Author: Bas Hamstra
Date: 01:51:38 07/05/01
Go up one level in this thread
On July 05, 2001 at 03:30:06, Uri Blass wrote: >On July 04, 2001 at 20:20:41, Bas Hamstra wrote: > >>On July 04, 2001 at 01:00:38, Uri Blass wrote: >> >>>On July 03, 2001 at 18:17:36, Bas Hamstra wrote: >>> >>>>On July 03, 2001 at 17:18:25, Uri Blass wrote: >>>> >>>>>On July 03, 2001 at 16:59:02, Bas Hamstra wrote: >>>>><snipped> >>>>>>Personally I have a problem believing it is possible to maintain such a rating >>>>>>while searching 4 ply. >>>>> >>>>>I have no problem to believe that it is possible to maintain such a rating while >>>>>searching 4 plies. >>>>> >>>>>You only need to call the rest of the plies in the name: "extensions". >>>>> >>>>>Uri >>>> >>>>That is hardly possible. At first I would say it is impossible to search only 4 >>>>4 "quiet" positional moves and still survive. What about a subtil tactic made >>>>out of many quitet moves? But then again, Genius does quite an impressive job >>>>with only 6 ply positional and a huge tactical search on top of that. Ok, >>>>possible in principal, but very difficult. >>> >>>I guess that you do not have chessmaster6000 >>>It shows very small depthes in the first number >>>chessmaster6000(ss=10) is even worse and often needs some minutes to get into >>>depth 2. >>> >>>Chessmaster6000 shows 2 numbers. >>>I guess that the first number is the brute force and the second number is search >>>with null move pruning. >>> >>>depth 1/11 means 1 ply brute force and 11 plies with null move >>>pruning+extensions so the main line is usually more than 11 plies. >>> >>>If you call search with null move pruning extensions you have no problem to see >>>that chessmaster(ss=10) is searching usually less than 4 plies in the middle >>>game. >>> >>>It is only a question of definitions >>> >>>Uri >> >>If you call search with nullmove pruning extensions? Except this is nonsense > >Why nonsense? Is there a rule to say what extensions can include? There is consensus about what an extension is. When, in the full width part of the search, you search a move deeper than normal on certain grounds, it is called an extension. You are extending the normal search depth for that move. Therefore to say "I call everything above 4 ply extensions" is nonsense, if we want to stick to the normal meaning of the word "extension". If we invent our own definitions all the time, it becomes a little difficult to have a meaningfuill conversation. >Suppose someone is using another selective algorithm without null move. >Is there a rule when to call it extensions and when to call it depth? Yes. 99.99% of all chess programs work by searching to a fixed depth and doing a qsearch after that. If you extend that fixed depth search it is called an extension :-) >, I >>think you misinterprete those 1/11 numbers. >> >>Bas. > >What is the meaning of them? > >My guess is that it means: >1)1 ply of brute force and no null move pruning. >2)11 plies of search with null move pruning >3)A lot of extensions so practically chessmaster has no problem to see thins >like mate in 18 at depth 1/11. I am not sure, but my guess is this. In principal up till 11 ply it sees everything that a normal 11 ply nullmove search would see. Plus, for the first 6 plies it looks for forced lines and follows them very deep (SE=6). To do this heavy extending all the time would cost too much search depth, therefore he restricts it to the plies near the root, where it's most dangerous. Bas.
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