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ProgramciDusunur merged 1 commit into from
Apr 11, 2025
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A Few Adjustments And Cleaning #310

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241 changes: 154 additions & 87 deletions src/search.c
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Original file line number Diff line number Diff line change
Expand Up @@ -5,71 +5,125 @@
#include "search.h"


/* Tunable Search Parameters */

// Static Exchange Evaluation
int SEE_PIECE_VALUES[] = {100, 300, 300, 500, 1200, 0, 0};
int QS_SEE_THRESHOLD = 0;
int SEE_MOVE_ORDERING_THRESHOLD = -82;
int SEE_QUIET_THRESHOLD = -67;
int SEE_NOISY_THRESHOLD = -32;
int SEE_DEPTH = 10;

// Null Move Pruning
int NMP_DEPTH = 3;
int NMP_BASE_REDUCTION = 3;
int NMP_REDUCTION_DEPTH_DIVISOR = 3;
int NMP_EVAL_DIVISOR = 400;

// Late Move Reduction
int LMR_TABLE[2][maxPly][maxPly];
int LMR_FULL_DEPTH_MOVES = 4;
int LMR_REDUCTION_LIMIT = 3;
int DEEPER_LMR_MARGIN = 35;
double LMR_TABLE_BASE_NOISY = 0.38;
double LMR_TABLE_NOISY_DIVISOR = 3.76;
double LMR_TABLE_BASE_QUIET = 1.01;
double LMR_TABLE_QUIET_DIVISOR = 2.32;


// Late Move Pruning
int LMP_BASE = 4;
int LMP_MULTIPLIER = 3;

// Futility Pruning
int FUTILITY_PRUNING_OFFSET[] = {0, 82, 41, 20, 10, 5};
int FP_DEPTH = 5;
int FP_MARGIN = 82;

// Reverse Futility Pruning
int RFP_MARGIN = 82;
int RFP_IMPROVING_MARGIN = 65;
int RFP_DEPTH = 6;

// Razoring
int RAZORING_DEPTH = 3;
int RAZORING_MARGIN = 200;

// Singular Extensions
int SE_DEPTH = 7;
int SEE_TT_DEPTH_SUBTRACTOR = 3;
int DOUBLE_EXTENSION_MARGIN = 20;
int TRIPLE_EXTENSION_MARGIN = 40;

// Correction History
int CORRHIST_WEIGHT_SCALE = 256;
int CORRHIST_GRAIN = 256;
int CORRHIST_LIMIT = 1024;
int CORRHIST_SIZE = 16384;
int CORRHIST_MAX = 16384;

int PAWN_CORRECTION_HISTORY[2][16384];
int MINOR_CORRECTION_HISTORY[2][16384];
int NON_PAWN_CORRECTION_HISTORY[2][2][16384];

// Internal Iterative Reductions
int IIR_DEPTH = 8;
int IIR_TT_DEPTH_SUBTRACTOR = 3;
/*███████████████████████████████████████████████████████████████████████████████*\
██ ██
██ T U N A B L E S E A R C H P A R A M E T E R S ██
██ ██
\*███████████████████████████████████████████████████████████████████████████████*/


/*╔═══════════════════════════════╗
║ Static Exchange Evaluation ║
╚═══════════════════════════════╝*/
int SEE_PIECE_VALUES[] = {100, 300, 300, 500, 1200, 0, 0};
int QS_SEE_THRESHOLD = 0;
int SEE_MOVE_ORDERING_THRESHOLD = -82;
int SEE_QUIET_THRESHOLD = -67;
int SEE_NOISY_THRESHOLD = -32;
int SEE_DEPTH = 10;


/*╔═══════════════════════╗
║ Null Move Pruning ║
╚═══════════════════════╝*/
int NMP_DEPTH = 3;
int NMP_BASE_REDUCTION = 3;
int NMP_REDUCTION_DEPTH_DIVISOR = 3;
int NMP_EVAL_DIVISOR = 400;


