diff --git a/src/search.cpp b/src/search.cpp index ac6b8608..73fc8a55 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -591,13 +591,13 @@ namespace { bool captureOrPromotion, doFullDepthSearch, moveCountPruning, ttCapture, singularQuietLMR, noLMRExtension; Piece movedPiece; - int moveCount, captureCount, quietCount; + int moveCount, captureCount, quietCount, bestMoveCount; // Step 1. Initialize node ss->inCheck = pos.checkers(); priorCapture = pos.captured_piece(); Color us = pos.side_to_move(); - moveCount = captureCount = quietCount = ss->moveCount = 0; + moveCount = bestMoveCount = captureCount = quietCount = ss->moveCount = 0; bestValue = -VALUE_INFINITE; maxValue = VALUE_INFINITE; @@ -1186,8 +1186,9 @@ moves_loop: // When in check, search starts here { Depth r = reduction(improving, depth, moveCount, rangeReduction > 2); - // Decrease reduction if on the PV (~1 Elo) - if (PvNode) + // Decrease reduction if on the PV (~2 Elo) + if ( PvNode + && bestMoveCount <= 3) r--; // Decrease reduction if the ttHit running average is large (~0 Elo) @@ -1340,7 +1341,10 @@ moves_loop: // When in check, search starts here update_pv(ss->pv, move, (ss+1)->pv); if (PvNode && value < beta) // Update alpha! Always alpha < beta + { alpha = value; + bestMoveCount++; + } else { assert(value >= beta); // Fail high