int Search(FastBoardNode node, int searchDepth, int plyFromRoot, int alpha, int beta, int color)
{
if (searchDepth == 0)
{
using (diagnostics.quiescence.Measure())
return(QuiescenceSearch(node, plyFromRoot, alpha, beta, color));
}
List <FastMove> moves;
using (diagnostics.moveGen.Measure())
{
moves = moveCache[searchDepth];
moves.Clear();
node.AddAllPossibleMoves(moves, node.currentMove);
}
evaluationData.Prepare(node);
using (diagnostics.moveSort.Measure())
{
OrderMoves(node, moves, plyFromRoot);
}
bool isTerminal = true;
int value = int.MinValue;
foreach (var move in moves)
{
if (cancellationRequested)
{
return(0);
}
using (diagnostics.apply.Measure())
node.DoMove(move);
bool isKingVulnerable;
using (diagnostics.moveValidate.Measure())
isKingVulnerable = node.IsChecking(node.currentMove);
if (isKingVulnerable)
{
diagnostics.invalidMoves++;
using (diagnostics.apply.Measure())
node.UndoMove(move);
continue;
}
isTerminal = false;
int currentValue = -Search(node, searchDepth - 1, plyFromRoot + 1, -beta, -alpha, -color);
if (previousOrderingEnabled && plyFromRoot == 0)
{
previousScores[move] = currentValue;
}
using (diagnostics.apply.Measure())
node.UndoMove(move);
if (currentValue > value)
{
if (plyFromRoot == 0)
{
bestMoveThisIteration = move;
}
value = currentValue;
}
alpha = Math.Max(alpha, value);
if (alpha >= beta)
{
diagnostics.searchCutoff++;
break;
}
}
if (isTerminal)
{
value = color * EvaluateTerminalBoard(node, plyFromRoot);
}
return(value);
}
int QuiescenceSearch(FastBoardNode node, int plyFromRoot, int alpha, int beta, int color)
{
int eval;
evaluationData.Prepare(node);
using (diagnostics.quiescenceEval.Measure())
eval = color * EvaluateBoard(node, plyFromRoot);
if (!quiescenceSearchEnabled)
{
return(eval);
}
if (eval >= beta)
{
diagnostics.quiescenceCutoff++;
return(beta);
}
if (eval > alpha)
{
alpha = eval;
}
List <FastMove> moves;
using (diagnostics.quiescenceMoveGen.Measure())
{
moves = new List <FastMove>(10);
node.AddAllPossibleMoves(moves, node.currentMove, generateQuiet: false);
}
using (diagnostics.quiescenceMoveSort.Measure())
OrderMoves(node, moves, -1);
bool maybeTerminal = true;
int value = int.MinValue;
foreach (var move in moves)
{
if (cancellationRequested)
{
return(0);
}
using (diagnostics.quiescenceApply.Measure())
node.DoMove(move);
bool isKingVulnerable;
using (diagnostics.quiescenceMoveValidate.Measure())
isKingVulnerable = node.IsChecking(node.currentMove);
if (isKingVulnerable)
{
diagnostics.invalidMoves++;
using (diagnostics.quiescenceApply.Measure())
node.UndoMove(move);
continue;
}
maybeTerminal = false;
int currentValue = -QuiescenceSearch(node, plyFromRoot + 1, -beta, -alpha, -color);
using (diagnostics.quiescenceApply.Measure())
node.UndoMove(move);
if (currentValue > value)
{
value = currentValue;
}
alpha = Math.Max(alpha, value);
if (alpha >= beta)
{
diagnostics.quiescenceCutoff++;
break;
}
}
// No non-quiet moves were found from this position
if (maybeTerminal)
{
return(eval);
}
return(value);
}