Eval mobility/pseudo-mobility tweaks; drop unproductive move-ordering experiments.

eval.c: add bishop/rook x-ray pseudo-mobility terms (squares seen past a
directly-attacked higher-value piece), trim pawn-centrality edge penalty
and bishop-pair bonus.

chess.h/dynamic.c/generate.c/search.c/searchsup.c: revert three move-ordering
experiments (recapture bonus, flee-to-safety GOOD_MOVE promotion, ply-2
move-pair bonus) that calibrated with real fail-high signal but never
converted into a measurable node-count or solve-rate win on the curated
suites -- see MOVE_ORDERING_IDEAS.md for the evidence and reasoning behind
each drop. Add MOVE_ORDERING_EVIDENCE_COLLECTION as its own GNUmakefile
flag, independent of PERF_COUNTERS, for any future such harness.

command.c: remove the KING_DEFECT_DUMP-gated evalkingdump command, dead
since the king-safety remine work moved to eval_tune/king_safety_data/.

Co-Authored-By: Claude Sonnet 5 <[email protected]>

1 files changed, 27 insertions, 81 deletions

diff --git a/src/dynamic.c b/src/dynamic.c
index b0bad91..a56cf29 100644
--- a/src/dynamic.c
+++ b/src/dynamic.c
@@ -389,6 +389,7 @@ Return value:
     }
     u = MOVE_TO_INDEX(mvLast);
 
+#ifdef MOVE_ORDERING_EVIDENCE_COLLECTION
     //
     // Hit-rate instrumentation: did the counter-move slot for this
     // previous move already predict the move that just won here?
@@ -397,13 +398,14 @@ Return value:
     if ((ctx->mvCounter[u][0].uMove != 0) ||
         (ctx->mvCounter[u][1].uMove != 0))
     {
-        INC(ctx->sCounters.tree.u64CounterMoveTries);
+        MOI_INC(ctx->sCounters.tree.u64CounterMoveTries);
         if (IS_SAME_MOVE(mv, ctx->mvCounter[u][0]) ||
             IS_SAME_MOVE(mv, ctx->mvCounter[u][1]))
         {
-            INC(ctx->sCounters.tree.u64CounterMoveHits);
+            MOI_INC(ctx->sCounters.tree.u64CounterMoveHits);
         }
     }
+#endif
 
     // A/B test: write-gating by depth (reject shallower overwrites)
     // measured *worse* hit rate with no EBF gain -- this table is
@@ -686,37 +688,18 @@ Return value:
 
 **/
 {
-    ULONG x, y;
-    ULONG uVal;
     ULONG *pu;
 
     ASSERT(!IS_CAPTURE_OR_PROMOTION(mv));
-    uVal = uDepth / ONE_PLY;
-    ASSERT(uVal >= 0);
-    ASSERT(uVal <= MAX_PLY_PER_SEARCH);
-    uVal += 1;
-    uVal *= uVal;
-    ASSERT(uVal > 0);
-
-    pu = &(g_HistoryCounters[mv.pMoved][mv.cTo]);
-    LOCK_DYN;
-    *pu += uVal;
 
     //
-    // Make sure that the history weight doesn't get large enough to
-    // affect the move flags or else our move ordering algorithm is
-    // screwed.
+    // EXPERIMENT: flat/saturating update (see HISTORY_MAX/
+    // HISTORY_UPDATE_SHIFT comment, chess.h) -- depth-independent,
+    // asymptotically approaches HISTORY_MAX, never exceeds it.
     //
-    while (*pu & ~STRIP_OFF_FLAGS)
-    {
-        for (x = 0; x <= WHITE_KING; x++)
-        {
-            FOREACH_SQUARE(y)
-            {
-                g_HistoryCounters[x][y] >>= 4;
-            }
-        }
-    }
+    pu = &(g_HistoryCounters[mv.pMoved][mv.cTo]);
+    LOCK_DYN;
+    *pu += (HISTORY_MAX - *pu) >> HISTORY_UPDATE_SHIFT;
 
 #ifdef MP
     //
@@ -734,14 +717,16 @@ Return value:
     UNLOCK_DYN;
 }
 
-static void 
-_DecrementMoveHistoryCounter(MOVE mv, 
+static void
+_DecrementMoveHistoryCounter(MOVE mv,
                              ULONG uDepth)
 /**
-  
+
 Routine description:
 
     Decrease a move's history counter in the global history table.
+    EXPERIMENT: flat/saturating decay, depth-independent -- see
+    HISTORY_MAX/HISTORY_UPDATE_SHIFT comment in chess.h.
 
