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search.cpp
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search.cpp
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/*===========================================================================
search.cpp - Copyright (C) 1993-2005 by Don Cross
Contains min-max search algorithms with alpha-beta pruning for chess.
This is the "brains" of Chenard's computer player.
===========================================================================*/
#include <stdio.h>
#include <string.h>
#include "chess.h"
#include "lrntree.h"
#include "profiler.h"
#define ESCAPE_CHECK_DEPTH (gene.v[0])
#define MAX_CHECK_DEPTH (gene.v[1])
#define HASH_HIST_MAX (gene.v[2])
#define HASH_HIST_FUNC(h,d) (gene.v[3])
#define DEBUG_BOARD_CORRUPTION 0
ComputerChessPlayer::ComputerChessPlayer ( ChessUI &ui ):
ChessPlayer ( ui ),
minlevel ( 0 ),
maxlevel ( 3 ),
level ( 0 ),
maxCheckDepth ( MAX_CHECK_DEPTH ),
visited ( 0 ),
evaluated ( 0 ),
generated ( 0 ),
searchBias ( 1 ),
extendSearchFlag ( false ),
computerPlayingWhite ( false ),
expectedScorePrev ( 0 ),
expectedScoreNow ( 0 ),
revertTimeLimit ( 0 ),
searchType ( CCPST_DEPTH_SEARCH ),
maxNodesEvaluated ( 0 ),
searchAborted ( false ),
stopTime ( 0 ),
timeLimit ( 0 ),
timeCheckCounter ( 0 ),
timeCheckLimit ( 100 ),
prevTime ( 0 ),
whiteEval ( &ComputerChessPlayer::WhiteMidgameEval ),
blackEval ( &ComputerChessPlayer::BlackMidgameEval ),
eachBestPathCount ( 0 ),
eachBestPath (new BestPath[MAX_MOVES]),
nextBestPath(new BestPath[MAX_BESTPATH_DEPTH + 8]),
expectedNextBoardHash ( 0 ),
prevCompletedLevel ( 0 ),
moveOrder_depth ( 0 ),
moveOrder_bestPathFlag ( 0 ),
hitMaxHistory ( false ),
whiteHist ( new SCORE [4096] ),
blackHist ( new SCORE [4096] ),
openingBookSearchEnabled ( true ),
trainingEnabled ( true ),
allowResignation ( false ),
enableMoveDisplayFlag ( true ),
resignThreshold ( 1200 ),
firstTimeChooseEval ( true ),
KingPosTable ( KingPosTableQR ),
oppTimeInstance ( false ),
oppTimeEnable ( false ),
blunderAlertInstance(false),
immediateSingularMove(true)
{
rootml.num = 0;
ResetHistoryBuffers();
memset(&predictedOppMove, 0, sizeof(predictedOppMove));
memset(&moveOrder_xposBestMove, 0, sizeof(moveOrder_xposBestMove));
}
ComputerChessPlayer::~ComputerChessPlayer()
{
delete[] whiteHist;
whiteHist = 0;
delete[] blackHist;
blackHist = 0;
delete[] eachBestPath;
eachBestPath = 0;
delete[] nextBestPath;
nextBestPath = 0;
}
/*static*/ void ComputerChessPlayer::LazyInitXposTable()
{
if (!XposTable)
{
// Create a default 1MB transposition table.
