diff --git a/src/evaluate.cpp b/src/evaluate.cpp index 4c10a199..c98a83fc 100644 --- a/src/evaluate.cpp +++ b/src/evaluate.cpp @@ -794,9 +794,8 @@ namespace { Color strongSide = eg > VALUE_DRAW ? WHITE : BLACK; int sf = me->scale_factor(pos, strongSide); - // If we don't already have an unusual scale factor, check for certain - // types of endgames, and use a lower scale for those. - if (sf == SCALE_FACTOR_NORMAL || sf == SCALE_FACTOR_ONEPAWN) + // If scale is not already specific, scale down the endgame via general heuristics + if (sf == SCALE_FACTOR_NORMAL) { if (pos.opposite_bishops()) { @@ -810,12 +809,8 @@ namespace { else sf = 46; } - // Endings where weaker side can place his king in front of the enemy's - // pawns are drawish. - else if ( abs(eg) <= BishopValueEg - && pos.count(strongSide) <= 2 - && !pos.pawn_passed(~strongSide, pos.square(~strongSide))) - sf = 37 + 7 * pos.count(strongSide); + else + sf = std::min(40 + 7 * pos.count(strongSide), sf); } return ScaleFactor(sf); diff --git a/src/material.cpp b/src/material.cpp index 921e3007..b18d29d0 100644 --- a/src/material.cpp +++ b/src/material.cpp @@ -206,12 +206,6 @@ Entry* probe(const Position& pos) { e->factor[BLACK] = uint8_t(npm_b < RookValueMg ? SCALE_FACTOR_DRAW : npm_w <= BishopValueMg ? 4 : 14); - if (pos.count(WHITE) == 1 && npm_w - npm_b <= BishopValueMg) - e->factor[WHITE] = (uint8_t) SCALE_FACTOR_ONEPAWN; - - if (pos.count(BLACK) == 1 && npm_b - npm_w <= BishopValueMg) - e->factor[BLACK] = (uint8_t) SCALE_FACTOR_ONEPAWN; - // Evaluate the material imbalance. We use PIECE_TYPE_NONE as a place holder // for the bishop pair "extended piece", which allows us to be more flexible // in defining bishop pair bonuses. diff --git a/src/types.h b/src/types.h index 72c5699f..ab5e1b88 100644 --- a/src/types.h +++ b/src/types.h @@ -159,7 +159,6 @@ enum Phase { enum ScaleFactor { SCALE_FACTOR_DRAW = 0, - SCALE_FACTOR_ONEPAWN = 48, SCALE_FACTOR_NORMAL = 64, SCALE_FACTOR_MAX = 128, SCALE_FACTOR_NONE = 255