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   Author  Topic: Trap evaluation in Bomb  (Read 1546 times)
fotland
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Trap evaluation in Bomb
« on: Feb 11th, 2007, 7:10pm »
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First, I never evaluate a position in the middle of a push.  Since the next step is forced, I always extend the search one ply instead of evaluating when a piece has just been pushed.
 
Notation: x-empty, e-enemy, the side doing the capture, f-friend, the piece being captured, p a spot where a piece can be pulled, w-weak enemy piece that has to get out of the way.  A capital letter indicates the trap location.  The patterns are presented in a line but can be matched bent.
 
In all cases the enemy piece doing the capture might need to be unfrozen first.  This can add 0, 1, or 2 steps (uf).
 
In many cases an enemy piece can be on the trap and must move off first (on).  This can add 0, 1, or 2 steps.  1 step if an enemy can move away.  2 steps to push away a friend.  It could be more, but I stop analyzing at 2 steps.
 
Traps with zero friendly pieces adjacent:
 
Xef 4 + uf + on, and check that e can move sideways or move onto trap without suicide.
 
Xwfe - close e must move out of the way.  5 + uf + on, and check that close e not frozen.
 
Xxfe - 4 + uf + on, and check that e doesn't get frozen when it moves to f spot
 
Xxfxe - 5 + uf + on, and check two spots that e dosn't get frozen on the way
 
Epf - 3 + uf
 
Xpf - 3 + uf + on
 
Xxef, Xxxfe - 6 + uf + on
 
Traps with one friendly piece adjacent
 
ePf - 1 step
 
Xfe - 2 + uf + on
 
Ef - 2 + uf, and check if there is empty square to move to
 
Ffe - 2 + uf
 
Xfxe - 3 + uf + on, and check if e won't freeze after move
 
Ffxe - 3 + uf, and check if e won't freeze
 
Ffpe - 1
 
Xfwe - 4 + on + uf, and check if e won't freeze
 
Xfwxe - 5 + on + uf
 
Xffe - 4 + on + uf, check if e will freeze
 
Fffe - 4 + uf
 
Xfxxe - 4 + uf, and check that right x is not unsafe trap
 
exXf - 4 + uf, and check that trap is safe
 
eXf - 3 + uf + on, and check that e doesn't suicide
 
 
Traps with two friendly pieces adjacent
 
efXfe - 4 + on.  choose to trap the bigger piece
 
I think this is all of them.
« Last Edit: Feb 12th, 2007, 10:13pm by fotland » IP Logged
chessandgo
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Re: Trap evaluation in Bomb
« Reply #1 on: Feb 12th, 2007, 5:57am »
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I've been trying to generate capture moves lately, I'm not done yet but I certainly would be very interested to see an extensive list of capture patterns.
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IdahoEv
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Re: Trap evaluation in Bomb
« Reply #2 on: Feb 12th, 2007, 1:53pm »
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I would be interested to see them as well.
 
Thank you for this interesting and informative series of posts.  Out of curiosity, what brought them on?
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fotland
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Re: Trap evaluation in Bomb
« Reply #3 on: Feb 12th, 2007, 8:54pm »
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on Feb 12th, 2007, 1:53pm, IdahoEv wrote:
I would be interested to see them as well.
 
Thank you for this interesting and informative series of posts.  Out of curiosity, what brought them on?

 
 
Fritzlein's post: One wonders how many other efficiency-boosting tricks you casually integrated into your code, based on ideas the rest of us wouldn't hit upon in years.  
 
But then I decided I have to explain the basics before I can explain the mate search, etc.
« Last Edit: Feb 12th, 2007, 8:54pm by fotland » IP Logged
chessandgo
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Re: Trap evaluation in Bomb
« Reply #4 on: Feb 20th, 2007, 9:35am »
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Thanks for taking the time typing all these patterns.
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