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-rwxr-xr-xsrc/chess.h22
-rwxr-xr-xsrc/search.c24
-rw-r--r--src/searchsup.c75
-rwxr-xr-xsrc/split.c87
4 files changed, 111 insertions, 97 deletions
diff --git a/src/chess.h b/src/chess.h
index 367100f..8a1185a 100755
--- a/src/chess.h
+++ b/src/chess.h
@@ -935,6 +935,8 @@ typedef struct _SPLIT_INFO
INT iPositionExtend; // positional extension
SCORE iAlpha; // original alpha at split
SCORE iBeta; // beta at split
+ SCORE iEval; // static eval at split
+ SCORE iImprovement; // eval improvement since ply-2 (may be negative)
CUMULATIVE_SEARCH_FLAGS sSearchFlags; // flags at split time
// output from the split node
@@ -2399,20 +2401,21 @@ InitLMRTable(void);
INT
GetLMRReduction(IN SCORE iRoughEval,
- IN SCORE iAlpha,
- IN SCORE iBeta,
- IN SEARCHER_THREAD_CONTEXT *ctx,
- IN ULONG uRemainingDepth,
- IN ULONG uLegalMoves,
- IN MOVE mv,
- IN ULONG uMoveNum,
- IN INT iExtend);
+ IN SCORE iAlpha,
+ IN SCORE iBeta,
+ IN SCORE iImprovement,
+ IN SEARCHER_THREAD_CONTEXT *ctx,
+ IN ULONG uRemainingDepth,
+ IN ULONG uLegalMoves,
+ IN MOVE mv,
+ IN ULONG uMoveNum,
+ IN INT iExtend);
FLAG
WeShouldTryNullmovePruning(IN SEARCHER_THREAD_CONTEXT *ctx,
IN SCORE iAlpha,
IN SCORE iBeta,
- IN SCORE iRoughEval,
+ IN SCORE iEval,
IN SCORE iImprovement,
IN ULONG uNullDepth);
@@ -2914,6 +2917,7 @@ SCORE
StartParallelSearch(IN SEARCHER_THREAD_CONTEXT *ctx,
IN OUT SCORE *piAlpha,
IN SCORE iBeta,
+ IN SCORE iImprovement,
IN OUT SCORE *piBestScore,
IN OUT MOVE *pmvBest,
IN ULONG uMoveNum,
diff --git a/src/search.c b/src/search.c
index 3879d9f..4a153aa 100755
--- a/src/search.c
+++ b/src/search.c
@@ -165,7 +165,7 @@ Search(IN SEARCHER_THREAD_CONTEXT *ctx,
MOVE mvLast = (pi-1)->mv;
SCORE iBestScore = -INFINITY;
SCORE iInitialAlpha;
- SCORE iRoughEval;
+ SCORE iEval;
MOVE mv, mvBest, mvHash;
ULONG x = 0;
SCORE iScore;
@@ -337,19 +337,21 @@ Search(IN SEARCHER_THREAD_CONTEXT *ctx,
}
// Maybe do nullmove pruning
- pi->iEval = iRoughEval = GetRoughEvalScore(ctx, iAlpha, iBeta, FALSE);
+ pi->iEval = iEval = GetRoughEvalScore(ctx, iAlpha, iBeta, FALSE);
SCORE iImprovement = 0;
if (ctx->uPly > 1)
{
- iImprovement = (iRoughEval - ctx->sPlyInfo[ctx->uPly - 2].iEval);
+ iImprovement = (iEval - ctx->sPlyInfo[ctx->uPly - 2].iEval);
}
+
+
GENERATE_NO_MOVES;
if (!fSkipNull &&
!fThreat &&
WeShouldTryNullmovePruning(ctx,
iAlpha,
iBeta,
- iRoughEval,
+ iEval,
iImprovement,
uNextDepth))
{
@@ -525,16 +527,16 @@ Search(IN SEARCHER_THREAD_CONTEXT *ctx,
{
ASSERT(uDepth >= THREE_QUARTERS_PLY);
if ((uDepth <= ONE_PLY + THREE_QUARTERS_PLY) &&
- (iRoughEval + VALUE_KNIGHT <= iAlpha))
+ (iEval + VALUE_KNIGHT + iImprovement <= iAlpha))
{
- uFutilityMargin = (iAlpha - iRoughEval) / 2;
+ uFutilityMargin = (iAlpha - iEval) / 2;
ASSERT(uFutilityMargin);
}
else if ((uDepth > ONE_PLY + THREE_QUARTERS_PLY) &&
(uDepth <= TWO_PLY + THREE_QUARTERS_PLY) &&
- (iRoughEval + VALUE_ROOK <= iAlpha))
+ (iEval + VALUE_ROOK + iImprovement <= iAlpha))
{
- uFutilityMargin = (iAlpha - iRoughEval) / 2;
+ uFutilityMargin = (iAlpha - iEval) / 2;
ASSERT(uFutilityMargin);
}
}
@@ -649,6 +651,7 @@ Search(IN SEARCHER_THREAD_CONTEXT *ctx,
iScore = StartParallelSearch(ctx,
&iAlpha,
iBeta,
+ iImprovement,
&iBestScore,
&mvBest,
(x - 1),
@@ -703,7 +706,7 @@ Search(IN SEARCHER_THREAD_CONTEXT *ctx,
iAlpha,
iBeta,
(x - 1), // Note: x==0 if doing mvHash
- iRoughEval,
+ iEval,
uDepth,
iCheckSee,
&iExtend);
@@ -721,9 +724,10 @@ Search(IN SEARCHER_THREAD_CONTEXT *ctx,
// Decide how much (if any) to reduce this move's depth --
// graded LMR.
