Author: Bo Persson
Date: 14:27:25 06/16/03
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On June 15, 2003 at 10:15:31, Sune Fischer wrote: > >>I guess the programs that use this method, like Crafty, also have a special >>get_out_of_check() move generator. When in check the possible moves are very >>limited: >> >>- capture the checking piece (if it is only one) >>- put another piece between the king and the checker (if it is a slider) >>- move the king away from the attacked ray >>- now you are really desperate - try an en passant capture! >> >>Most of these will not move you into (another) check, so it will reduce the >>cost. > >Exactly. > >>>Secondly you need to know you are in check so you can _extend_. >>> >> >>or you can extend on moving out of check. You know you are there because you use >>the special get_out_of_check routine. :-) > >You've lost me. >If you don't check for anyhing you don't know anything. Of course you have to check if the opponents move is checking your king. What you can avoid is checking if *your* move checks your *own* king. That will be revealed when it is immediately captured. >How it is possible to apply an extension even for the get_out_of_check? >How will you know to call a get_out_of_check routine if you don't know you're in >check? > >Suppose you are in check, you happen to search the capture of the checking piece >first. Now you are out of check and the position is perfectly legal. You've now >searched this move without extending it. How do you fix that? > >-S. > >> >> >> >>Bo Persson >>bop2@telia.com
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