From 714e857c246879a513cdf0d3d3fe757a42d7030a Mon Sep 17 00:00:00 2001 From: protonspring Date: Sun, 3 Mar 2019 07:53:36 -0700 Subject: [PATCH] Shrink Reductions[] array to one dimension This is a non-functional patch which shrinks the reductions array. This saves about 8Kb of memory. The only slow part of master's reductions array is the calculation of the log values, so using a separate array for those values and calculating the rest real-time appears to be just as fast as master. STC LLR: 2.96 (-2.94,2.94) [-3.00,1.00] Total: 63245 W: 13906 L: 13866 D: 35473 http://tests.stockfishchess.org/tests/view/5c7b571f0ebc5925cffdc104 No funcional change. --- src/search.cpp | 19 +++++-------------- 1 file changed, 5 insertions(+), 14 deletions(-) diff --git a/src/search.cpp b/src/search.cpp index 23402939..39875cb4 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -73,10 +73,11 @@ namespace { // Futility and reductions lookup tables, initialized at startup int FutilityMoveCounts[2][16]; // [improving][depth] - int Reductions[2][64][64]; // [improving][depth][moveNumber] + int Reductions[64]; // [depth or moveNumber] template Depth reduction(bool i, Depth d, int mn) { - return (Reductions[i][std::min(d / ONE_PLY, 63)][std::min(mn, 63)] - PvNode) * ONE_PLY; + int r = Reductions[std::min(d / ONE_PLY, 63)] * Reductions[std::min(mn, 63)] / 1024; + return ((r + 512) / 1024 + (!i && r > 1024) - PvNode) * ONE_PLY; } // History and stats update bonus, based on depth @@ -156,18 +157,8 @@ namespace { void Search::init() { - for (int imp = 0; imp <= 1; ++imp) - for (int d = 1; d < 64; ++d) - for (int mc = 1; mc < 64; ++mc) - { - double r = log(d) * log(mc) / 1.95; - - Reductions[imp][d][mc] = std::round(r); - - // Increase reduction for non-PV nodes when eval is not improving - if (!imp && r > 1.0) - Reductions[imp][d][mc]++; - } + for (int i = 1; i < 64; ++i) + Reductions[i] = int(1024 * std::log(i) / std::sqrt(1.95)); for (int d = 0; d < 16; ++d) { -- 2.39.2