{
- INT iLMR = GetLMRReduction(iRoughEval,
+ INT iLMR = GetLMRReduction(iEval,
iAlpha,
iBeta,
+ iImprovement,
ctx,
uDepth,
uLegalMoves,
diff --git a/src/searchsup.c b/src/searchsup.c
index d2cbbbd..9ad4303 100644
--- a/src/searchsup.c
+++ b/src/searchsup.c
@@ -188,15 +188,16 @@ ThreadUnderTerminatingSplit(IN SEARCHER_THREAD_CONTEXT *ctx)
INT
-GetLMRReduction(IN SCORE iRoughEval,
- IN SCORE iAlpha,
- IN SCORE iBeta,
- IN SEARCHER_THREAD_CONTEXT *ctx,
- IN ULONG uRemainingDepth,
- IN ULONG uLegalMoves,
- IN MOVE mv,
- IN ULONG uMoveNum,
- IN INT iExtend)
+GetLMRReduction(IN SCORE iEval,
+ IN SCORE iAlpha,
+ IN SCORE iBeta,
+ IN SCORE iImprovement,
+ IN SEARCHER_THREAD_CONTEXT *ctx,
+ IN ULONG uRemainingDepth,
+ IN ULONG uLegalMoves,
+ IN MOVE mv,
+ IN ULONG uMoveNum,
+ IN INT iExtend)
/**
Routine description:
@@ -206,6 +207,8 @@ Routine description:
counter-move exemption. Kept under the GetLMRReduction name so
search.c/split.c's call sites need no changes.
+ Note: the move has already been made by the time we get here.
+
Return value:
INT : 0 if no reduction, else -ONE_PLY.
@@ -215,6 +218,7 @@ Return value:
ASSERT(ctx->uPly > 0);
ASSERT(mv.uMove);
ASSERT((uMoveNum > 0) || (uLegalMoves == 0));
+
if ((uRemainingDepth >= TWO_PLY) &&
(FALSE == ctx->sPlyInfo[ctx->uPly - 1].fPvNode) &&
(uLegalMoves > 5) &&
@@ -230,6 +234,9 @@ Return value:
(GetMoveFailHighPercentage(mv, NULL) <= 10))
{
ASSERT(!InCheck(&ctx->sPosition, ctx->sPosition.uToMove));
+ if (iImprovement <= 40) {
+ return(-(ONE_PLY + QUARTER_PLY));
+ }
return(-ONE_PLY);
}
return(0);
@@ -369,15 +376,14 @@ Return value:
}
-void
-ComputeMoveExtension(IN SEARCHER_THREAD_CONTEXT *ctx,
- IN SCORE iAlpha,
- IN SCORE iBeta,
- IN ULONG uMoveNum,
- IN SCORE iRoughEval,
- IN ULONG uDepth,
- IN SCORE iCheckSee,
- IN OUT INT *piExtend)
+void ComputeMoveExtension(IN SEARCHER_THREAD_CONTEXT *ctx,
+ IN SCORE iAlpha,
+ IN SCORE iBeta,
+ IN ULONG uMoveNum,
+ IN SCORE iRoughEval,
+ IN ULONG uDepth,
+ IN SCORE iCheckSee,
+ IN OUT INT *piExtend)
/**
Routine description:
@@ -482,13 +488,13 @@ Return value:
{
ASSERT(IS_ESCAPING_CHECK(mv));
iMoveScore = iRoughEval + ComputeMoveScore(ctx, mv, uMoveNum);
-
+
// One legal move in reply to check...
