Add LMR with PV-adjacency guard (v7), verified against saved binary

Late Move Reductions using a depth x movecount table (Ethereal-style
formula), gated off PV nodes and the ply directly below a PV node
(PLY_INFO.fIsPVNode), with magnitude-aware re-search on fail-high.
Verified node-for-node identical to the previously tested-good v7
binary on a canary position (sd 10) after reconstructing from a ZFS
snapshot of search.c/root.c/split.c taken just before that binary was
built.

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

1 files changed, 11 insertions, 0 deletions

diff --git a/src/root.c b/src/root.c
index aa678b1..7c50a65 100755
--- a/src/root.c
+++ b/src/root.c
@@ -456,6 +456,17 @@ Return value:
     ASSERT(d);
     Trace("Null move cutoff rate: %5.3f percent.\n",
           ((n / d) * 100.0));
+    n = (double)(ctx->sCounters.tree.u64HistoryPruneReSearches);
+    d = (double)(ctx->sCounters.tree.u64HistoryPrunes) + 1;
+    Trace("History/LMR pruning: %"COMPILER_LONGLONG_UNSIGNED_FORMAT
+          " reduced, %5.3f percent needed a full-depth re-search.\n",
+          ctx->sCounters.tree.u64HistoryPrunes, ((n / d) * 100.0));
+    n = (double)(ctx->sCounters.tree.u64FutilityPrunes);
+    d = (double)(ctx->sCounters.tree.u64FutilityCandidates) + 1;
+    Trace("Futility pruning: %"COMPILER_LONGLONG_UNSIGNED_FORMAT
+          " candidates, %5.3f percent actually pruned "
+          "(rest saved by fail-high%% / SEE gates).\n",
+          ctx->sCounters.tree.u64FutilityCandidates, ((n / d) * 100.0));
     if (ctx->sCounters.egtb.uProbes > 0)
     {
         n = (double)(ctx->sCounters.egtb.uHits);