/*╔═══════════════════════╗
║ Late Move Reduction ║
╚═══════════════════════╝*/
int LMR_TABLE[2][maxPly][maxPly];
double LMR_TABLE_BASE_NOISY = 0.38;
double LMR_TABLE_NOISY_DIVISOR = 3.76;
double LMR_TABLE_BASE_QUIET = 1.01;
double LMR_TABLE_QUIET_DIVISOR = 2.32;
int LMR_FULL_DEPTH_MOVES = 4;
int LMR_REDUCTION_LIMIT = 3;
int DEEPER_LMR_MARGIN = 35;
int QUIET_HISTORY_LMR_DIVISOR = 4096;
int QUIET_HISTORY_LMR_MINIMUM_SCALER = 3072;
int QUIET_HISTORY_LMR_MAXIMUM_SCALER = 3072;
int QUIET_NON_PV_LMR_SCALER = 1024;
int CUT_NODE_LMR_SCALER = 1024;
int TT_PV_LMR_SCALER = 1024;




/*╔═══════════════════════╗
║ Late Move Pruning ║
╚═══════════════════════╝*/
int LMP_BASE = 4;
int LMP_MULTIPLIER = 3;


/*╔════════════════════╗
║ Futility Pruning ║
╚════════════════════╝*/
int FUTILITY_PRUNING_OFFSET[] = {0, 82, 41, 20, 10, 5};
int FP_DEPTH = 5;
int FP_MARGIN = 82;


/*╔══════════════════════════════╗
║ Reverse Futility Pruning ║
╚══════════════════════════════╝*/
int RFP_MARGIN = 82;
int RFP_IMPROVING_MARGIN = 65;
int RFP_DEPTH = 6;


/*╔══════════╗
║ Razoring ║
╚══════════╝*/
int RAZORING_DEPTH = 3;
int RAZORING_MARGIN = 200;


/*╔═════════════════════╗
║ Singular Extensions ║
╚═════════════════════╝*/
int SE_DEPTH = 7;
int SE_TT_DEPTH_SUBTRACTOR = 3;
// Positive Extensions
int DOUBLE_EXTENSION_MARGIN = 20;
int TRIPLE_EXTENSION_MARGIN = 40;
int QUADRUPLE_EXTENSION_MARGIN = 85;
// Negative Extensions
int DOUBLE_NEGATIVE_EXTENSION_MARGIN = 60;
int TRIPLE_NEGATIVE_EXTENSION_MARGIN = 90;



/*╔════════════════════╗
║ Correction History ║
╚════════════════════╝*/
int CORRHIST_WEIGHT_SCALE = 256;
int CORRHIST_GRAIN = 256;
int CORRHIST_LIMIT = 1024;
int CORRHIST_SIZE = 16384;
int CORRHIST_MAX = 16384;

int PAWN_CORRECTION_HISTORY[2][16384];
int MINOR_CORRECTION_HISTORY[2][16384];
int NON_PAWN_CORRECTION_HISTORY[2][2][16384];


/*╔═══════════════════════════════╗
║ Internal Iterative Reductions ║
╚═══════════════════════════════╝*/
int IIR_DEPTH = 8;
int IIR_TT_DEPTH_SUBTRACTOR = 3;

/*╔══════════════════════════════╗
║ Aspiration Windows ║
╚══════════════════════════════╝*/
int ASP_WINDOW_BASE = 9;
int ASP_WINDOW_MIN_DEPTH = 4;
double ASP_WINDOW_MULTIPLIER = 1.8;


U64 searchNodes = 0;
Expand Down Expand Up @@ -111,11 +165,11 @@ void initializeLMRTable(void) {
Move ordering
=======================

1. PV move
2. Captures in MVV/LVA
3. 1st killer move
4. 2nd killer move
5. History moves
1. TT Move
2. PV Moves
2. Captures in MVV/LVA / SEE
3. 1st killer move
5. History moves / Root History / Continuation History
*/

// score moves
Expand Down Expand Up @@ -845,13 +899,13 @@ int negamax(int alpha, int beta, int depth, board* pos, time* time, bool cutNode

uint16_t rfpMargin = improving ? RFP_IMPROVING_MARGIN * (depth - 1) : RFP_MARGIN * depth;

// reverse futility pruning
// Reverse Futility Pruning
if (!pos->isSingularMove[pos->ply] &&
depth <= RFP_DEPTH && !pvNode && !in_check && (!tt_hit || ttAdjustedEval != static_eval) &&
ttAdjustedEval - rfpMargin >= beta)
return ttAdjustedEval;

// null move pruning
// Null Move Pruning
if (!pos->isSingularMove[pos->ply] && !pvNode &&
depth >= NMP_DEPTH && !in_check && !rootNode &&
static_eval >= beta &&
Expand Down Expand Up @@ -1018,7 +1072,7 @@ int negamax(int alpha, int beta, int depth, board* pos, time* time, bool cutNode

