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Simplify out the eval-based NMP R adjustment #260

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Merged
kevlu8 merged 1 commit into from
Feb 2, 2026
Merged

Simplify out the eval-based NMP R adjustment #260

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2 changes: 1 addition & 1 deletion engine/search.cpp
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Expand Up @@ -472,7 +472,7 @@ Value negamax(ThreadInfo &ti, int depth, Value alpha = -VALUE_INFINITE, Value be
ti.line[ply].corr_hist = &ti.thread_hist.corrhist_cont[board.side][0][0];
board.make_move(NullMove);
// Perform a reduced-depth search
Value r = NMP_R_VALUE + depth / 4 + std::min(3, (tt_corr_eval - beta) / 400);
Value r = NMP_R_VALUE + depth / 3;
Value null_score = -negamax(ti, depth - r, -beta, -beta + 1, -side, 0, !cutnode, ply+1);
board.unmake_move();
ti.line[ply].cont_hist = nullptr;
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2 changes: 1 addition & 1 deletion engine/search.hpp
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Expand Up @@ -33,7 +33,7 @@
// Null-move pruning reduction value
// This is the amount of depth we reduce the search by
// when we do a null-move search
#define NMP_R_VALUE 6
#define NMP_R_VALUE 7

// Delta pruning threshold
#define DELTA_THRESHOLD 355
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