From e90341f9c9cd24e75aba2485b2ab1e445f4a5b70 Mon Sep 17 00:00:00 2001 From: Stefan Geschwentner Date: Tue, 4 Oct 2022 18:16:20 +0200 Subject: [PATCH] Tweak history initialization Simplify initialization of continuation history by using everywhere the same starting value. STC: LLR: 2.94 (-2.94,2.94) <-1.75,0.25> Total: 90952 W: 24312 L: 24153 D: 42487 Ptnml(0-2): 356, 10168, 24290, 10285, 377 https://tests.stockfishchess.org/tests/view/633948f235f43d649ff61fd0 LTC: LLR: 2.96 (-2.94,2.94) <-1.75,0.25> Total: 162416 W: 43540 L: 43466 D: 75410 Ptnml(0-2): 77, 16289, 48417, 16333, 92 https://tests.stockfishchess.org/tests/view/6339ee8a35f43d649ff63986 closes https://github.com/official-stockfish/Stockfish/pull/4186 Bench: 4156027 --- src/search.cpp | 4 ++-- src/search.h | 3 --- src/thread.cpp | 7 ++----- 3 files changed, 4 insertions(+), 10 deletions(-) diff --git a/src/search.cpp b/src/search.cpp index 7019635d..3c2ae3e5 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -1549,8 +1549,8 @@ moves_loop: // When in check, search starts here // Continuation history based pruning (~2 Elo) if ( !capture && bestValue > VALUE_TB_LOSS_IN_MAX_PLY - && (*contHist[0])[pos.moved_piece(move)][to_sq(move)] < CounterMovePruneThreshold - && (*contHist[1])[pos.moved_piece(move)][to_sq(move)] < CounterMovePruneThreshold) + && (*contHist[0])[pos.moved_piece(move)][to_sq(move)] < 0 + && (*contHist[1])[pos.moved_piece(move)][to_sq(move)] < 0) continue; // movecount pruning for quiet check evasions diff --git a/src/search.h b/src/search.h index 4ad5784f..f264bcae 100644 --- a/src/search.h +++ b/src/search.h @@ -31,9 +31,6 @@ class Position; namespace Search { -/// Threshold used for countermoves based pruning -constexpr int CounterMovePruneThreshold = 0; - /// Stack struct keeps track of the information we need to remember from nodes /// shallower and deeper in the tree during the search. Each search thread has diff --git a/src/thread.cpp b/src/thread.cpp index 288588b0..9ce408e0 100644 --- a/src/thread.cpp +++ b/src/thread.cpp @@ -64,12 +64,9 @@ void Thread::clear() { for (bool inCheck : { false, true }) for (StatsType c : { NoCaptures, Captures }) - { for (auto& to : continuationHistory[inCheck][c]) - for (auto& h : to) - h->fill(-71); - continuationHistory[inCheck][c][NO_PIECE][0]->fill(Search::CounterMovePruneThreshold - 1); - } + for (auto& h : to) + h->fill(-71); } -- 2.39.2