if (ONE_LEGAL_MOVE(ctx, ctx->uPly - 1) &&
- CountKingSafetyDefects(&ctx->sPosition, uColor) > 1)
+ CountKingSafetyDefects(&ctx->sPosition, uColor) > 1)
{
*piExtend += (QUARTER_PLY +
- HALF_PLY *
+ HALF_PLY *
(iMoveScore + VALUE_KNIGHT > iAlpha));
INC(ctx->sCounters.extension.uOneLegalMove);
}
@@ -511,7 +517,7 @@ Return value:
{
// Endgame extension
if ((ctx->sPlyInfo[1].uTotalNonPawns > 2) &&
- ((pos->uNonPawnCount[BLACK][0] +
+ ((pos->uNonPawnCount[BLACK][0] +
pos->uNonPawnCount[WHITE][0]) == 2))
{
if ((mv.pCaptured && !IS_PAWN(mv.pCaptured)) ||
@@ -529,7 +535,7 @@ Return value:
if (uDepth <= THREE_PLY)
{
if ((mv.pCaptured) && !IS_PAWN(mv.pCaptured) &&
- ((PIECE_VALUE(mv.pCaptured) ==
+ ((PIECE_VALUE(mv.pCaptured) ==
PIECE_VALUE(mvLast.pCaptured)) ||
((mvLast.pPromoted) && (mv.cTo == mvLast.cTo))))
{
@@ -1092,11 +1098,11 @@ SelectNullmoveRFactor(SEARCHER_THREAD_CONTEXT *ctx,
FLAG WeShouldTryNullmovePruning(SEARCHER_THREAD_CONTEXT *ctx,
SCORE iAlpha,
SCORE iBeta,
- SCORE iRoughEval,
- SCORE iImprovement,
- ULONG uNullDepth)
+ SCORE iEval,
+ SCORE iImprovement,
+ ULONG uNullDepth)
{
- static SCORE iSkipNullMargins[] = {
+ static SCORE iSkipShallowNullIfThisFarBelowAlpha[] = {
700, 950, 1110, 1150, 1190, 1230, 1270, 0
};
POSITION *pos = &ctx->sPosition;
@@ -1113,20 +1119,17 @@ FLAG WeShouldTryNullmovePruning(SEARCHER_THREAD_CONTEXT *ctx,
(pos->uNonPawnCount[pos->uToMove][0] > 2) &&
(FALSE == pi->fInCheck) &&
(iBeta != +INFINITY) &&
- (FALSE == pi->fPvNode)) // <--- TODO: test this one please...
+ (FALSE == pi->fPvNode))
{
if (uNullDepth <= 6 * ONE_PLY)
{
u = uNullDepth / ONE_PLY;
ASSERT(u <= 6);
- SCORE iMargin = iSkipNullMargins[u];
- if (iImprovement > 0)
- {
- iMargin -= iImprovement;
- iMargin = MAX(0, iMargin);
- }
- if ((iRoughEval + iMargin <= iAlpha) ||
- ((iRoughEval + iMargin / 2 <= iAlpha) &&
+ SCORE iMargin = iSkipShallowNullIfThisFarBelowAlpha[u];
+ iMargin -= iImprovement; // Note: if improving, makes null more likely
+ iMargin = MAX(0, iMargin); // if not, less likely.
+ if ((iEval + iMargin <= iAlpha) ||
+ ((iEval + iMargin / 2 <= iAlpha) &&
(ValueOfMaterialInTroubleAfterNull(ctx, pos->uToMove))))
{
return FALSE;
diff --git a/src/split.c b/src/split.c
index 8bc4e60..b3fc659 100755
--- a/src/split.c
+++ b/src/split.c
@@ -246,7 +246,7 @@ Return value:
v++)
{
ctx->sMoveStack.mvf[v] = g_SplitInfo[u].mvf[v];
- ASSERT(SanityCheckMove(&ctx->sPosition,
+ ASSERT(SanityCheckMove(&ctx->sPosition,
g_SplitInfo[u].mvf[v].mv));
}
@@ -459,6 +459,7 @@ SCORE
StartParallelSearch(IN SEARCHER_THREAD_CONTEXT *ctx,
IN OUT SCORE *piAlpha,
IN SCORE iBeta,
+ IN SCORE iImprovement,
IN OUT SCORE *piBestScore,
IN OUT MOVE *pmvBest,
IN ULONG uMoveNum,
@@ -565,6 +566,8 @@ Return value:
memcpy(&(g_SplitInfo[u].sRootPosition),
GetRootPosition(),
sizeof(POSITION));
+ g_SplitInfo[u].iEval = ctx->sPlyInfo[ctx->uPly].iEval;
+ g_SplitInfo[u].iImprovement = iImprovement;
#if DEBUG
g_SplitInfo[u].uSplitPly = ctx->uPly;
memcpy(&(g_SplitInfo[u].sSplitPosition),
@@ -579,7 +582,7 @@ Return value:
// useless. Before we grab any helper threads, see if we
// need to bail out of this split.
