diff --git a/src/search.cpp b/src/search.cpp index edeed9c0..f3a96ae2 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -1165,6 +1165,8 @@ moves_loop: // When in check, search starts here // Step 15. Make the move pos.do_move(move, st, givesCheck); + bool doDeeperSearch = false; + // Step 16. Late moves reduction / extension (LMR, ~200 Elo) // We use various heuristics for the sons of a node after the first son has // been searched. In general we would like to reduce them, but there are many @@ -1237,6 +1239,7 @@ moves_loop: // When in check, search starts here // If the son is reduced and fails high it will be re-searched at full depth doFullDepthSearch = value > alpha && d < newDepth; + doDeeperSearch = value > alpha + 88; didLMR = true; } else @@ -1248,7 +1251,7 @@ moves_loop: // When in check, search starts here // Step 17. Full depth search when LMR is skipped or fails high if (doFullDepthSearch) { - value = -search(pos, ss+1, -(alpha+1), -alpha, newDepth, !cutNode); + value = -search(pos, ss+1, -(alpha+1), -alpha, newDepth + doDeeperSearch, !cutNode); // If the move passed LMR update its stats if (didLMR && !captureOrPromotion)