XposTable = new TranspositionTable(1);
}
}
static void InsertPrediction (
ChessBoard &board,
BestPath &path,
ChessUI &userInterface )
{
if ( board.GetCurrentPlyNumber() >= 2 && !board.HasBeenEdited() )
{
BestPath pastPath = path;
ChessBoard pastBoard;
int stopPly = board.GetCurrentPlyNumber() - 2;
UnmoveInfo unmove;
int ply = pastPath.depth;
int depthIncrease = 2;
if ( ply + 2 >= MAX_BESTPATH_DEPTH )
{
ply = MAX_BESTPATH_DEPTH - 3;
depthIncrease = 0;
}
for ( ply=pastPath.depth; ply>=0; --ply )
pastPath.m[ply+2] = pastPath.m[ply];
for ( ply=0; ply<stopPly; ++ply )
{
Move pastMove = board.GetPastMove(ply);
pastBoard.MakeMove (pastMove, unmove);
}
pastPath.m[0] = board.GetPastMove(ply++);
pastPath.m[0].score = pastPath.m[2].score; // so that correct score is displayed
pastPath.m[1] = board.GetPastMove(ply);
pastPath.depth += depthIncrease;
userInterface.DisplayBestPath ( pastBoard, pastPath );
}
else
userInterface.DisplayBestPath ( board, path );
}
static int NumPiecesOnGivenColor (
const SQUARE *board,
SQUARE pieceMask,
int colorBit /*white=1, black=0*/ )
{
// search board for given piece(s)
int counter = 0;
for ( int y=OFFSET(2,2); y <= OFFSET(2,9); y += NORTH )
{
for ( int x=0; x<8; x++ )
{
int ofs = x+y;
if ( (ofs&1)==colorBit && (board[ofs]&pieceMask) )
++counter;
}
}
return counter;
}
static inline int NumPiecesOnWhite (
const SQUARE *board,
SQUARE pieceMask )
{
return NumPiecesOnGivenColor ( board, pieceMask, 1 );
}
static inline int NumPiecesOnBlack (
const SQUARE *board,
SQUARE pieceMask )
{
return NumPiecesOnGivenColor ( board, pieceMask, 0 );
}
void ComputerChessPlayer::ChooseEvalFunctions ( ChessBoard &board )
{
// Determine from the chess board which side we are.
// Then try to open the appropriate gene file.
// If that file exists, load the gene into this player.
if ( firstTimeChooseEval )
{
firstTimeChooseEval = false;
const char *geneFilename = board.WhiteToMove() ? "white.gen" : "black.gen";
if ( gene.load(geneFilename) )
{
char message [128];
sprintf ( message, "%s has been loaded.", geneFilename );
userInterface.NotifyUser ( message );
SetTrainingEnable ( false ); // don't want to pollute the experience tree
}
else
gene.reset();
}
INT16 *inv = board.inventory;
// If either side has a lone king, and the other
// has rook(s) and/or queen(s) use endgame eval #1.
// Also use if lone king vs king and two bishops.
if ( inv [WP_INDEX] == 0 &&
inv [WN_INDEX] == 0 &&
inv [WB_INDEX] == 0 &&
inv [WR_INDEX] == 0 &&
inv [WQ_INDEX] == 0 &&
(inv [BR_INDEX] + inv [BQ_INDEX] > 0 || inv[BB_INDEX] + inv[BN_INDEX] >= 2) )
{
whiteEval = &ComputerChessPlayer::EndgameEval1;
blackEval = &ComputerChessPlayer::EndgameEval1;
// Figure out which king position table to use, and thus
// which corners we want to drive enemy king toward...
KingPosTable = KingPosTableQR;
if ( inv[BR_INDEX]+inv[BQ_INDEX]==0 && inv[BB_INDEX]>0 )
{
if ( NumPiecesOnBlack(board.board,BB_MASK) == 0 )
KingPosTable = KingPosTableBW;
else if ( NumPiecesOnWhite(board.board,BB_MASK) == 0 )
KingPosTable = KingPosTableBB;
}
}
else if ( inv [BP_INDEX] == 0 &&
inv [BN_INDEX] == 0 &&
inv [BB_INDEX] == 0 &&
inv [BR_INDEX] == 0 &&
inv [BQ_INDEX] == 0 &&
(inv [WR_INDEX] + inv[WQ_INDEX] > 0 || inv[WB_INDEX] + inv[WN_INDEX] >= 2) )
{
whiteEval = &ComputerChessPlayer::EndgameEval1;
blackEval = &ComputerChessPlayer::EndgameEval1;
// Figure out which king position table to use, and thus
// which corners we want to drive enemy king toward...
// Figure out which king position table to use, and thus
// which corners we want to drive enemy king toward...
