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Nmp only pawn, STC pass! #142

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Merged
ProgramciDusunur merged 2 commits into from
Dec 25, 2024
Merged

Nmp only pawn, STC pass! #142

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b4a1e00
if we only have pawns, let's stop doing NMP
ProgramciDusunur Dec 25, 2024
748a8b3
bench: 8699257
ProgramciDusunur Dec 25, 2024
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13 changes: 11 additions & 2 deletions src/search.c
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Original file line number Diff line number Diff line change
Expand Up @@ -283,6 +283,14 @@ void clearCounterMoves(void) {
}
}

uint8_t justPawns(board *pos) {
return !((pos->bitboards[N] | pos->bitboards[n] | pos->bitboards[B] |
pos->bitboards[b] | pos->bitboards[R] | pos->bitboards[r] |
pos->bitboards[Q] | pos->bitboards[q]) &
pos->occupancies[pos->side]);
}


// quiescence search
int quiescence(int alpha, int beta, board* position, time* time) {
if ((searchNodes & 2047) == 0) {
Expand Down Expand Up @@ -524,13 +532,14 @@ int negamax(int alpha, int beta, int depth, board* position, time* time, bool cu

int canPrune = in_check == 0 && pvNode == 0;


// reverse futility pruning
if (depth <= 2 && !pvNode && !in_check && static_eval - 82 * depth >= beta)
return static_eval;

// null move pruning
if (depth >= nullMoveDepth && in_check == 0 && position->ply && static_eval >= beta) {
if (depth >= nullMoveDepth &&
!in_check && position->ply && static_eval >= beta &&
!justPawns(position)) {
struct copyposition copyPosition;
// preserve board state
copyBoard(position, &copyPosition);
Expand Down
3 changes: 3 additions & 0 deletions src/search.h
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Original file line number Diff line number Diff line change
Expand Up @@ -7,6 +7,8 @@

#pragma once


#include <stdint.h>
#include "structs.h"
#include "time.h"
#include "values.h"
Expand Down Expand Up @@ -37,6 +39,7 @@ void quiescence_sort_moves(moves *moveList, board* position);
void enable_pv_scoring(moves *moveList, board* position);
void printMove(int move);
int getLmrReduction(int depth, int moveNumber);
uint8_t justPawns(board *pos);
void clearCounterMoves(void);
int quiescence(int alpha, int beta, board* position, time* time);
int negamax(int alpha, int beta, int depth, board* position, time* time, bool cutNode);
Expand Down