//
- if (g_MoveTimer.bvFlags & TIMER_STOPPING)
+ if (g_MoveTimer.bvFlags & TIMER_STOPPING)
{
g_uNumSplitsAvailable++;
g_SplitInfo[u].uNumThreadsHelping = 0;
@@ -690,11 +693,11 @@ Return value:
// Update the context of the thread that is initiating the
// split with a pointer to the split info node we are using.
//
- for (uSplitNum = 0;
- uSplitNum < NUM_SPLIT_PTRS_IN_CONTEXT;
- uSplitNum++)
+ for (uSplitNum = 0;
+ uSplitNum < NUM_SPLIT_PTRS_IN_CONTEXT;
+ uSplitNum++)
{
- if (ctx->pSplitInfo[uSplitNum] == NULL)
+ if (ctx->pSplitInfo[uSplitNum] == NULL)
{
ctx->pSplitInfo[uSplitNum] = &(g_SplitInfo[u]);
break;
@@ -726,7 +729,7 @@ Return value:
if (g_fExitProgram) break;
}
- //
+ //
// Note: past this point we are the only ones using the
// split until we return it to the pool by making its
// refcount zero again.
@@ -848,7 +851,7 @@ Parameters:
MOVE mv : move it just searched
SCORE iScore : score of the move's subtree
ULONG u : split node number
-
+
Return value:
static void
@@ -856,13 +859,13 @@ Return value:
**/
{
ULONG v;
-
+
AcquireSpinLock(&(g_SplitInfo[u].uLock));
//
// See if this split is shutting down
//
- if (TRUE == g_SplitInfo[u].fTerminate)
+ if (TRUE == g_SplitInfo[u].fTerminate)
{
ReleaseSpinLock(&(g_SplitInfo[u].uLock));
return;
@@ -909,8 +912,8 @@ Return value:
}
-static void
-_SetFinalStats(IN SEARCHER_THREAD_CONTEXT *ctx,
+static void
+_SetFinalStats(IN SEARCHER_THREAD_CONTEXT *ctx,
IN ULONG u)
/**
@@ -934,13 +937,13 @@ Return value:
// Before we stop searching this node, update some stuff.
//
AcquireSpinLock(&(g_SplitInfo[u].uLock));
-
+
//
// Counters to persist in the main counter struct via the split.
//
- g_SplitInfo[u].sCounters.tree.u64TotalNodeCount +=
+ g_SplitInfo[u].sCounters.tree.u64TotalNodeCount +=
ctx->sCounters.tree.u64TotalNodeCount;
- g_SplitInfo[u].sCounters.tree.u64BetaCutoffs +=
+ g_SplitInfo[u].sCounters.tree.u64BetaCutoffs +=
ctx->sCounters.tree.u64BetaCutoffs;
g_SplitInfo[u].sCounters.tree.u64BetaCutoffsOnFirstMove +=
ctx->sCounters.tree.u64BetaCutoffsOnFirstMove;
@@ -954,11 +957,11 @@ Return value:
//
// TODO: Any other counters we care about?
//
-
+
//
// IDEA: Save the killers from this context to bring back to main
//
-
+
//
// Decrement threadcount in this split. Note: the main thread
// incremented it by two.
@@ -970,18 +973,18 @@ Return value:
}
-static MOVE
-_GetNextParallelMove(OUT SCORE *piAlpha,
- OUT SCORE *piBestScore,
+static MOVE
+_GetNextParallelMove(OUT SCORE *piAlpha,
+ OUT SCORE *piBestScore,
OUT ULONG *puMoveNumber,
IN ULONG u)
/**
-
+
Routine description:
Retrieve the next parallel move to search at the split node. Also
update alpha and bestscore.