KingPosTable = KingPosTableQR;
if ( inv[WR_INDEX]+inv[WQ_INDEX]==0 && inv[WB_INDEX]>0 )
{
if ( NumPiecesOnBlack(board.board,WB_MASK) == 0 )
KingPosTable = KingPosTableBW;
else if ( NumPiecesOnWhite(board.board,WB_MASK) == 0 )
KingPosTable = KingPosTableBB;
}
}
else
{
// Use the default midgame evaluator...
whiteEval = &ComputerChessPlayer::WhiteMidgameEval;
blackEval = &ComputerChessPlayer::BlackMidgameEval;
}
}
void ComputerChessPlayer::ResetHistoryBuffers()
{
for ( int i=0; i<4096; ++i )
whiteHist[i] = blackHist[i] = 0;
LazyInitXposTable();
XposTable->reset();
}
void ComputerChessPlayer::setResignThreshold(unsigned _resignThreshold)
{
if ( _resignThreshold < 400 )
resignThreshold = 400;
else if ( _resignThreshold > 20000 )
resignThreshold = 20000;
else
resignThreshold = _resignThreshold;
}
INT32 TimeSearchStarted = 0;
ComputerChessPlayer *ComputerPlayerSearching = 0;
void ComputerChessPlayer::InformResignation()
{
// The opponent has resigned, so it is time to abort any pondering that may be in progress.
userInterface.oppTime_abortSearch();
}
bool ComputerChessPlayer::GetMove (
ChessBoard &board,
Move &bestmove,
INT32 &timeSpent )
{
PROFILER_ENTER(PX_SEARCH);
timeSpent = 0;
//---------------------------------------------------------------------
// Before doing anything else, see if we need to continue
// thinking on the opponent's turn.
if ( oppTimeEnable && !oppTimeInstance && searchType == CCPST_TIMED_SEARCH )
{
bool oppTime = userInterface.oppTime_finishThinking (
board,
timeLimit,
timeSpent,
bestmove,
predictedOppMove );
if ( oppTime )
{
if ( enableMoveDisplayFlag )
userInterface.DisplayMove ( board, bestmove );
return true;
}
}
cancelPredictedOpponentMove();
INT32 timeBefore = TimeSearchStarted = ChessTime();
ComputerPlayerSearching = this;
if ( searchType == CCPST_TIMED_SEARCH )
{
prevTime = timeBefore;
stopTime = prevTime + timeLimit;
timeCheckCounter = 0;
}
searchAborted = false;
hitMaxHistory = false;
userInterface.ComputerIsThinking ( true, *this );
ChooseEvalFunctions ( board );
XposTable->startNewSearch();
if ( board.WhiteToMove() )
GetWhiteMove ( board, bestmove );
else
GetBlackMove ( board, bestmove );
INT32 timeAfter = ChessTime();
timeSpent = timeAfter - timeBefore;
ComputerPlayerSearching = 0;
userInterface.ComputerIsThinking ( false, *this );
if ( enableMoveDisplayFlag )
userInterface.DisplayMove ( board, bestmove );
userInterface.ReportComputerStats (
timeSpent,
visited,
evaluated,
generated,
level+1,
visnodes,
gennodes );
FindPrevBestPath ( bestmove );
expectedNextBoardHash = 0; // will never match any board hash
static int NextBoardTotal=0, NextBoardHit1=0, NextBoardHit2=0;
bool havePredictedOppMove = false;
if ( currentBestPath.depth > 1 )
{
++NextBoardTotal;
// Keep hash code of expected board position if opponent makes the
// move we think he will make. This helps us to know whether we
// can recycle best path information on our next search.
UnmoveInfo unmove[2];
if ( board.isLegal(bestmove) )
{
++NextBoardHit1;
board.MakeMove ( bestmove, unmove[0] );
if ( board.isLegal(currentBestPath.m[1]) )
{
++NextBoardHit2;
havePredictedOppMove = true;
predictedOppMove = currentBestPath.m[1];
board.MakeMove ( predictedOppMove, unmove[1] );
expectedNextBoardHash = board.Hash();
board.UnmakeMove ( currentBestPath.m[1], unmove[1] );
}
board.UnmakeMove ( bestmove, unmove[0] );
}
}
PROFILER_EXIT();
if ( allowResignation )
{
if ( board.WhiteToMove() &&
bestmove.score <= -resignThreshold )
{
return false; // resign
}
else if ( board.BlackToMove() &&
bestmove.score >= resignThreshold )
{
return false; // resign
}
}
//----------- thinking on opponent's time -----------------------
if ( havePredictedOppMove )
{
if ( oppTimeEnable && !oppTimeInstance && timeSpent>=100 )
{
userInterface.oppTime_startThinking (
board,
bestmove,
predictedOppMove );
}
}
else
{
predictedOppMove.source = predictedOppMove.dest = 0;
predictedOppMove.score = 0;
}
return true; // keep on playing!
