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Small cleanup and in evaluate_passed_pawns()

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No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba 2009-10-11 11:12:53 +02:00
parent d6b04c2798
commit ab4d26f9bd
1 changed files with 21 additions and 22 deletions
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43
src/evaluate.cpp
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@ -892,7 +892,7 @@ namespace {
// evaluate_passed_pawns() evaluates the passed pawns of the given color // evaluate_passed_pawns() evaluates the passed pawns of the given color
template<Color Us> template<Color Us>
void evaluate_passed_pawns_of_color(const Position& pos, bool hasUnstoppable[], int movesToGo[], EvalInfo& ei) { void evaluate_passed_pawns_of_color(const Position& pos, int movesToGo[], EvalInfo& ei) {
const Color Them = (Us == WHITE ? BLACK : WHITE); const Color Them = (Us == WHITE ? BLACK : WHITE);
@ -910,15 +910,16 @@ namespace {
int r = int(relative_rank(Us, s) - RANK_2); int r = int(relative_rank(Us, s) - RANK_2);
int tr = Max(0, r * (r - 1)); int tr = Max(0, r * (r - 1));
Square blockSq = s + pawn_push(Us);
// Base bonus based on rank // Base bonus based on rank
Value mbonus = Value(20 * tr); Value mbonus = Value(20 * tr);
Value ebonus = Value(10 + r * r * 10); Value ebonus = Value(10 + r * r * 10);
// Adjust bonus based on king proximity // Adjust bonus based on king proximity
if (tr != 0) if (tr)
{ {
Square blockSq = s + pawn_push(Us);
ebonus -= Value(square_distance(ourKingSq, blockSq) * 3 * tr); ebonus -= Value(square_distance(ourKingSq, blockSq) * 3 * tr);
ebonus -= Value(square_distance(ourKingSq, blockSq + pawn_push(Us)) * 1 * tr); ebonus -= Value(square_distance(ourKingSq, blockSq + pawn_push(Us)) * 1 * tr);
ebonus += Value(square_distance(theirKingSq, blockSq) * 6 * tr); ebonus += Value(square_distance(theirKingSq, blockSq) * 6 * tr);
@ -926,29 +927,31 @@ namespace {
// If the pawn is free to advance, increase bonus // If the pawn is free to advance, increase bonus
if (pos.square_is_empty(blockSq)) if (pos.square_is_empty(blockSq))
{ {
// There are no enemy pawns in the pawn's path
b2 = squares_in_front_of(Us, s); b2 = squares_in_front_of(Us, s);
b3 = b2 & ei.attacked_by(Them);
assert((b2 & pos.pieces(PAWN, Them)) == EmptyBoardBB);
// Squares attacked by us
b4 = b2 & ei.attacked_by(Us); b4 = b2 & ei.attacked_by(Us);
// Squares attacked or occupied by enemy pieces
b3 = b2 & (ei.attacked_by(Them) | pos.pieces_of_color(Them));
// If there is an enemy rook or queen attacking the pawn from behind, // If there is an enemy rook or queen attacking the pawn from behind,
// add all X-ray attacks by the rook or queen. // add all X-ray attacks by the rook or queen.
if ( bit_is_set(ei.attacked_by(Them, ROOK) | ei.attacked_by(Them, QUEEN), s) if ( bit_is_set(ei.attacked_by(Them, ROOK) | ei.attacked_by(Them, QUEEN), s)
&& (squares_behind(Us, s) & pos.pieces(ROOK, QUEEN, Them))) && (squares_behind(Us, s) & pos.pieces(ROOK, QUEEN, Them)))
b3 = b2; b3 = b2;
// Squares attacked or occupied by enemy pieces
b3 |= (b2 & pos.pieces_of_color(Them));
// There are no enemy pawns in the pawn's path
assert((b2 & pos.pieces(PAWN, Them)) == EmptyBoardBB);
// Are any of the squares in the pawn's path attacked or occupied by the enemy? // Are any of the squares in the pawn's path attacked or occupied by the enemy?
if (b3 == EmptyBoardBB) if (b3 == EmptyBoardBB)
// No enemy attacks or pieces, huge bonus! // No enemy attacks or pieces, huge bonus!
// Even bigger if we protect the pawn's path
ebonus += Value(tr * (b2 == b4 ? 17 : 15)); ebonus += Value(tr * (b2 == b4 ? 17 : 15));
else else
// OK, there are enemy attacks or pieces (but not pawns). Are those // OK, there are enemy attacks or pieces (but not pawns). Are those
// squares which are attacked by the enemy also attacked by us? // squares which are attacked by the enemy also attacked by us ?
// If yes, big bonus (but smaller than when there are no enemy attacks), // If yes, big bonus (but smaller than when there are no enemy attacks),
// if no, somewhat smaller bonus. // if no, somewhat smaller bonus.
ebonus += Value(tr * ((b3 & b4) == b3 ? 13 : 8)); ebonus += Value(tr * ((b3 & b4) == b3 ? 13 : 8));
@ -986,10 +989,7 @@ namespace {
mtg += blockerCount; mtg += blockerCount;
d += blockerCount; d += blockerCount;
if (d < 0) if (d < 0)
{ movesToGo[Us] = movesToGo[Us] ? Min(movesToGo[Us], mtg) : mtg;
hasUnstoppable[Us] = true;
movesToGo[Us] = Min(movesToGo[Us], mtg);
}
} }
} }
@ -1020,19 +1020,18 @@ namespace {
void evaluate_passed_pawns(const Position& pos, EvalInfo& ei) { void evaluate_passed_pawns(const Position& pos, EvalInfo& ei) {
bool hasUnstoppable[2] = {false, false}; int movesToGo[2] = {0, 0};
int movesToGo[2] = {100, 100};
// Evaluate pawns for each color // Evaluate pawns for each color
evaluate_passed_pawns_of_color<WHITE>(pos, hasUnstoppable, movesToGo, ei); evaluate_passed_pawns_of_color<WHITE>(pos, movesToGo, ei);
evaluate_passed_pawns_of_color<BLACK>(pos, hasUnstoppable, movesToGo, ei); evaluate_passed_pawns_of_color<BLACK>(pos, movesToGo, ei);
// Does either side have an unstoppable passed pawn? // Does either side have an unstoppable passed pawn?
if (hasUnstoppable[WHITE] && !hasUnstoppable[BLACK]) if (movesToGo[WHITE] && !movesToGo[BLACK])
ei.egValue += UnstoppablePawnValue - Value(0x40 * movesToGo[WHITE]); ei.egValue += UnstoppablePawnValue - Value(0x40 * movesToGo[WHITE]);
else if (hasUnstoppable[BLACK] && !hasUnstoppable[WHITE]) else if (movesToGo[BLACK] && !movesToGo[WHITE])
ei.egValue -= UnstoppablePawnValue - Value(0x40 * movesToGo[BLACK]); ei.egValue -= UnstoppablePawnValue - Value(0x40 * movesToGo[BLACK]);
else if (hasUnstoppable[BLACK] && hasUnstoppable[WHITE]) else if (movesToGo[BLACK] && movesToGo[WHITE])
{ {
// Both sides have unstoppable pawns! Try to find out who queens // Both sides have unstoppable pawns! Try to find out who queens
// first. We begin by transforming 'movesToGo' to the number of // first. We begin by transforming 'movesToGo' to the number of