From 0143c6f0c2137aac0ea3531d0f1d95009be0924c Mon Sep 17 00:00:00 2001 From: Joost VandeVondele Date: Wed, 18 Apr 2018 19:17:16 +0200 Subject: [PATCH] Document Elo impact of the LMR part of search Similar to before, document Elo impact of various LMR steps Tests run by @jerrydonaldwatson t1 http://tests.stockfishchess.org/tests/view/5abece950ebc591a560aad0b t2 http://tests.stockfishchess.org/tests/view/5abecf0c0ebc591a560aad0d t3 http://tests.stockfishchess.org/tests/view/5abecf7b0ebc591a560aad0f t4 http://tests.stockfishchess.org/tests/view/5abecfe70ebc591a560aad14 t5 http://tests.stockfishchess.org/tests/view/5abed42b0ebc591a560aad33 t6 http://tests.stockfishchess.org/tests/view/5abed0b90ebc591a560aad19 t7 http://tests.stockfishchess.org/tests/view/5abed1240ebc591a560aad1b t8 http://tests.stockfishchess.org/tests/view/5abed1b90ebc591a560aad1d No functional change. --- src/search.cpp | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/src/search.cpp b/src/search.cpp index 25383aae..b61a21ad 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -978,29 +978,29 @@ moves_loop: // When in check, search starts from here { Depth r = reduction(improving, depth, moveCount); - if (captureOrPromotion) + if (captureOrPromotion) // (~5 Elo) r -= r ? ONE_PLY : DEPTH_ZERO; else { - // Decrease reduction if opponent's move count is high + // Decrease reduction if opponent's move count is high (~5 Elo) if ((ss-1)->moveCount > 15) r -= ONE_PLY; - // Decrease reduction for exact PV nodes + // Decrease reduction for exact PV nodes (~0 Elo) if (pvExact) r -= ONE_PLY; - // Increase reduction if ttMove is a capture + // Increase reduction if ttMove is a capture (~0 Elo) if (ttCapture) r += ONE_PLY; - // Increase reduction for cut nodes + // Increase reduction for cut nodes (~5 Elo) if (cutNode) r += 2 * ONE_PLY; // Decrease reduction for moves that escape a capture. Filter out // castling moves, because they are coded as "king captures rook" and - // hence break make_move(). + // hence break make_move(). (~5 Elo) else if ( type_of(move) == NORMAL && !pos.see_ge(make_move(to_sq(move), from_sq(move)))) r -= 2 * ONE_PLY; @@ -1011,14 +1011,14 @@ moves_loop: // When in check, search starts from here + (*contHist[3])[movedPiece][to_sq(move)] - 4000; - // Decrease/increase reduction by comparing opponent's stat score + // Decrease/increase reduction by comparing opponent's stat score (~10 Elo) if (ss->statScore >= 0 && (ss-1)->statScore < 0) r -= ONE_PLY; else if ((ss-1)->statScore >= 0 && ss->statScore < 0) r += ONE_PLY; - // Decrease/increase reduction for moves with a good/bad history + // Decrease/increase reduction for moves with a good/bad history (~30 Elo) r = std::max(DEPTH_ZERO, (r / ONE_PLY - ss->statScore / 20000) * ONE_PLY); } -- 2.39.2