}
void ComputerChessPlayer::GetWhiteMove (
ChessBoard &board,
Move &bestmove )
{
computerPlayingWhite = true;
moveOrder_bestPathFlag = false;
board.GenWhiteMoves ( rootml, this );
bestmove = rootml.m[0]; // just in case!
gennodes[0] = generated = rootml.num;
visited = evaluated = 0;
int i;
for ( i=0; i < NODES_ARRAY_SIZE; i++ )
visnodes[i] = gennodes[i] = 0;
for ( i=0; i < 4096; i++ )
{
whiteHist[i] /= 2;
blackHist[i] /= 2;
}
if ( rootml.num == 1 && isEnabledImmediateSingularMove() )
{
// If we are doing a blunder alert analysis,
// we really need to know the score for the position
// even if there is only a single move.
// Otherwise, don't waste time thinking when there is no choice.
if (!blunderAlert_QueryInstanceFlag())
{
// Always fill out some kind of valid best path before leaving.
currentBestPath.depth = 0;
currentBestPath.m[0] = rootml.m[0];
currentBestPath.m[0].score = 0; // we have no idea how good the move is
return; // only one legal move exists, so just do it!
}
}
if ( openingBookSearchEnabled && WhiteOpening ( board, bestmove ) )
{
userInterface.ReportSpecial ( "opening" );
// Always fill out some kind of valid best path before leaving.
currentBestPath.depth = 0;
currentBestPath.m[0] = bestmove;
return; // We found a groovy opening move
}
char buffer [64];
if ( FindEndgameDatabaseMove (board, bestmove) )
{
sprintf ( buffer, "endgame (%6d)", int(bestmove.score) );
userInterface.ReportSpecial ( buffer );
if ( bestmove.score >= WON_FOR_WHITE &&
bestmove.score < WHITE_WINS - WIN_DELAY_PENALTY &&
!isBackgroundThinker() )
{
int plies = (WHITE_WINS - long(bestmove.score)) / WIN_DELAY_PENALTY;
userInterface.PredictMate (1 + plies/2);
}
// Always fill out some kind of valid best path before leaving.
currentBestPath.depth = 0;
currentBestPath.m[0] = bestmove;
return;
}
LearnTree tree;
if ( (searchType == CCPST_TIMED_SEARCH) && trainingEnabled &&
tree.familiarPosition ( board, bestmove, timeLimit, rootml ) )
{
sprintf ( buffer, "experience (%6d)", int(bestmove.score) );
userInterface.ReportSpecial ( buffer );
// Always fill out some kind of valid best path before leaving.
currentBestPath.depth = 0;
currentBestPath.m[0] = bestmove;
return; // We found a move we know is best from a previous (longer) search
}
// See if we can recycle best path info from the previous move's search.
UINT32 hash = board.Hash();
int startLevel = minlevel;
if ( hash==expectedNextBoardHash &&
currentBestPath.depth>=2 && prevCompletedLevel>1 )
{
// Strip the top two plies because they are in the past!
for ( i=2; i <= currentBestPath.depth; i++ )
currentBestPath.m[i-2] = currentBestPath.m[i];
currentBestPath.depth -= 2;
eachBestPathCount = 1;
eachBestPath[0] = currentBestPath;
startLevel = prevCompletedLevel - 1;
rootml.SendToFront ( currentBestPath.m[0] );
bestmove = rootml.m[0];
}
else
{
eachBestPathCount = 0;
currentBestPath.depth = 0;
}
nextBestPath[0].depth = 0;
prevCompletedLevel = 0;
expectedScorePrev = NEGINF;
expectedScoreNow = NEGINF;
revertTimeLimit = 0;
const INT32 startThinkTime = ChessTime();
for ( level=startLevel; !searchAborted && level <= maxlevel; level++ )
{
WhiteSearchRoot ( board, bestmove );
if ( !searchAborted )
prevCompletedLevel = level;
if ( bestmove.score >= WON_FOR_WHITE )
break; // We have found a forced win!
