Plumb iImprovement into LMR and futiltiy and parallel search.

Fix a bug (iEval) in HelpSearch
This commit changes the heuristics for: nullmove pruning, LMR, and EFP slightly.

1 files changed, 13 insertions, 9 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,