diff --git a/src/search.cpp b/src/search.cpp index af8ddaba..c48b74bc 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -779,8 +779,10 @@ namespace { ? ss->staticEval > (ss-4)->staticEval || (ss-4)->staticEval == VALUE_NONE : ss->staticEval > (ss-2)->staticEval; - // Step 7. Futility pruning: child node (~50 Elo) + // Step 7. Futility pruning: child node (~50 Elo). + // The depth condition is important for mate finding. if ( !PvNode + && depth < 9 && eval - futility_margin(depth, improving) >= beta && eval < VALUE_KNOWN_WIN) // Do not return unproven wins return eval; @@ -989,7 +991,7 @@ moves_loop: // When in check, search starts here // Calculate new depth for this move newDepth = depth - 1; - // Step 13. Pruning at shallow depth (~200 Elo) + // Step 13. Pruning at shallow depth (~200 Elo). Depth conditions are important for mate finding. if ( !rootNode && pos.non_pawn_material(us) && bestValue > VALUE_TB_LOSS_IN_MAX_PLY) @@ -1023,6 +1025,7 @@ moves_loop: // When in check, search starts here // Futility pruning: parent node (~5 Elo) if ( !ss->inCheck + && lmrDepth < 7 && ss->staticEval + 174 + 157 * lmrDepth <= alpha) continue;