Author: Anthony Cozzie
Date: 04:57:37 03/29/04
Go up one level in this thread
On March 29, 2004 at 06:05:20, Vasik Rajlich wrote: >On March 28, 2004 at 22:44:27, Artem Pyatakov wrote: > >> >>>I think you and Steven both enjoy thumbing your noses at the "conventional, >>>hat-trick, alpha-beta seachers". I am not quite sure why, but whatever floats >>>your boat . . . >>> >>>anthony >> >>Well, I've explained my objections to it. Don't get me wrong, I am one of those >>people - I have written a program that uses all of the tricks I criticize. But >>my objection to it is that a lot of these tricks are not beneficial for research >>in related fields - even close ones like playing other games, and thus it would >>be nice to change philosophies. It would also be much more elegant to be able to >>have computers learn the tricks themselves, don't you think? >> >>Artem > >Hi Artem, > >it's great that you have lots of ideas. Lots of people here have lots of ideas. >The questions eventually are, what do you hope to accomplish, and how can you >fit your ideas into a framework to help you accomplish it. > >This is a constant process for example at the level of evaluation. I constantly >find positions I'd like my engine to evaluate differently. Usually, it's not >hard to find some way to try to capture it. However, I expect my evaluation to >have a certain level of speed and simplicity, and changing this would mean >changing the whole framework. (Ie slower evaluation means you should do things >differently in search, etc.) I won't, for example, look for exact patterns >inside my evaluation - that's outside its bounds. So, often, the conclusion is >that the idea has no sensible implementation. > >Re. alpha-beta, I have lots of ideas for how to expand it into something more >human-like. For example, yesterday I played a chess game for my club in which I >sacrificed a piece for an attack, and in a number of positions the move Ke1-d2 >deserved serious consideration, to avoid later checks on the e-file. >Furthermore, Ke1-d2 was better than castling queenside (which was still >allowed), because the king should support a later Re1. After the game, I started >thinking: how can you avoid reducing a move like Ke1-d2? This is exactly the >sort of move which makes selective searching so hard. In most positions, of >course, it's about the last move to consider when you are trying to justify a >sacrificial attack - especially when the safer queenside castling is possible. > >A human considers this move because later in the tree, checks along the e-file >play a role. How would this look inside the alpha-beta framework? Maybe >something like: if one side fails high in some "pv-like" (ok already MTD (f) has >some issues ...) variation by giving a check, then "pay special attention to" >all king moves earlier in the search. Unfortunately, this simply doesn't fit >inside alpha-beta. In MTD (f) you may research based on the score, but I don't >know of any alpha-beta framework inside which you research based on any type of >new information other than the score. > >So, as so often, you ask: do I expand/scrap the framework (in this case, >alpha-beta), or does this idea go into the scrap pile (or revisit later list)? >If your goal is something which works, you'll probably unfortunately find that a >lot of your more interesting ideas fall into the second category ;-) > >Anyway, good luck with the project. > >Cheers, >Vas So many good ideas have to be discarded simply because they won't work. From one of David Eddings' books. anthony
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.