Author: Uri Blass
Date: 06:28:32 06/21/01
Go up one level in this thread
On June 21, 2001 at 05:56:46, martin fierz wrote: >On June 20, 2001 at 14:25:03, John Hatcher wrote: > >>Maybe the answer to my question is obvious, but I'd be interested in what >>programmers have to say on the subject. >> >>I've recently been running matches between Fritz6 and Chess Tiger. On my old >>Celeron 333mhz computer Fritz6 runs at about 250 knps, and Chess Tiger runs at >>about 80-100 knps. To my delight, and surprise, Chess Tiger is doing very well >>against Fritz - very well. >> >>Since, as I understand it, "nps" is related (at least nominally) to search depth >>in a given time period, it would seem that, all things being equal, the greater >>the "nps" the stronger the program. >> >>Of course, things are never really equal between two programs. As evidence of >>that, Chess Tiger with its lower nps holds its own quite nicely against Fritz. >>For this to happen it would seem that Chess Tiger must have some chess >>"knowledge" programmed into it that allows it go toe-to-toe with a program that >>searches 2.5x as many positions per second. >> >>Is the programming of this chess knowledge, even among the programmers of top >>commercial programs, still as much art as science so that the programmer of >>Chess Tiger has found a "smarter", more efficient way to implement chess >>knowledge into Chess Tiger. I guess I supposed that much of this knowledge >>would be common currency by now. >> >>Sorry for the long-winded question. I wanted to be clear. >> >>JOHN > >in my checkers program, i have various move ordering schemes. if i turn them on, >i get much less nodes/seconds, but i can search deeper all the same. the >same goes for ETC - using it lowers nodes/sec, but has a net positive effect. >i can choose to run my program at 1.1MN/sec without these things or at 750kN/sec >with them, and it's better in the 'slow' mode. >there may also be a big difference in the eval. i know fritz does something fast >but stupid: before starting the search, it assigns pieces values depending on >which square they are. these values remain unchanged during the search (AFAIK). >the result is a fast search but a dumb evaluation - i'm sure they tested it and >found it to be ok, but it can be very irritating at times. I am sure they testeed it and found it not o.k and this is the reason that Deep Fritz or Fritz6a almost do not do it. it is of course >well-known that if you have a king which is not too safe, you should try to >exchange queens. fritz eval understands this, and gives the attacking side a >bonus - BUT: in the lookahead, it keeps this in, even if the queens are traded. >it will evaluate a line with a queen trade as +1 for the side with the safe >king, but once the queen is gone, it will suddenly say 'equal' - which is >correct, but it didnt see it in the lookahead. i find this very disconcerting >when analyzing games with fritz... It seems that you have an old Fritz version. I do not see it with my Deep Fritz. Uri
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