if ( bestmove.score <= WON_FOR_BLACK )
break; // Time to give up - no deeper search will improve things.
expectedScorePrev = expectedScoreNow;
}
const INT32 actualThinkTime = ChessTime() - startThinkTime;
if ( bestmove.score >= WON_FOR_WHITE &&
bestmove.score < WHITE_WINS - WIN_DELAY_PENALTY &&
!isBackgroundThinker() )
{
// If we get here, it means we predict a forced checkmate
// for White! We can calculate how many moves it will take
// using the score.
int plies = (WHITE_WINS - long(bestmove.score)) / WIN_DELAY_PENALTY;
userInterface.PredictMate (1 + plies/2);
}
if ( revertTimeLimit )
{
SetTimeLimit (revertTimeLimit);
revertTimeLimit = 0;
}
if ( searchType==CCPST_TIMED_SEARCH && trainingEnabled )
{
tree.rememberPosition ( board, bestmove, actualThinkTime, evaluated, 1, 0 );
}
}
void ComputerChessPlayer::GetBlackMove (
ChessBoard &board,
Move &bestmove )
{
computerPlayingWhite = false;
moveOrder_bestPathFlag = false;
board.GenBlackMoves ( rootml, this ); // Generate sorted list of legal moves
bestmove = rootml.m[0]; // just in case!
gennodes[0] = generated = rootml.num;
visited = evaluated = 0;
int i;
for ( i=0; i < NODES_ARRAY_SIZE; i++ )
visnodes[i] = gennodes[i] = 0;
for ( i=0; i < 4096; i++ )
{
whiteHist[i] /= 2;
blackHist[i] /= 2;
}
if ( rootml.num == 1 && isEnabledImmediateSingularMove() )
{
// If we are doing a blunder alert analysis,
// we really need to know the score for the position
// even if there is only a single move.
// Otherwise, don't waste time thinking when there is no choice.
if (!blunderAlert_QueryInstanceFlag())
{
// Always fill out some kind of valid best path before leaving.
currentBestPath.depth = 0;
currentBestPath.m[0] = rootml.m[0];
currentBestPath.m[0].score = 0; // we have no idea how good the move is
return; // only one legal move exists, so just do it!
}
}
if ( openingBookSearchEnabled && BlackOpening ( board, bestmove ) )
{
userInterface.ReportSpecial ( "opening" );
// Always fill out some kind of valid best path before leaving.
currentBestPath.depth = 0;
currentBestPath.m[0] = bestmove;
return; // We found a groovy opening move
}
char buffer [64];
if ( FindEndgameDatabaseMove (board, bestmove) )
{
sprintf ( buffer, "endgame (%6d)", int(bestmove.score) );
userInterface.ReportSpecial ( buffer );
if ( bestmove.score <= WON_FOR_BLACK &&
bestmove.score > BLACK_WINS + WIN_DELAY_PENALTY &&
!isBackgroundThinker() )
{
int plies = (long(bestmove.score) - BLACK_WINS) / WIN_DELAY_PENALTY;
userInterface.PredictMate (1 + plies/2);
}
// Always fill out some kind of valid best path before leaving.
currentBestPath.depth = 0;
currentBestPath.m[0] = bestmove;
return;
}
LearnTree tree;
if ( searchType==CCPST_TIMED_SEARCH && trainingEnabled &&
tree.familiarPosition ( board, bestmove, timeLimit, rootml ) )
{
sprintf ( buffer, "experience (%6d)", int(bestmove.score) );
userInterface.ReportSpecial ( buffer );
// Always fill out some kind of valid best path before leaving.
currentBestPath.depth = 0;
currentBestPath.m[0] = bestmove;
return; // We found a move we know is best from a previous (longer) search
}
// See if we can recycle best path info from the previous move's search.