// Singular Extensions
if (!rootNode && depth >= SE_DEPTH + tt_pv && currentMove == tt_move && !pos->isSingularMove[pos->ply] &&
tt_depth >= depth - SEE_TT_DEPTH_SUBTRACTOR && tt_flag != hashFlagBeta &&
tt_depth >= depth - SE_TT_DEPTH_SUBTRACTOR && tt_flag != hashFlagBeta &&
abs(tt_score) < mateScore) {
const int singularBeta = tt_score - depth;
const int singularDepth = (depth - 1) / 2;
Expand Down Expand Up @@ -1060,9 +1114,20 @@ int negamax(int alpha, int beta, int depth, board* pos, time* time, bool cutNode
if (!getMoveCapture(currentMove) && singularScore + TRIPLE_EXTENSION_MARGIN < singularBeta) {
extensions++;
}

// Quadruple Extension
if (singularScore <= singularBeta - 85) {
// ╔═══════════════════════════╗
// ║ /\ ║
// ║ / \ ║
// ║ <SCALER> ║
// ║ \ / ║
// ║ \/ ║
// ╟ «-·´¯`·.¸¸.»·´¯`·-» ╢
// ║ Scaling STC / LTC ║
// ║ STC: 0.93 +- 1.94 ║
// ║ LTC: 14.05 +- 7.19 ║
// ╚═══════════════════════════╝

// ~~~~ Quadruple Extension ~~~~ //
if (singularScore <= singularBeta - QUADRUPLE_EXTENSION_MARGIN) {
extensions++;
}

Expand All @@ -1077,15 +1142,15 @@ int negamax(int alpha, int beta, int depth, board* pos, time* time, bool cutNode
else if (tt_score >= beta) {
extensions -= 1 + !pvNode;
// Double Negative Extension
if (!pvNode && tt_score >= beta + 60) {
if (!pvNode && tt_score >= beta + DOUBLE_NEGATIVE_EXTENSION_MARGIN) {
extensions -= 1;

// High Depth Extension
// High Depth Reduction
depth -= depth > 12;
}

// Triple Negative Extension
if (notTactical && tt_score - 90 >= beta) {
if (notTactical && tt_score - TRIPLE_NEGATIVE_EXTENSION_MARGIN >= beta) {
extensions -= 1;
}

Expand Down Expand Up @@ -1137,31 +1202,33 @@ int negamax(int alpha, int beta, int depth, board* pos, time* time, bool cutNode

int new_depth = depth - 1 + extensions;

int lmrReduction = getLmrReduction(depth, legal_moves, notTactical);
int lmrReduction = getLmrReduction(depth, legal_moves, notTactical) * 1024;

/* All Moves */

// Reduce More
if (cutNode) {
lmrReduction += 1;
lmrReduction += CUT_NODE_LMR_SCALER;
}

if (notTactical) {
// Reduce More
if (!pvNode && quietMoves >= 4) {
lmrReduction += 1;
lmrReduction += QUIET_NON_PV_LMR_SCALER;
}

// if the move have good history decrease reduction other hand the move have bad history then reduce more
int moveHistoryReduction = moveHistory / 4096;
lmrReduction -= clamp(moveHistoryReduction, -3, 3);
int moveHistoryReduction = moveHistory / QUIET_HISTORY_LMR_DIVISOR;
lmrReduction -= clamp(moveHistoryReduction * 1024, -QUIET_HISTORY_LMR_MINIMUM_SCALER, QUIET_HISTORY_LMR_MINIMUM_SCALER);
}

// Reduce Less
if (tt_pv) {
lmrReduction -= 1;
lmrReduction -= TT_PV_LMR_SCALER;
}

lmrReduction /= 1024;



int reduced_depth = myMAX(1, myMIN(new_depth - lmrReduction, new_depth));
Expand Down Expand Up @@ -1337,7 +1404,7 @@ void searchPosition(int depth, board* position, bool benchmark, time* time) {
time->stopped = 1;
}

int window = 9;
int window = ASP_WINDOW_BASE;
int aspirationWindowDepth = current_depth;

while (true) {
Expand All @@ -1350,7 +1417,7 @@ void searchPosition(int depth, board* position, bool benchmark, time* time) {
break;
}

if (current_depth >= 4) {
if (current_depth >= ASP_WINDOW_MIN_DEPTH) {
alpha = myMAX(-infinity, score - window);
beta = myMIN(infinity, score + window);
}
Expand Down