Better self-document LMR reduction() formula

Suggested by Onno

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>

diff --git a/src/search.cpp b/src/search.cpp
index ff489c9627395a99109e89fbd0186c0359d1f5d4..6a42cc50b05a233bb181ac884bcefaec6268a062 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -216,7 +216,7 @@ namespace {
   int8_t ReductionMatrix[2][64][64]; // [pv][depth][moveNumber]
 
   template <NodeType PV>
   int8_t ReductionMatrix[2][64][64]; // [pv][depth][moveNumber]
 
   template <NodeType PV>

-  inline Depth reduction(Depth d, int mn) { return (Depth) ReductionMatrix[PV][Min(d / 2, 63)][Min(mn, 63)]; }
+  inline Depth reduction(Depth d, int mn) { return (Depth) ReductionMatrix[PV][Min(d / ONE_PLY, 63)][Min(mn, 63)]; }

 
   // Easy move margin. An easy move candidate must be at least this much
   // better than the second best move.
 
   // Easy move margin. An easy move candidate must be at least this much
   // better than the second best move.