Author: Vincent Diepeveen
Date: 17:37:36 11/24/98
Go up one level in this thread
On November 24, 1998 at 08:12:46, Robert Hyatt wrote: >>So there are 4 ways to test >> a) all extensions off, SE on >> b) all extensions on, SE on >> c) all extensions on, SE off >> d) all extensions off, SE off (which is the most uninteresting) >> >>The most interesting is to compare b with c. In fact S.E. should find this >>really quickly, but when i test this with S.E. on, then i'm suffering horrible >>from the reduction factor, which misses the advance of the c-pawn. >> >>In fact i find this move easier then without S.E. than with, as it eats >>up too many plies extending nonsense. >> >>here is the position (bs2830-26): >> >>1r4k1/1q2pN1p/3pPnp1/8/2pQ4/P5PP/5P2/3R2K1 b - - Qd5 > > >Did you implement the "real" singular extension algorithm as explained in the >JICCA along with the "sticky transposition table" stuff to avoid losing a >singularity at odd times? I did this in Cray Blitz and found it worked pretty >well in the right positions... As described yes, i used a translated version of it to Netherlands. If i remember well translated by Dennis Breuker in 'computerschaak'. Main problem is this reduction factor. you first reduce in depth in order to see whether it's singular in order to extend it. So you reduce it by 2 then extend it by 1. Of course: you reduce the OTHER moves by 2, and extend the RIGHT move by 1, but how can you DETECT that this right move is a singular move if you search the other moves by a reduced depth, where the only interesting singularism is derived from a search which is NOT reduced. Further a human doesn't use 'singularism'. Most combinations you have 2 or 3 interesting moves, and not only 1 forced moves. singularism is just a small subset of what humans do. Humans simply consider *all moves* that are interesting. this is very sometimes 1 move, more usually 2 or 3 or 4 moves. Sometimes a human simply 'nullmoves' or something like that. scanning for potential winners for the opponent, using *a lot* of chessknowledge to select a move. Not something with alfa or beta. Simply a line that *might* give counterplay without concerning about the return value of a small search. Anyway, i think Singular Extensions is something interesting for old programs with bad branching factors searching fullwidth. I think the future is for nullmove programs searching huge depths and a good move ordering and a limited form of pruning, meanwhile seeing a lot with quiescencesearch. Then programs like this play that well tactically and search that deeply, that they have no other option to improve it other than improving evaluation, as that is the weakest chain after you have an equal position after book, which is another thing that'll give a lot of trouble in the future. I'm seeing in the databases games of me when i was a huge rebel. Like 15 years old and only 1900+ rated. those games are used to make my book! Quite laughable! I blundered and missed all kind of positional shots in those days! Same for my opponents lucky, otherwise i'd never have won a game. Vincent
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