X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fpawns.cpp;h=b9d112f08c5e95772f0bf70437801df48a4daa5e;hp=a09fe68337d8aa7ab3bbbd5f93dc86023e901fc1;hb=a9e55d43262d11a916bdfa68cd1de0174d884cd3;hpb=ab29d8df678adb97e2bc40b04f13e4f17577ada0
diff --git a/src/pawns.cpp b/src/pawns.cpp
index a09fe683..b9d112f0 100644
--- a/src/pawns.cpp
+++ b/src/pawns.cpp
@@ -7,12 +7,12 @@
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
-
+
Stockfish is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
-
+
You should have received a copy of the GNU General Public License
along with this program. If not, see .
*/
@@ -26,6 +26,7 @@
#include
#include "pawns.h"
+#include "position.h"
////
@@ -72,13 +73,13 @@ namespace {
Value(32), Value(32), Value(32), Value(28)
};
- // Pawn chain membership bonus by file, middle game.
+ // Pawn chain membership bonus by file, middle game.
const Value ChainMidgameBonus[8] = {
Value(14), Value(16), Value(17), Value(18),
Value(18), Value(17), Value(16), Value(14)
};
- // Pawn chain membership bonus by file, endgame.
+ // Pawn chain membership bonus by file, endgame.
const Value ChainEndgameBonus[8] = {
Value(16), Value(16), Value(16), Value(16),
Value(16), Value(16), Value(16), Value(16)
@@ -96,9 +97,6 @@ namespace {
Value(80), Value(180), Value(0), Value( 0)
};
- // Evaluate pawn storms?
- const bool EvaluatePawnStorms = true;
-
// Pawn storm tables for positions with opposite castling:
const int QStormTable[64] = {
0, 0, 0, 0, 0, 0, 0, 0,
@@ -110,7 +108,7 @@ namespace {
31, 40, 40, 31, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0
};
-
+
const int KStormTable[64] = {
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0,-4,-13,-22,-27,-27,
@@ -122,14 +120,12 @@ namespace {
0, 0, 0, 0, 0, 0, 0, 0
};
- // Pawn storm open file bonuses by file:
- const int KStormOpenFileBonus[8] = {
- 45, 45, 30, 0, 0, 0, 0, 0
- };
+ // Pawn storm open file bonuses by file
+ const int KStormOpenFileBonus[8] = { 45, 45, 30, 0, 0, 0, 0, 0 };
+ const int QStormOpenFileBonus[8] = { 0, 0, 0, 0, 0, 30, 45, 30 };
- const int QStormOpenFileBonus[8] = {
- 0, 0, 0, 0, 0, 30, 45, 30
- };
+ // Pawn storm lever bonuses by file
+ const int StormLeverBonus[8] = { 20, 20, 10, 0, 0, 10, 20, 20 };
}
@@ -170,7 +166,7 @@ void PawnInfoTable::clear() {
/// PawnInfoTable::get_pawn_info() takes a position object as input, computes
-/// a PawnInfo object, and returns a pointer to it. The result is also
+/// a PawnInfo object, and returns a pointer to it. The result is also
/// stored in a hash table, so we don't have to recompute everything when
/// the same pawn structure occurs again.
@@ -182,7 +178,7 @@ PawnInfo *PawnInfoTable::get_pawn_info(const Position &pos) {
int index = int(key & (size - 1));
PawnInfo *pi = entries + index;
- // If pi->key matches the position's pawn hash key, it means that we
+ // If pi->key matches the position's pawn hash key, it means that we
// have analysed this pawn structure before, and we can simply return the
// information we found the last time instead of recomputing it
if (pi->key == key)
@@ -202,15 +198,15 @@ PawnInfo *PawnInfoTable::get_pawn_info(const Position &pos) {
Bitboard ourPawns = pos.pawns(us);
Bitboard theirPawns = pos.pawns(them);
Bitboard pawns = ourPawns;
+ int bonus;
// Initialize pawn storm scores by giving bonuses for open files
- if (EvaluatePawnStorms)
- for(File f = FILE_A; f <= FILE_H; f++)
- if(pos.file_is_half_open(us, f))
- {
- pi->ksStormValue[us] += KStormOpenFileBonus[f];
- pi->qsStormValue[us] += QStormOpenFileBonus[f];
- }
+ for (File f = FILE_A; f <= FILE_H; f++)
+ if (pos.file_is_half_open(us, f))
+ {
+ pi->ksStormValue[us] += KStormOpenFileBonus[f];
+ pi->qsStormValue[us] += QStormOpenFileBonus[f];
+ }
// Loop through all pawns of the current color and score each pawn
while (pawns)
@@ -220,7 +216,7 @@ PawnInfo *PawnInfoTable::get_pawn_info(const Position &pos) {
File f = square_file(s);
Rank r = square_rank(s);
- assert(pos.piece_on(s) == pawn_of_color(us));
+ assert(pos.piece_on(s) == piece_of_color_and_type(us, PAWN));
// The file containing the pawn is not half open
pi->halfOpenFiles[us] &= ~(1 << f);
@@ -230,57 +226,66 @@ PawnInfo *PawnInfoTable::get_pawn_info(const Position &pos) {
isolated = pos.pawn_is_isolated(us, s);
doubled = pos.pawn_is_doubled(us, s);
- if (EvaluatePawnStorms)
+ // We calculate kingside and queenside pawn storm
+ // scores for both colors. These are used when evaluating
+ // middle game positions with opposite side castling.
