Author: martin fierz
Date: 08:21:37 02/24/04
Go up one level in this thread
On February 24, 2004 at 11:14:00, Robert Hyatt wrote: >On February 24, 2004 at 09:27:26, martin fierz wrote: > >>On February 23, 2004 at 11:14:28, Robert Hyatt wrote: >> >>>On February 23, 2004 at 07:02:59, martin fierz wrote: >>> >>>>aloha, >>>> >>>>i have a question about pins. pins are a rather important feature in chess; some >>>>of them are not so bad, some are deadly. i just happened to chat briefly with >>>>anthony cozzie on ICC, and he said he didn't do any pin detection. i detect >>>>pins, but i don't evaluate whether a pin is not so bad or deadly. my questions >>>>are: >>>>-> are you detecting pins in your program? >>>>-> if yes, do you try to distinguish between different pins? >>> >>>No and No. I don't do it as I have not found it very important. IE with the >>>depth I hit today, if a pin is important, the search can go deeply enough to >>>discover this without much trouble. 20 years ago I was definitely evaluating >>>pins, as hitting 5-6-7 plies is not deep enough to see the consequences of a >>>pin, whereas todays 12-16 plies in longer games is more than enough in most >>>cases. >> >>interesting - and a possible explanation why i believe i need them. muse >>searches something like 1-2 plies less than crafty on equal hardware (meaning >>single-processor hardware of course...), and i play blitz matches. so i'm >>getting something in between of your 5-7 and 12-16 plies; meaning that i am >>closer to needing pin detection than you are :-) >> >>cheers >> martin > >You are also in the danger-zone for null-move R=2 and R=3 as well, at those >depths. If you look at the comments in main.c in Crafty, you will see how many >times I tried R=2 from 1994 to date, and how many times it failed, until the >depth reached a point where null-move didn't hide too many tactics... > >Depth is definitely part of the formula, and the deeper we go, the more things >change in unexpected ways... i'm using adaptive R=2 / R=3; R=3 at depths > 6. i once tried using R=3 all the time with bad results. i know i still have to work on my search a bit :-( cheers martin > >> >>>There are exceptions, but the question has to be "is the cost of doing this >>>offset by the playing strength increase?" I believe that at least for my >>>program, the answer is "no". >>> >>>YMMV of course. >>> >>>> >>>>cheers >>>> martin
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