Stricter conditions in main search stand pat

Not a biggie but is a reduced pruned patch that doesn't
seems to hurt, so it is welcomed ;-)

After 999 games at 1+0
Mod vs Orig +207 =601 -191  +6 ELO

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

diff --git a/src/search.cpp b/src/search.cpp
index 8f7c4875d47e9690ef5d77c5f3e7e0629782ddfc..378c3d20f1f693d48ec2df4eba1a5ed68f6fc06e 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1497,10 +1497,9 @@ namespace {
 
     // Do a "stand pat". If we are above beta by a good margin then
     // return immediately.
-    // FIXME: test with added condition 'allowNullmove || depth <= OnePly' and !value_is_mate(beta)
-    // FIXME: test with modified condition 'depth < RazorDepth'
     if (  !isCheck
-        && depth < SelectiveDepth
+        && allowNullmove
+        && depth < RazorDepth
         && staticValue - FutilityMargins[int(depth)] >= beta)
         return staticValue - FutilityMargins[int(depth)];