UINT32 hash = board.Hash();
int startLevel = minlevel;
if ( hash==expectedNextBoardHash &&
currentBestPath.depth>=2 && prevCompletedLevel>1 )
{
// Strip the top two plies because they are in the past!
for ( i=2; i <= currentBestPath.depth; i++ )
currentBestPath.m[i-2] = currentBestPath.m[i];
currentBestPath.depth -= 2;
eachBestPathCount = 1;
eachBestPath[0] = currentBestPath;
startLevel = prevCompletedLevel - 1;
rootml.SendToFront ( currentBestPath.m[0] );
bestmove = rootml.m[0];
}
else
{
eachBestPathCount = 0;
currentBestPath.depth = 0;
}
nextBestPath[0].depth = 0;
prevCompletedLevel = 0;
expectedScorePrev = POSINF;
expectedScoreNow = POSINF;
revertTimeLimit = 0;
const INT32 startThinkTime = ChessTime();
for ( level=startLevel; !searchAborted && level <= maxlevel; level++ )
{
BlackSearchRoot ( board, bestmove );
if ( !searchAborted )
prevCompletedLevel = level;
if ( bestmove.score <= WON_FOR_BLACK )
break;
if ( bestmove.score >= WON_FOR_WHITE )
break;
expectedScorePrev = expectedScoreNow;
}
const INT32 actualThinkTime = ChessTime() - startThinkTime;
if ( bestmove.score <= WON_FOR_BLACK &&
bestmove.score > BLACK_WINS + WIN_DELAY_PENALTY &&
!isBackgroundThinker() )
{
// If we get here, it means we predict a forced checkmate
// for Black! We can calculate how many moves it will take
// using the score.
int plies = (long(bestmove.score) - BLACK_WINS) / WIN_DELAY_PENALTY;
userInterface.PredictMate (1 + plies/2);
}
if ( revertTimeLimit )
{
SetTimeLimit (revertTimeLimit);
revertTimeLimit = 0;
}
if ( searchType==CCPST_TIMED_SEARCH && trainingEnabled )
{
tree.rememberPosition ( board, bestmove, actualThinkTime, evaluated, 1, 0 );
}
}
void ComputerChessPlayer::FindPrevBestPath ( Move m )
{
// This function tries to find the previous top-level move
// in the best path table and copy it into currentBestPath.
for ( int i=0; i < eachBestPathCount; i++ )
{
if ( eachBestPath[i].depth > 0 && eachBestPath[i].m[0] == m )
{
currentBestPath = eachBestPath[i];
return;
}
}
currentBestPath.depth = 0; // keep search from using best path
}
BestPath *ComputerChessPlayer::SaveTLMBestPath ( Move move )
{
// Try to find move in existing TLM BestPaths...
bool found = false;
int i;
for ( i=0; !found && i < eachBestPathCount; i++ )
if ( eachBestPath[i].m[0] == move )
found = true;
if (!found)
{
// Need to add a new one!
if ( eachBestPathCount >= MAX_MOVES )
{
ChessFatal ( "BestPath top-level-move overflow!" );
return 0;
}
i = eachBestPathCount++;
}
eachBestPath[i] = nextBestPath[1];
eachBestPath[i].m[0] = move;
return &eachBestPath[i];
}
void ComputerChessPlayer::FoundBestMove (
Move bestmove,
int depth )
{
if ( depth < MAX_BESTPATH_DEPTH-1 )
{
// Insert the bestmove found at this depth...
nextBestPath[depth].m[depth] = bestmove;
#if DEBUG_BEST_PATH
static long bestPathCounter = 0;
nextBestPath[depth].counter[depth] = ++bestPathCounter;
#endif
// Copy best path from layer below to this layer.
int copyDepth =
nextBestPath[depth].depth =
nextBestPath[depth+1].depth;
if ( copyDepth >= MAX_BESTPATH_DEPTH-1 )
copyDepth = MAX_BESTPATH_DEPTH-1;
Move *source = &nextBestPath[depth+1].m[0];
Move *dest = &nextBestPath[depth].m[0];
for ( int d=depth+1; d <= copyDepth; d++ )
{
dest[d] = source[d];
#if DEBUG_BEST_PATH
nextBestPath[depth].counter[d] = nextBestPath[depth+1].counter[d];
#endif
}
}
}
SCORE ComputerChessPlayer::WhiteSearchRoot (
ChessBoard &board,
Move &bestmove )
{
#if DEBUG_BOARD_CORRUPTION
UINT32 bcopy [144];
memcpy ( bcopy, board.board, sizeof(bcopy) );
#endif
SCORE score;
SCORE bestscore = NEGINF;
SCORE alpha = MIN_WINDOW; // Best so far for White
SCORE beta = MAX_WINDOW; // Best so far for Black
hashPath[0] = board.Hash();
int i;
Move *move;
UnmoveInfo unmove;
for ( i=0, move=&rootml.m[0];
!searchAborted && i < rootml.num;
i++, move++ )
{
// If this isn't the first move we are considering, and it
// is a definite loser, just skip it!
