When I read about the horizon effect in chess I found a scientist article (pdf) with the following position:
[d]1k6/3p4/1B6/4Pp1p/1p5R/1p4p1/pP3n2/K6n w - - bm Rxh1;
In fact it is very, very tough position for chess engines and even Sting-sf-481 can't get it.
Also it is a fact that it is rather an easy, to guess solution, position for chesspleyers.
I tried to modify Sting's code and this important for scientist position, as example giving some rigths to work at artificial inteligence can be solved in less than 2 minutes on old dual core.
This modification is very interesting (safe) and I will use it the next version.
It is a pity but I can't find this article again.
I don't think this has anything to do with horizon effect, but just that the engine does not recognize a draw pattern that is easily recognized by humans.
One evaluation heuristic here that would hugely help is to recognize the stalemate threat: there is only a single black piece that has legal moves, namely the Bishop. (That information can be an almost free side result of move generation.) Hence the Bishop is iron. The evaluation then should take note of this before counting itself rich with passers. Because an iron Bishop can pick one of the two diagonals it is on, which then discounts all your Pawns that still have to pass that diagonal. So the three passers (e,f,h) are worth zilch for as long as the Bishop is on the e1-h4 diagonal. If it is slightly smarter, it could also disregard the Knight, as it is trapped by an iron Bishop. That should be enough to get the score in the draw range.
This is knowledge of the type that would make the engine much better at Chess, but would not increase its Elo.
Note that recognition of stalemate threats also helps for recognizing rabid-Rook situations.
I think HG is not right. It is impossiblE (time) to describe such positions.
I used search and as you can see it gives wondefull effect.
It may be useful that I added in previous versions a stalemate detection to qsearch.
What about the other aspect: scientist use chess and engines to prove that an artiffical intelligence is needed (?)
Well, I just explained how it could be done without any observable slowdown.
What you consider 'wonderful' is of course by absolute standards quite awful: 2 minutes of search. To see something that materializes at 7 ply! 20 msec would have been a more reasonable result.
hgm wrote:Well, I just explained how it could be done without any observable slowdown.
What you consider 'wonderful' is of course by absolute standards quite awful: 2 minutes of search. To see something that materializes at 7 ply! 20 msec would have been a more reasonable result.
Believe me it is possible, but what about the other question:
scientists use chess and engines to prove that an A.I. is needed (?)
What exactly is the question? It seems like a statement to me.
And it also seems to me that this problem is not beyond solving by humans. So obviously no A.I. is needed to solve it. Who needs to solve Chess problems anyway?
Btw, it is debatable whether this is the correct solution. Fruit prefers something different, based on a Rabid Rook. And its score is much closer to what it should be (namely 0). And it finds it at 21 ply, 1:27 min:
hgm wrote:What exactly is the question? It seems like a statement to me.
And it also seems to me that this problem is not beyond solving by humans. So obviously no A.I. is needed to solve it. Who needs to solve Chess problems anyway?
The question is:
Scientists use chess and chess engines to prove that people need an artifical intelligence, of course not to solve chess problems.
What do you think about it?
Here are the (any) scientist (?)
BTW. The move Rxh1 solves this position, move Rxb4 maybe but I doubt.
Score, excluding ZERO and mates mens rather nothing.
hgm wrote:[Btw, it is debatable whether this is the correct solution.
Hi!
It's a position I know but pity not as for the source I got it from, somehow in my unclear remembrance about it, I think it to be connected with the name of Arpad Rusz, but maybe only because he could have brought it to this forum once upon a atime.
In my database it's called 8th step to heaven and the main variant is something like this:
[FEN "1k6/3p4/1B6/4Pp1p/1p5R/1p4p1/pP3n2/K6n w - - 0 1"]