-
+
Parameters:
SCORE *piAlpha : current alpha
@@ -995,7 +998,7 @@ Return value:
**/
{
MOVE mv = {0};
-
+
AcquireSpinLock(&(g_SplitInfo[u].uLock));
if (g_SplitInfo[u].fTerminate)
{
@@ -1012,7 +1015,7 @@ Return value:
#ifdef DEBUG
ASSERT(!(g_SplitInfo[u].mvf[g_SplitInfo[u].uOnDeckMove].bvFlags &
MVF_MOVE_SEARCHED));
- g_SplitInfo[u].mvf[g_SplitInfo[u].uOnDeckMove].bvFlags |=
+ g_SplitInfo[u].mvf[g_SplitInfo[u].uOnDeckMove].bvFlags |=
MVF_MOVE_SEARCHED;
ASSERT(mv.uMove);
ASSERT(SanityCheckMove(&g_SplitInfo[u].sSplitPosition, mv));
@@ -1029,8 +1032,8 @@ Return value:
}
-void
-HelpSearch(IN OUT SEARCHER_THREAD_CONTEXT *ctx,
+void
+HelpSearch(IN OUT SEARCHER_THREAD_CONTEXT *ctx,
IN ULONG u)
/**
@@ -1063,7 +1066,7 @@ Return value:
SCORE iCheckSee;
#ifdef DEBUG
POSITION board;
-
+
memcpy(&board, &ctx->sPosition, sizeof(POSITION));
ASSERT(PositionsAreEquivalent(&board, &g_SplitInfo[u].sSplitPosition));
#endif
@@ -1072,21 +1075,24 @@ Return value:
iBeta = g_SplitInfo[u].iBeta;
uOrigDepth = g_SplitInfo[u].uDepth;
ctx->sSearchFlags = g_SplitInfo[u].sSearchFlags;
+ SCORE iEval = g_SplitInfo[u].iEval;
+ SCORE iImprovement = g_SplitInfo[u].iImprovement;
+
do
{
iExtend = iOrigExtend;
uDepth = uOrigDepth;
ASSERT(ctx->uPly == g_SplitInfo[u].uSplitPly);
-
+
mv = _GetNextParallelMove(&iAlpha,
- &iBestScore,
+ &iBestScore,
&uMoveNum,
u);
if (mv.uMove == 0) break; // Split is terminating
ASSERT(IS_VALID_SCORE(iBestScore));
ASSERT(uMoveNum < MAX_MOVES_PER_PLY);
- ASSERT(IS_SAME_MOVE(mv,
+ ASSERT(IS_SAME_MOVE(mv,
ctx->sMoveStack.mvf[ctx->sMoveStack.uBegin[ctx->uPly]+uMoveNum].mv));
ASSERT(uDepth <= MAX_DEPTH_PER_SEARCH);
ASSERT(IS_VALID_SCORE(iAlpha));
@@ -1094,7 +1100,7 @@ Return value:
ASSERT(iAlpha < iBeta);
ASSERT(iExtend >= -ONE_PLY);
ASSERT(iExtend <= +ONE_PLY);
-
+
// SEE on the PRE-move position -- see search.c's identical comment.
iCheckSee = 0;
if (IS_CHECKING_MOVE(mv))
@@ -1105,25 +1111,21 @@ Return value:
uMoveNum);
}
- if (MakeMove(ctx, mv))
+ if (TRUE == MakeMove(ctx, mv))
{
- ASSERT((IS_CHECKING_MOVE(mv) &&
- InCheck(&ctx->sPosition, ctx->sPosition.uToMove)) ||
- (!IS_CHECKING_MOVE(mv) &&
- !InCheck(&ctx->sPosition, ctx->sPosition.uToMove)));
- iRoughEval = GetRoughEvalScore(ctx, iAlpha, iBeta, TRUE);
+ ASSERT((IS_CHECKING_MOVE(mv) && InCheck(&ctx->sPosition, ctx->sPosition.uToMove)) ||
+ (!IS_CHECKING_MOVE(mv) && !InCheck(&ctx->sPosition, ctx->sPosition.uToMove)));
// Compute extension
ComputeMoveExtension(ctx,
iAlpha,
iBeta,
- (ctx->sMoveStack.uBegin[ctx->uPly - 1] +
- uMoveNum),
- iRoughEval,
+ (ctx->sMoveStack.uBegin[ctx->uPly - 1] + uMoveNum),
+ iEval,
uDepth,
iCheckSee,
&iExtend);
-
+
//
// Cap total extension plies spent on this line, same as the
// non-split move loop in search.c does.
@@ -1139,9 +1141,10 @@ Return value:
// Decide how much (if any) to reduce this move's depth.
//
{
- INT iLMR = GetLMRReduction(iRoughEval,
+ INT iLMR = GetLMRReduction(iEval,
iAlpha,
iBeta,
+ iImprovement,
ctx,
uDepth,
(g_SplitInfo[u].uAlreadyDone +
generated by cgit v1.3 (git 2.53.0) at 2026-09-09 13:44:42 +0000