if ( i>0 && move->score <= WON_FOR_BLACK )
continue;
++visited;
++visnodes[0];
if ( level > 1 )
userInterface.DisplayCurrentMove ( board, *move, level );
FindPrevBestPath ( *move );
if (!this->blunderAlert_QueryInstanceFlag()) // band-aid to prevent thread-safety problem with static variables
{
userInterface.DebugPly ( 0, board, *move );
}
board.MakeWhiteMove ( *move, unmove, false, false );
if ( level > 0 )
{
score = BlackSearch ( board, 1, alpha, beta, true );
if ( !searchAborted )
move->score = score;
}
else
{
score = move->score = BlackQSearch ( board, 1, alpha, beta, true );
}
board.UnmakeWhiteMove ( *move, unmove );
BestPath *path = 0;
if ( !searchAborted )
path = SaveTLMBestPath ( *move );
if ( searchAborted )
{
if ( i > 0 )
{
// Invalidate this and all the remaining moves,
// to keep search bias from picking from them...
while ( i < rootml.num )
rootml.m[i++].score = NEGINF;
}
}
else
{
if ( score > bestscore )
{
bestmove = *move;
expectedScoreNow = bestscore = score;
userInterface.DisplayBestMoveSoFar ( board, bestmove, level );
if ( path )
{
if ( oppTimeInstance )
InsertPrediction ( board, *path, userInterface );
else
userInterface.DisplayBestPath ( board, *path );
}
}
}
if ( score > alpha )
alpha = score;
}
rootml.WhiteSort();
userInterface.DebugExit ( 0, board, bestscore );
#if DEBUG_BOARD_CORRUPTION
if ( memcmp(bcopy,board.board,sizeof(bcopy)) != 0 )
ChessFatal ("Board corruption found in WhiteSearchRoot");
#endif
return bestscore;
}
SCORE ComputerChessPlayer::BlackSearchRoot (
ChessBoard &board,
Move &bestmove )
{
#if DEBUG_BOARD_CORRUPTION
UINT32 bcopy [144];
memcpy ( bcopy, board.board, sizeof(bcopy) );
#endif
SCORE score;
SCORE bestscore = POSINF;
SCORE alpha = MIN_WINDOW; // Best so far for White
SCORE beta = MAX_WINDOW; // Best so far for Black
hashPath[0] = board.Hash();
int i;
Move *move;
UnmoveInfo unmove;
for ( i=0, move=&rootml.m[0];
!searchAborted && i < rootml.num;
i++, move++ )
{
// If this isn't the first move we are considering, and it
// is a definite loser, just skip it!
if ( i>0 && move->score >= WON_FOR_WHITE )
continue;
++visited;
++visnodes[0];
if ( level > 1 )
userInterface.DisplayCurrentMove ( board, *move, level );
FindPrevBestPath ( *move );
if (!this->blunderAlert_QueryInstanceFlag()) // band-aid to prevent thread-safety problem with static variables
{
userInterface.DebugPly ( 0, board, *move );
}
board.MakeBlackMove ( *move, unmove, false, false );
if ( level > 0 )
{
score = WhiteSearch ( board, 1, alpha, beta, true );
if ( !searchAborted )
move->score = score;
}
else
{
score = move->score = WhiteQSearch ( board, 1, alpha, beta, true );
}
board.UnmakeBlackMove ( *move, unmove );
BestPath *path = 0;
if ( !searchAborted )
path = SaveTLMBestPath ( *move );
if ( searchAborted )
{
if ( i > 0 )
{
// Invalidate all the remaining moves, to keep search
// bias from picking from them...