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Remove conditional_more_than_two().

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This is a functional simplification that removes the conditional_more_than_two()
function, which was quite strange and kooky. Note the very minor change to the bench
value.

See this thread for relevant comments on the passing branch:
protonspring/Stockfish@d89730d...ff35b50

STC
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 59760 W: 11411 L: 11311 D: 37038
Ptnml(0-2): 992, 6863, 14044, 7015, 966
https://tests.stockfishchess.org/tests/view/5f179988c09435d870cb9b9a

LTC
LLR: 2.93 (-2.94,2.94) {-1.50,0.50}
Total: 45208 W: 5553 L: 5497 D: 34158
Ptnml(0-2): 315, 4081, 13761, 4127, 320
https://tests.stockfishchess.org/tests/view/5f184847c09435d870cb9bee

closes https://github.com/official-stockfish/Stockfish/pull/2826

Bench: 4578290
This commit is contained in:
protonspring 2020-07-25 07:32:19 -06:00 • committed by Stéphane Nicolet
parent d89730d5c8
commit f0abde241d
2 changed files with 7 additions and 11 deletions
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6
src/bitboard.h
View file

@ -130,12 +130,6 @@ constexpr bool more_than_one(Bitboard b) {
return b & (b - 1);
}
/// Counts the occupation of the bitboard depending on the occupation of SQ_A1
/// as in `b & (1ULL << SQ_A1) ? more_than_two(b) : more_than_one(b)`
constexpr bool conditional_more_than_two(Bitboard b) {
return b & (b - 1) & (b - 2);
}
constexpr bool opposite_colors(Square s1, Square s2) {
return (s1 + rank_of(s1) + s2 + rank_of(s2)) & 1;

12
src/evaluate.cpp
View file

@ -310,13 +310,15 @@ namespace {
if (Pt == BISHOP || Pt == KNIGHT)
{
// Bonus if piece is on an outpost square or can reach one
// Bonus if the piece is on an outpost square or can reach one
// Reduced bonus for knights (BadOutpost) if few relevant targets
bb = OutpostRanks & attackedBy[Us][PAWN] & ~pe->pawn_attacks_span(Them);
Bitboard targets = pos.pieces(Them) & ~pos.pieces(PAWN);
if ( Pt == KNIGHT
&& bb & s & ~CenterFiles
&& !(b & pos.pieces(Them) & ~pos.pieces(PAWN))
&& !conditional_more_than_two(
pos.pieces(Them) & ~pos.pieces(PAWN) & (s & QueenSide ? QueenSide : KingSide)))
&& bb & s & ~CenterFiles // on a side outpost
&& !(b & targets) // no relevant attacks
&& (!more_than_one(targets & (s & QueenSide ? QueenSide : KingSide))))
score += BadOutpost;
else if (bb & s)
score += Outpost[Pt == BISHOP];