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Subject: Re: Ruffian's most peculiar way of pondering

Author: Uri Blass

Date: 02:14:07 03/28/04

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On March 27, 2004 at 22:38:40, Odd Gunnar Malin wrote:

>On March 27, 2004 at 21:13:53, Peter Berger wrote:
>
>>On March 27, 2004 at 21:07:11, Odd Gunnar Malin wrote:
>>
>>>On March 27, 2004 at 19:51:33, Peter Berger wrote:
>>>
>>>>For about a month I have waited for someone to bring this up now. Occasionally I
>>>>thought I should post about it, but then I thought someone else (a much more
>>>>knowledgeable guy at best) would do it anyway sooner or later. I decided to just
>>>>do it now and not bother to do it very well at all.
>>>>
>>>>This is about Ruffian 2.1.0 I bought at Lokasoft's ( it probably applies to
>>>>other Ruffian 2 versions too).
>>>>
>>>>Now how does Ruffian 2 ponder?
>>>>
>>>>Usually programs assume the second move of the PV as being played, and then
>>>>think as if it were their own move in the meantime. If the expected move gets
>>>>played indeed, some (loads of at times ) time has been saved - else the time is
>>>>lost (despite some potentially useful entries in the hashtable).
>>>>
>>>>Another approach ( inferior) is to just think as if you were the opponent during
>>>>ponder and rely on savings from the hashtable you achieved -you get some useful
>>>>entries in the hashtable anyway, but this can't be an optimal strategy IMHO.
>>>>
>>>>Now Ruffian _does_ think as if it were the opponent during pondering, too,  but
>>>>in case the expected move is played it does the same as the usual strategy does
>>>>during pondering but one ply further. The second move in the PV is the move to
>>>>be played in case time has already run out, else some time has been saved of
>>>>course. Again, if another move has been played, the time is lost.
>>>>
>>>
>>>If the engine is running as wb engine there is two methods to show the pv-line:
>>>
>>>1. Send a hint-move for your opponent move and then send the pv in normal way
>>>eg. starting with your next move.
>>>2. Put the hintmove in front of the pv for each time you send the pv.
>>>
>>>You are sure it isn't this second method you observe, eg. do it ever change the
>>>first move in the pv.
>>>
>>
>>Feeling more positive now as I at least thought about this obvious explanation
>>:).
>
>Still a bit strange since if it runs as uci there isn't an otion to show a pv
>like you describe so it will/should be quiet if it don't use the ponder move.
>And running as WB CP have problem showing a pv that start with the players move
>so I guess you look at the pv in the log-window.
>
>>Yes, it will change the first move; else I would obviously make no sense at
>>all.
>
>Well playing the second move from a pv-line doesn't make sense neither, maybe it
>does some advanced pondering with switching pondermove if current pondermove
>lower the score for the player too much eg. is a bad move.
>
>Odd Gunnar

I assume based on reports that I read Ruffian performs worse with pondering on
that it does something wrong so I will be surprised if it does something that
make sense instead of what peter describes.

Uri



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