+ //
+ // Each pawn is given a base score given by a piece square table
+ // (KStormTable[] or QStormTable[]). Pawns which seem to have good
+ // chances of creating an open file by exchanging itself against an
+ // enemy pawn on an adjacent file gets an additional bonus.
+
+ // Kingside pawn storms
+ bonus = KStormTable[relative_square(us, s)];
+ if (f >= FILE_F)
{
- // We calculate kingside and queenside pawn storm scores
- // for both colors. These are used when evaluating middle
- // game positions with opposite side castling.
- //
- // Each pawn is given a base score given by a piece square table
- // (KStormTable[] or QStormTable[]). This score is increased if
- // there are enemy pawns on adjacent files in front of the pawn.
- // This is because we want to be able to open files against the
- // enemy king, and to avoid blocking the pawn structure (e.g. white
- // pawns on h6, g5, black pawns on h7, g6, f7).
-
- // Kingside and queenside pawn storms
- int KBonus = KStormTable[relative_square(us, s)];
- int QBonus = QStormTable[relative_square(us, s)];
- bool outPost = (KBonus > 0 && (outpost_mask(us, s) & theirPawns));
- bool passed = (QBonus > 0 && (passed_pawn_mask(us, s) & theirPawns));
-
- switch (f) {
-
- case FILE_A:
- QBonus += passed * QBonus / 2;
- break;
-
- case FILE_B:
- QBonus += passed * (QBonus / 2 + QBonus / 4);
- break;
-
- case FILE_C:
- QBonus += passed * QBonus / 2;
- break;
-
- case FILE_F:
- KBonus += outPost * KBonus / 4;
- break;
-
- case FILE_G:
- KBonus += outPost * (KBonus / 2 + KBonus / 4);
- break;
-
- case FILE_H:
- KBonus += outPost * KBonus / 2;
- break;
-
- default:
- break;
+ Bitboard b = outpost_mask(us, s) & theirPawns & (FileFBB | FileGBB | FileHBB);
+ while (b)
+ {
+ Square s2 = pop_1st_bit(&b);
+ if (!(theirPawns & neighboring_files_bb(s2) & rank_bb(s2)))
+ {
+ // The enemy pawn has no pawn beside itself, which makes it
+ // particularly vulnerable. Big bonus, especially against a
+ // weakness on the rook file.
+ if (square_file(s2) == FILE_H)
+ bonus += 4*StormLeverBonus[f] - 8*square_distance(s, s2);
+ else
+ bonus += 2*StormLeverBonus[f] - 4*square_distance(s, s2);
+ } else
+ // There is at least one enemy pawn beside the enemy pawn we look
+ // at, which means that the pawn has somewhat better chances of
+ // defending itself by advancing. Smaller bonus.
+ bonus += StormLeverBonus[f] - 2*square_distance(s, s2);
}
- pi->ksStormValue[us] += KBonus;
- pi->qsStormValue[us] += QBonus;
}
+ pi->ksStormValue[us] += bonus;
+
+ // Queenside pawn storms
+ bonus = QStormTable[relative_square(us, s)];
+ if (f <= FILE_C)
+ {
+ Bitboard b = outpost_mask(us, s) & theirPawns & (FileABB | FileBBB | FileCBB);
+ while (b)
+ {
+ Square s2 = pop_1st_bit(&b);
+ if (!(theirPawns & neighboring_files_bb(s2) & rank_bb(s2)))
+ {
+ // The enemy pawn has no pawn beside itself, which makes it
+ // particularly vulnerable. Big bonus, especially against a
+ // weakness on the rook file.
+ if (square_file(s2) == FILE_A)
+ bonus += 4*StormLeverBonus[f] - 16*square_distance(s, s2);
+ else
+ bonus += 2*StormLeverBonus[f] - 8*square_distance(s, s2);
+ } else
+ // There is at least one enemy pawn beside the enemy pawn we look
+ // at, which means that the pawn has somewhat better chances of
+ // defending itself by advancing. Smaller bonus.
+ bonus += StormLeverBonus[f] - 4*square_distance(s, s2);
+ }
+ }
+ pi->qsStormValue[us] += bonus;
// Member of a pawn chain (but not the backward one)? We could speed up
// the test a little by introducing an array of masks indexed by color
@@ -377,7 +382,7 @@ PawnInfo *PawnInfoTable::get_pawn_info(const Position &pos) {
mgValue[us] += mv;
egValue[us] += ev;
-
+
// If the pawn is passed, set the square of the pawn in the passedPawns
// bitboard
if (passed)