Skip to content

Commit

Permalink
Retire EvaluatePawnStorms and UseEasyMove constants
Browse files Browse the repository at this point in the history
Merged from Glaurung 2.2

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
  • Loading branch information
mcostalba committed Dec 21, 2008
1 parent 61c6a3d commit 23490bd
Show file tree
Hide file tree
Showing 2 changed files with 53 additions and 63 deletions.
113 changes: 53 additions & 60 deletions src/pawns.cpp
Expand Up @@ -96,9 +96,6 @@ 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,
Expand Down Expand Up @@ -204,13 +201,12 @@ PawnInfo *PawnInfoTable::get_pawn_info(const Position &pos) {
Bitboard pawns = ourPawns;

// 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)
Expand All @@ -230,57 +226,54 @@ 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[]). 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;
}
pi->ksStormValue[us] += KBonus;
pi->qsStormValue[us] += QBonus;
// 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 outPostFlag = (KBonus > 0 && (outpost_mask(us, s) & theirPawns));
bool passedFlag = (QBonus > 0 && (passed_pawn_mask(us, s) & theirPawns));

switch (f) {

case FILE_A:
QBonus += passedFlag * QBonus / 2;
break;

case FILE_B:
QBonus += passedFlag * (QBonus / 2 + QBonus / 4);
break;

case FILE_C:
QBonus += passedFlag * QBonus / 2;
break;

case FILE_F:
KBonus += outPostFlag * KBonus / 4;
break;

case FILE_G:
KBonus += outPostFlag * (KBonus / 2 + KBonus / 4);
break;

case FILE_H:
KBonus += outPostFlag * KBonus / 2;
break;

default:
break;
}
pi->ksStormValue[us] += KBonus;
pi->qsStormValue[us] += QBonus;

// 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
Expand Down
3 changes: 0 additions & 3 deletions src/search.cpp
Expand Up @@ -133,9 +133,6 @@ namespace {
// when the static evaluation is at most IIDMargin below beta.
const Value IIDMargin = Value(0x100);

// Use easy moves?
const bool UseEasyMove = true;

// Easy move margin. An easy move candidate must be at least this much
// better than the second best move.
const Value EasyMoveMargin = Value(0x200);
Expand Down

0 comments on commit 23490bd

Please sign in to comment.