From: Marco Costalba Date: Sun, 28 Mar 2010 11:04:41 +0000 (+0100) Subject: Revert LMR reduction based on thinking time X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=2a14123550eb6ebce6be3a0c4d3938e533e748b2;ds=sidebyside Revert LMR reduction based on thinking time After 500 games at 5+0 on my QUAD (3 days) there is no difference with old version, so probably it is a feature that doesn't scale with search depth. So revert for now, perhaps we should readd under a different form. Signed-off-by: Marco Costalba --- diff --git a/src/search.cpp b/src/search.cpp index 692754b1..882fee6f 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -215,14 +215,12 @@ namespace { // Step 14. Reduced search - int ReductionLevel; // 0 = most aggressive reductions, 7 = minimum reductions - // Reduction lookup tables (initialized at startup) and their getter functions - int8_t PVReductionMatrix[8][64][64]; // [depth][moveNumber] - int8_t NonPVReductionMatrix[8][64][64]; // [depth][moveNumber] + int8_t PVReductionMatrix[64][64]; // [depth][moveNumber] + int8_t NonPVReductionMatrix[64][64]; // [depth][moveNumber] - inline Depth pv_reduction(Depth d, int mn) { return (Depth) PVReductionMatrix[ReductionLevel][Min(d / 2, 63)][Min(mn, 63)]; } - inline Depth nonpv_reduction(Depth d, int mn) { return (Depth) NonPVReductionMatrix[ReductionLevel][Min(d / 2, 63)][Min(mn, 63)]; } + inline Depth pv_reduction(Depth d, int mn) { return (Depth) PVReductionMatrix[Min(d / 2, 63)][Min(mn, 63)]; } + inline Depth nonpv_reduction(Depth d, int mn) { return (Depth) NonPVReductionMatrix[Min(d / 2, 63)][Min(mn, 63)]; } // Common adjustments @@ -546,30 +544,20 @@ bool think(const Position& pos, bool infinite, bool ponder, int side_to_move, return !Quit; } -// init_reduction_tables() is called by init_search() and initializes -// the tables used by LMR. -static void init_reduction_tables(int8_t pvTable[64][64], int8_t nonPvTable[64][64], int pvInhib, int nonPvInhib) -{ - double pvBase = 1.001 - log(3.0) * log(16.0) / pvInhib; - double nonPvBase = 1.001 - log(3.0) * log(4.0) / nonPvInhib; +/// init_search() is called during startup. It initializes various lookup tables + +void init_search() { + + // Init our reduction lookup tables for (int i = 1; i < 64; i++) // i == depth (OnePly = 1) for (int j = 1; j < 64; j++) // j == moveNumber { - double pvRed = pvBase + log(double(i)) * log(double(j)) / pvInhib; - double nonPVRed = nonPvBase + log(double(i)) * log(double(j)) / nonPvInhib; - - pvTable[i][j] = (int8_t) ( pvRed >= 1.0 ? floor( pvRed * int(OnePly)) : 0); - nonPvTable[i][j] = (int8_t) (nonPVRed >= 1.0 ? floor(nonPVRed * int(OnePly)) : 0); + double pvRed = 0.5 + log(double(i)) * log(double(j)) / 6.0; + double nonPVRed = 0.5 + log(double(i)) * log(double(j)) / 3.0; + PVReductionMatrix[i][j] = (int8_t) ( pvRed >= 1.0 ? floor( pvRed * int(OnePly)) : 0); + NonPVReductionMatrix[i][j] = (int8_t) (nonPVRed >= 1.0 ? floor(nonPVRed * int(OnePly)) : 0); } -} - -// init_search() is called during startup. It initializes various lookup tables -void init_search() { - - // Init reduction lookup tables - for (int i = 0; i < 8; i++) - init_reduction_tables(PVReductionMatrix[i], NonPVReductionMatrix[i], int(4 * pow(1.3, i)), int(2 * pow(1.3, i))); // Init futility margins array for (int i = 0; i < 16; i++) // i == depth (OnePly = 2) @@ -672,19 +660,6 @@ namespace { beta = Min(ValueByIteration[Iteration - 1] + AspirationDelta, VALUE_INFINITE); } - // Choose optimum reduction level - ReductionLevel = 2; - - if (UseTimeManagement) - { - int level = int(floor(log(float(MaxSearchTime) / current_search_time()) / log(2.0) + 1.0)); - ReductionLevel = Min(Max(level, 0), 7); - } - else - { - //FIXME - } - // Search to the current depth, rml is updated and sorted, alpha and beta could change value = root_search(p, ss, rml, &alpha, &beta);