pin and skewer

[Puspraj Jaiswal]

Flag of pin and skewer should be not checked if no bishops , no rooks and no Queen are present

[Daniel Dugovic]

Thanks for the suggestion. 95%+ of positions have a bishop, rook, or queen so I assume adding extra conditions would degrade performance:

compression/src/main/java/game/Board.java

Lines 222 to 237 in 25516fb

 private long sliderBlockers(int king) { 
     long snipers = them() & ( 
         Bitboard.rookAttacks(king, 0) & (this.rooks ^ this.queens) | 
         Bitboard.bishopAttacks(king, 0) & (this.bishops ^ this.queens)); 
  
     long blockers = 0; 
  
     while (snipers != 0) { 
         int sniper = Bitboard.lsb(snipers); 
         long between = Bitboard.BETWEEN[king][sniper] & this.occupied; 
         if (!Bitboard.moreThanOne(between)) blockers |= between; 
         snipers &= snipers - 1; 
     } 
  
     return blockers; 
 } 

Perhaps short-circuit evaluation might improve performance, for example:

(this.rooks ^ this.queens) & Bitboard.rookAttacks(king, 0)

EDIT: Technically, short-circuit evaluation doesn't work, but maybe there's a more complex way to make this work: https://stackoverflow.com/a/8759917

[Daniel Dugovic]

On my PC, the proposed change is a negative 20% speedup.