Clear Hash Table = Always]
>>>>>>PD = 32.5 %
>>>>>>13.0 - 27.0
>>>>>>
>>>>>>[Clear Hash Table = Never]
>>>>>>PD = 36,2 %
>>>>>>14.5 - 25.5
>>>>>
>>>>>I ran some Nunn2 blitz matches as you know, with and without, and the results
>>>>>were not clear. Against Aristarch and Ruffian the results were better, and
>>>>>against List, PD scored 1 point less.
>>>>>
>>>>>                                          Albert
>>>>
>>>>
>>>>      Hi Albert
>>>>      Is it worth to replay all remaining 280 games
>>>>      at time control 60m+10s with clear hash table
>>>>      = never http://www.utzingerk.com/pro_deo.htm
>>>>      Kurt
>>>
>>>
>>>why should clear Hash Table = Never be an improvement? ProDeo looses important
>>>information when it clears the hashtable? Why is this option tested? Did Ed
>>>mention that he is not clear whether it helps or not?
>>>
>>>regards Joachim
>>
>>Hi Joachim,
>>
>>You sure meant 'clear hash table = always' in your statement above?
>>The reason for not using that option is that ProDeo seems to have some
>>kind of hashtable bug and sometimes plays weird blunder moves from
>>the hashtable. (users reported such blunders here)
>>I have experienced such blunders too in RWBC so far, nevertheless I still
>>use 'never', as Ed suggested this in relief that the overall success
>>should be better, even with some occasional big blunders.
>>
>>Best regards,
>>Günther
>
>
>Yes Günther you are right. I confused Never/Always. The only think I can imagine
>clearing the hashtables should help is if there is a bug, like you Uri and other
>mentioned. I didn't know that there are suspicions of such a bug in Rebel.
>
>regards Joachim

You should always suspect about bugs.

I suspect that the top programs can be more than 100 elo better if the
programmers only fix the bugs and change the personality.
Part of the problem is that the programmers do not know where are the bugs and
sometimes bugs can be even be productive for playing strength unless you change
the personality(for example if a program does not prune enough some bug of
pruning more lines based on conditions that are irrelevant for pruning may be
productive because the bug may mean that the program at least prune enough in
part of the cases when the bug increase pruning).

I know it because it is exactly what happened with movei when the program played
worse because of fixing some bug and it took me time to understand the reason.

After changing parameters the program seemed to play better again but
I did not dare to change the pruning paramaters enough so
I gave beta testers to test possibility of more pruning and compare with the
latest version that I tested and result so far are very good

see http://www.husvankempen.de/nunn/ratingaegt1511.txt

14 Movei 00_8_291a                : 2640   52  42   161    54.0 %   2612   31.1
30 Movei 00_8_291                 : 2578   68  55   100    52.5 %   2561

Note that the only difference between movei00_8_291a and movei00_8_291 is that
00_8_291a has more pruning based on evaluation and other factors when the
remaining depth is small.

Uri



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