/// <summary>
/// Initializes a new instance of the <see cref="RegularSearch"/> class.
/// </summary>
/// <param name="transpositionTable">The transposition table.</param>
/// <param name="historyTable">The history table.</param>
/// <param name="killerTable">The killer table.</param>
public RegularSearch(TranspositionTable transpositionTable, HistoryTable historyTable, KillerTable killerTable)
{
_transpositionTable = transpositionTable;
_historyTable = historyTable;
_killerTable = killerTable;
_quiescenceSearch = new QuiescenceSearch();
_patternsDetector = new PatternsDetector();
}
private void HelperTask(HelperTaskParameters param)
{
var historyTable = new HistoryTable();
var killerTable = new KillerTable();
var helperSearch = new RegularSearch(_transpositionTable, historyTable, killerTable);
killerTable.SetInitialDepth(param.InitialDepth);
helperSearch.Do(param.Color, param.Bitboard, param.InitialDepth, AIConstants.InitialAlphaValue, AIConstants.InitialBetaValue, param.Deadline, true, new AIStats());
}
/// <summary>
/// Calculates the best possible move for the specified parameters.
/// </summary>
/// <param name="color">The initial player.</param>
/// <param name="bitboard">The bitboard.</param>
/// <param name="preferredTime">Time allocated for AI.</param>
/// <param name="helperTasks">The helper tasks count (0 for single thread).</param>
/// <returns>The result of AI calculating.</returns>
public AIResult Calculate(Color color, Bitboard bitboard, float preferredTime, int helperTasks)
{
var result = new AIResult();
var colorSign = ColorOperations.ToSign(color);
var stopwatch = new Stopwatch();
int estimatedTimeForNextIteration;
var historyTable = new HistoryTable();
var killerTable = new KillerTable();
var regularSearch = new RegularSearch(_transpositionTable, historyTable, killerTable);
result.Color = color;
result.PreferredTime = preferredTime;
var deadline = preferredTime != 0 ? DateTime.Now.AddSeconds(preferredTime * 2).Ticks : DateTime.Now.AddSeconds(1).Ticks;
historyTable.Clear();
killerTable.Clear();
if (bitboard.ReversibleMoves == 0 && preferredTime > 0)
{
_transpositionTable.Clear();
}
stopwatch.Start();
do
{
result.Depth++;
killerTable.SetInitialDepth(result.Depth);
if (result.Depth >= AIConstants.MinimalDepthToStartHelperThreads)
{
for (var i = 0; i < helperTasks; i++)
{
var param = new HelperTaskParameters
{
Bitboard = new Bitboard(bitboard),
Color = color,
Deadline = deadline,
InitialDepth = result.Depth
};
Task.Run(() => HelperTask(param));
}
}
var stats = new AIStats();
var score = colorSign * regularSearch.Do(color, new Bitboard(bitboard), result.Depth, AIConstants.InitialAlphaValue, AIConstants.InitialBetaValue, deadline, false, stats);
if (DateTime.Now.Ticks <= deadline)
{
result.PVNodes = GetPVNodes(bitboard, color);
result.Score = score;
OnThinkingOutput?.Invoke(this, new ThinkingOutputEventArgs(result));
}
else
{
result.Depth--;
_transpositionTable.Clear();
}
result.Stats = stats;
result.Ticks = stopwatch.Elapsed.Ticks;
estimatedTimeForNextIteration = (int)stopwatch.Elapsed.TotalMilliseconds * result.Stats.BranchingFactor;
}while (estimatedTimeForNextIteration < preferredTime * 1000 &&
result.Depth < AIConstants.MaxDepth &&
Math.Abs(result.Score) != AIConstants.MateValue);
return(result);
}