 Parameters:
 
@@ -754,27 +739,14 @@ Return value:
 
 **/
 {
-    ULONG uVal;
     ULONG *pu;
 
     ASSERT(!IS_CAPTURE_OR_PROMOTION(mv));
-    uVal = uDepth / ONE_PLY;
-    ASSERT(uVal >= 0);
-    ASSERT(uVal <= MAX_PLY_PER_SEARCH);
-    uVal /= 4;
-    uVal += 1;
-    ASSERT(uVal > 0);
+    ASSERT(uDepth <= MAX_PLY_PER_SEARCH * ONE_PLY); // param kept for signature parity w/ increment
 
     pu = &(g_HistoryCounters[mv.pMoved][mv.cTo]);
     LOCK_DYN;
-    if (*pu >= uVal)
-    {
-        *pu -= uVal;
-    }
-    else
-    {
-        *pu = 0;
-    }
+    *pu -= (*pu >> HISTORY_UPDATE_SHIFT);
     _RecordMoveFailure(mv);
     UNLOCK_DYN;
 }
@@ -787,9 +759,9 @@ _IncrementContinuationCounter(MOVE mvPrev, MOVE mv, ULONG uRemainingDepth)
 Routine description:
 
     Continuation-history counterpart to _IncrementMoveHistoryCounter --
-    same (depth+1)^2 growth, same overflow-driven rescale, but keyed by
-    (mvPrev, mv) instead of mv alone. No-op if there was no previous
-    move (root).
+    EXPERIMENT: same flat/saturating depth-independent update (see
+    HISTORY_MAX/HISTORY_UPDATE_SHIFT, chess.h), keyed by (mvPrev, mv)
+    instead of mv alone. No-op if there was no previous move (root).
 
 Parameters:
 
@@ -803,33 +775,19 @@ Return value:
 
 **/
 {
-    ULONG uVal;
     ULONG *pu;
-    ULONG x;
 
     ASSERT(!IS_CAPTURE_OR_PROMOTION(mv));
     if (0 == mvPrev.uMove)
     {
         return;
     }
-    uVal = uRemainingDepth / ONE_PLY;
-    ASSERT(uVal >= 0);
-    ASSERT(uVal <= MAX_PLY_PER_SEARCH);
-    uVal += 1;
-    uVal *= uVal;
-    ASSERT(uVal > 0);
+    ASSERT(uRemainingDepth <= MAX_PLY_PER_SEARCH * ONE_PLY); // unused by design now
 
     pu = &(g_ContinuationHistory[(MOVE_TO_CONT_KEY(mvPrev) * CONT_KEY_RANGE) +
                                   MOVE_TO_CONT_KEY(mv)]);
     LOCK_DYN;
-    *pu += uVal;
-    while (*pu & ~STRIP_OFF_FLAGS)
-    {
-        for (x = 0; x < CONTINUATION_TABLE_SIZE; x++)
-        {
-            g_ContinuationHistory[x] >>= 4;
-        }
-    }
+    *pu += (HISTORY_MAX - *pu) >> HISTORY_UPDATE_SHIFT;
     UNLOCK_DYN;
 }
 
@@ -840,8 +798,9 @@ _DecrementContinuationCounter(MOVE mvPrev, MOVE mv, ULONG uRemainingDepth)
 
 Routine description:
 
-    Continuation-history counterpart to _DecrementMoveHistoryCounter.
-    No-op if there was no previous move (root).
+    Continuation-history counterpart to _DecrementMoveHistoryCounter --
+    EXPERIMENT: flat/saturating decay, depth-independent. No-op if there
+    was no previous move (root).
 
 Parameters:
 
@@ -855,7 +814,6 @@ Return value:
 
 **/
 {
-    ULONG uVal;
     ULONG *pu;
 
     ASSERT(!IS_CAPTURE_OR_PROMOTION(mv));
@@ -863,24 +821,12 @@ Return value:
     {
         return;
     }
-    uVal = uRemainingDepth / ONE_PLY;
-    ASSERT(uVal >= 0);
-    ASSERT(uVal <= MAX_PLY_PER_SEARCH);
-    uVal /= 4;
-    uVal += 1;
-    ASSERT(uVal > 0);
+    ASSERT(uRemainingDepth <= MAX_PLY_PER_SEARCH * ONE_PLY); // unused by design now
 
     pu = &(g_ContinuationHistory[(MOVE_TO_CONT_KEY(mvPrev) * CONT_KEY_RANGE) +
                                   MOVE_TO_CONT_KEY(mv)]);
     LOCK_DYN;
-    if (*pu >= uVal)
-    {
-        *pu -= uVal;
-    }
-    else
-    {
-        *pu = 0;
-    }
+    *pu -= (*pu >> HISTORY_UPDATE_SHIFT);
     UNLOCK_DYN;
 }