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Subject: Re: Does this position blow up your program?

Author: Martin Giepmans

Date: 08:48:33 12/26/02

Go up one level in this thread


On December 25, 2002 at 12:31:17, John Lowe wrote:

>On December 25, 2002 at 11:55:24, Martin Giepmans wrote:
>
>>On December 25, 2002 at 11:27:52, Martin Giepmans wrote:
>>
>>>On December 25, 2002 at 08:33:00, John Lowe wrote:
>>>
>>>>On December 25, 2002 at 08:11:55, Martin Giepmans wrote:
>>>>
>>>>>On December 25, 2002 at 00:51:57, John Lowe wrote:
>>>>>
>>>>>>On December 24, 2002 at 18:11:51, Martin Giepmans wrote:
>>>>>>
>>>>>>>On December 24, 2002 at 12:32:55, John Lowe wrote:
>>>>>>>
>>>>>>>>On December 23, 2002 at 15:37:07, Martin Giepmans wrote:
>>>>>>>>
>>>>>>>>>On December 23, 2002 at 15:16:44, Mike Byrne wrote:
>>>>>>>>>
>>>>>>>>>>[d]R6R/3Q4/1Q4Q1/4Q3/2Q4Q/Q4Q2/pp1Q4/kBNN1KB1 w - - 0 1
>>>>>>>>>>
>>>>>>>>>>So far , every Palm program and Chess Tiger have fatal errors with this
>>>>>>>>>>position.  Supossedly, this is the largest number of  possible legal number of
>>>>>>>>>>moves, 218, available from one position in chess.  If you can prove this wrong,
>>>>>>>>>>you'll go down in History.
>>>>>>>>>>
>>>>>>>>>>http://www.rescon.de/Compu/schachzahl2_e.html
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>"Qd2xb2 mate!" says my program. 29 nodes calculated to find this brilliancy.
>>>>>>>>>
>>>>>>>>>It didn't blow up, the monitor didn't explode in my face, the AMD-processor
>>>>>>>>>didn't implode, even my cigarette didn't catch fire ...
>>>>>>>>>
>>>>>>>>>I must say that I find this at least a little bit disappointing ;)
>>>>>>>>>
>>>>>>>>>Martin
>>>>>>>>
>>>>>>>>Hi Martin,
>>>>>>>>
>>>>>>>>You can borrow my failure if you like.
>>>>>>>
>>>>>>>Thanks!  Do you really want it back?
>>>>>>>>
>>>>>>>>How did you manage to calculate 29 nodes before you found a mate in one?
>>>>>>>
>>>>>>>I don't know if you grinned when you wrote that.
>>>>>>>Do you mean that 29 is way too much for a mate in (only) one <grin>
>>>>>>>or do you mean that 29 is not enough?
>>>>>>>
>>>>>>>Martin
>>>>>>
>>>>>>Of course I grinned. The whole position is a party game.
>>>>>>
>>>>>>I'm trying to imagine which order you would have to evaluate moves in to have 28
>>>>>>misses before finding one of the mates.
>>>>>>
>>>>>29 nodes is the total number of nodes visited in the searchtree; even in
>>>>>the first iteration this is usually (much) more than the number of moves
>>>>>tried at the root. It probably did only a few moves at the root, found a
>>>>>mate and stopped.
>>>>>
>>>>>>My program generates little piece moves first and would have stumbled over the
>>>>>>knight mate - then it would(irrationally) have finished all the moves and
>>>>>>selected its favourite mate - which is why it crashed.....
>>>>>>
>>>>>>
>>>>>>Happy Christmas
>>>>>
>>>>>Happy Christmas too!
>>>>
>>>>DIY wants to know if it can be a Spider when it grows up.
>>>
>>>I don't think so. A real spider is much smarter.
>>>I always have a plastic spider with me when I play in tournaments.
>>>Till now it scared one operator (who suffered from arachnaphobia)
>>>but it didn't impress the engines at all.
>>>I'll have to find a better strategy ;)
>>>
>>>Martin
>>
>>Ah, I see that I misunderstood your question.
>>Your program DIY wanted to know if can be a Spider ...
>>Sure DIY! If you can ask such questions you must be quite smart already.
>>That promises a bright future!
>>
>>Advice: count your legs every day. As long as you have 8 legs
>>everything is probably OK.
>>
>>Martin
>
>At least Spider wasn't spooked by nine white queens and two connected enemy
>passed pawns.

It uses a movelist at the root (room for 400 moves, just to be safe)
but for ply 2, 3, etc there are only lists for captures.
Other moves are generated one by one.
That could help in a case like this.

>
>I wonder if it's possible to generate that position within the rules?

What was black's last move? b2, bxa2, axb2, ..?
Too complicated. I give up ....
Maybe there is a program that could help here?
In any case, if this position arose in a legal game, it must have been
a very weird game. Monkey1 - Monkey2?

Martin





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