In razor qsearch use corrected beta

Correct beta by razor margin when callin qsearch

After 1019 games on Joona's QUAD

Mod - Orig: 524 - 495 (+10 elo)

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

diff --git a/src/search.cpp b/src/search.cpp
index e02529327435b46f49f4780d591877b201042cbf..76a88643307aa4138c58415d8955f6bb147aed5d 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1360,8 +1360,9 @@ namespace {
              && ttMove == MOVE_NONE
              && !pos.has_pawn_on_7th(pos.side_to_move()))
     {
              && ttMove == MOVE_NONE
              && !pos.has_pawn_on_7th(pos.side_to_move()))
     {

-        Value v = qsearch(pos, ss, beta-1, beta, Depth(0), ply, threadID);
-        if (v < beta - RazorMargins[int(depth) - 2])
+        Value rbeta = beta - RazorMargins[int(depth) - 2];
+        Value v = qsearch(pos, ss, rbeta-1, rbeta, Depth(0), ply, threadID);
+        if (v < rbeta)

           return v;
     }
 
           return v;
     }