Increase PV LMR to SF 1.8 levels

Non-PV LMR is left unchanged.

After 8819 games
Mod- Orig:  1442 - 1343 - 6034 ELO +3 (+- 2.9) LOS 86%

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

diff --git a/src/search.cpp b/src/search.cpp
index 66a27fa683a91c5345b4f1beace887f5684f6cd0..12481d4083bae3fc6d48cfb733938ec91acd595b 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -347,7 +347,7 @@ void init_search() {
   // Init reductions array
   for (hd = 1; hd < 64; hd++) for (mc = 1; mc < 64; mc++)
   {
-      double    pvRed = 0.33 + log(double(hd)) * log(double(mc)) / 4.5;
+      double    pvRed = log(double(hd)) * log(double(mc)) / 3.0;
       double nonPVRed = 0.33 + log(double(hd)) * log(double(mc)) / 2.25;
       ReductionMatrix[PV][hd][mc]    = (int8_t) (   pvRed >= 1.0 ? floor(   pvRed * int(ONE_PLY)) : 0);
       ReductionMatrix[NonPV][hd][mc] = (int8_t) (nonPVRed >= 1.0 ? floor(nonPVRed * int(ONE_PLY)) : 0);