Author: Uri Blass
Date: 04:38:56 06/06/03
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On June 06, 2003 at 06:06:31, Sergei S. Markoff wrote: >>the problem with the trajectories seems to be that not many people seem to >>understand what botvinnik MEANT with his trajectories. maybe >>you can tell us what YOU understood :-)) > >((: > >Botvinnik was a person with a very "wide" mind (: >I can show you some of ideas that can be used to construct working method. >For example, you can found that some chess operations includes the moving some >piece from one board region to another. It can be easily found for example in >several endgames. > >Null move doing a very bad thing in some positions. It "cuts" some of this >trajectories. For example to finish attack on opponent king we must move rook >from f1 to g3. This operation includes, for exapmle, 3 plies: f1-e1, e1-e3, >e3-g3. We need to search with Depth = 6 plies to found this operation. If we has >one or tho pawns less before performing this operation, null-move can found that >when opponent not moving we, anyway, can't do something good in 4 plies (R=2) >and it causes cut-off. > >The other problem is endgame. Is some pawn endgames we must move our king from, >say, h1 to e7. But our search is "blind". 12-ply search discovers right >trajectory, but it also discovers a lot of really stupid king movements. In some >cases it's a good idea to extend some trajectories if we can see a goal - some >pawn rams or something else. In SmarThink I tried to extend some nodes in which >we see that previous king movement is a shape with no self-intersections and >without moving to squares that can be reached by king early. This method also >need some special cut-offs to stop cathastropic tree expanding. It seems that you are talking about extending moves that seems to go for a plan. I did not know that botvinik talked about it. I read some things that botvinik said but it sounds to me too general to use them for a chess program. He never gave exact definition how to do things. I am surprised if botvinik's ideas helped you because the ideas that you talk about seem to me natural to think about them without botvinik. There are also other trivial ideas that are not implemented in most chess programs(for example the fact that programs has no knowledge about the second best move cause to absurd decisions by programs when they can use time for their move inspite of the fact that it is obvious that there is only one legal move to prevent mate). For me the main problem is to implement things without bugs and not to think about them and extending plans or calculating the exact value of the second best move at small depthes to decide about better time management are 2 ideas that were never implemented until today in movei because I decided that there are more important or more interesting things to work about them. Uri
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