public static int Evaluate(BoardState board, int color, int openingPhase, int endingPhase, ulong fieldsAttackedByEnemy)
{
var enemyColor = ColorOperations.Invert(color);
var king = board.Pieces[color][Piece.King];
var kingField = BitOperations.BitScan(king);
var kingPosition = Position.FromFieldIndex(kingField);
var fieldsAroundKing = ForwardBoxPatternGenerator.GetPattern(color, kingField);
var attackedFieldsAroundKing = fieldsAroundKing & fieldsAttackedByEnemy;
var attackersCount = (int)BitOperations.Count(attackedFieldsAroundKing);
var attackersCountOpeningScore = attackersCount * EvaluationConstants.KingInDanger;
var pawnShieldOpeningScore = 0;
var openFilesNextToKingScore = 0;
if (board.CastlingDone[color])
{
var pawnsNearKing = fieldsAroundKing & board.Pieces[color][Piece.Pawn];
var pawnShield = (int)BitOperations.Count(pawnsNearKing);
pawnShieldOpeningScore = pawnShield * EvaluationConstants.PawnShield;
var openFileCheckFrom = Math.Max(0, kingPosition.X - 1);
var openFileCheckTo = Math.Min(7, kingPosition.X + 1);
for (var file = openFileCheckFrom; file <= openFileCheckTo; file++)
{
if ((FilePatternGenerator.GetPatternForFile(7 - file) & board.Pieces[color][Piece.Pawn]) == 0)
{
openFilesNextToKingScore += EvaluationConstants.OpenFileNextToKing;
}
}
}
var openingScore = pawnShieldOpeningScore + attackersCountOpeningScore + openFilesNextToKingScore;
return(TaperedEvaluation.AdjustToPhase(openingScore, 0, openingPhase, endingPhase));
}
private static (int openingScore, int endingScore) Evaluate(BoardState board, int color, int openingPhase, int endingPhase)
{
var doubledPawns = 0;
var isolatedPawns = 0;
var chainedPawns = 0;
var passingPawns = 0;
for (var file = 0; file < 8; file++)
{
var friendlyPawnsOnInnerMask = board.Pieces[color][Piece.Pawn] & FilePatternGenerator.GetPatternForFile(file);
var friendlyPawnsOnOuterMask = board.Pieces[color][Piece.Pawn] & OuterFilesPatternGenerator.GetPatternForFile(file);
var pawnsCount = BitOperations.Count(friendlyPawnsOnInnerMask);
if (pawnsCount > 1)
{
doubledPawns += (int)(pawnsCount - 1);
}
if (friendlyPawnsOnInnerMask != 0)
{
if (friendlyPawnsOnOuterMask == 0)
{
isolatedPawns += (int)BitOperations.Count(pawnsCount);
}
}
}
var pieces = board.Pieces[color][Piece.Pawn];
while (pieces != 0)
{
var lsb = BitOperations.GetLsb(pieces);
var field = BitOperations.BitScan(lsb);
pieces = BitOperations.PopLsb(pieces);
var chain = ChainPatternGenerator.GetPattern(field) & board.Pieces[color][Piece.Pawn];
if (chain != 0)
{
chainedPawns += (int)BitOperations.Count(chain);
}
if (board.IsFieldPassing(color, field))
{
passingPawns++;
}
}
var doubledPawnsOpeningScore = doubledPawns * EvaluationConstants.DoubledPawns[GamePhase.Opening];
var doubledPawnsEndingScore = doubledPawns * EvaluationConstants.DoubledPawns[GamePhase.Ending];
var isolatedPawnsOpeningScore = isolatedPawns * EvaluationConstants.IsolatedPawns[GamePhase.Opening];
var isolatedPawnsEndingScore = isolatedPawns * EvaluationConstants.IsolatedPawns[GamePhase.Ending];
var chainedPawnsOpeningScore = chainedPawns * EvaluationConstants.ChainedPawns[GamePhase.Opening];
var chainedPawnsEndingScore = chainedPawns * EvaluationConstants.ChainedPawns[GamePhase.Ending];
var passingPawnsOpeningScore = passingPawns * EvaluationConstants.PassingPawns[GamePhase.Opening];
var passingPawnsEndingScore = passingPawns * EvaluationConstants.PassingPawns[GamePhase.Ending];
var openingScore = doubledPawnsOpeningScore + isolatedPawnsOpeningScore + chainedPawnsOpeningScore + passingPawnsOpeningScore;
var endingScore = doubledPawnsEndingScore + isolatedPawnsEndingScore + chainedPawnsEndingScore + passingPawnsEndingScore;
return(openingScore, endingScore);
}
