Author: Gerd Isenberg
Date: 13:39:51 03/24/04
Go up one level in this thread
>I guess a third fill is necessary to solve that...
>(or something smarter)
>
>Eg. to look whether the set of all safe squares reachable in one bishop move is
>equal to the set of safe squares reachable in three bishop moves.
>Also forgotten to pass the propagator (empty, allowed or ~tabu) to the kogge
>stone attack getter or filler.
>
>BitBoard getTrappedBishopSquares(BitBoard potb, BitBoard allowed, int n)
>{
> BitBoard trappedBishopSquares = 0;
> potb &= allowed; // exclude tabu squares from the potential trapped
> while ( potb ) {
> BitBoard fromBB = potb & -potb;
> BitBoard inOne = fillBishopAttacks(fromBB, allowed) & allowed;
> BitBoard inTwo = fillBishopAttacks(inOne, allowed) & allowed;
> BitBoard inThree = fillBishopAttacks(inTwo, allowed) & allowed;
> // tag all reachable in up to three moves as done
> potb &= ~(fromBB|inOne|inTwo|inThree);
> if ( inOne == inThree && popCount(inOne) < n )
> trappedBishopSquares |= (ssqs|inOne|inTwo);
> }
> return trappedBishopSquares;
>}
>
>Without any warranty ;-)
yes, the propagator (own none movable pawns) should be decoupled from the
allowed/tabu set...
// fixed is subset of tabu (may be equal), the set of all own blocked
// and backward pawns.
// tabu may contain enemy pawn attacks which don't terminate the attack ray
BitBoard getTrappedBishopSquares(BitBoard fixed, BitBoard tabu, int n)
{
BitBoard trappedBishopSquares = 0;
BitBoard potb = ~tabu;
while ( potb ) {
BitBoard fromBB = potb & -potb;
BitBoard inOne = fillBishopAttacks(fromBB, ~fixed) & ~tabu;
BitBoard inTwo = fillBishopAttacks(inOne, ~fixed) & ~tabu;
BitBoard inThree = fillBishopAttacks(inTwo, ~fixed) & ~tabu;
// tag all reachable in up to three moves as done
potb &= ~(fromBB|inOne|inTwo|inThree);
if ( inOne == inThree && popCount(inOne) < n )
trappedBishopSquares |= (fromBB|inOne|inTwo);
}
return trappedBishopSquares;
}
>
>Cheers,
>Gerd
This page took 0.01 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.