From: Joona Kiiski <joona.kiiski@gmail.com>
Date: Mon, 4 Jan 2010 16:41:24 +0000 (+0200)
Subject: Slow down reductions
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=e2e360fcbc02e0ca3329a36766239e7175501103;hp=49b1c5dccd476229c06fd4a4b8dd94403c602396

Slow down reductions

After testing on Joona QUAD the whole LMR series:

Orig - Mod: 335 - 405 (+33 elo)

Functionality Signature: 12581900

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

diff --git a/src/search.cpp b/src/search.cpp
index ee21915d..8a8f9297 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -969,7 +969,7 @@ namespace {
                 && !captureOrPromotion
                 && !move_is_castle(move))
             {
-                double red = ln(RootMoveNumber - MultiPV + 1) * ln(depth / 2) / 3.0;
+                double red = 0.5 + ln(RootMoveNumber - MultiPV + 1) * ln(depth / 2) / 6.0;
                 if (red >= 1.0)
                 {
                     ss[0].reduction = Depth(int(floor(red * int(OnePly))));
@@ -1226,7 +1226,7 @@ namespace {
             && !move_is_castle(move)
             && !move_is_killer(move, ss[ply]))
         {
-          double red = ln(moveCount) * ln(depth / 2) / 3.0;
+          double red = 0.5 + ln(moveCount) * ln(depth / 2) / 6.0;
           if (red >= 1.0)
           {
               ss[ply].reduction = Depth(int(floor(red * int(OnePly))));
@@ -1557,7 +1557,7 @@ namespace {
           && !move_is_killer(move, ss[ply])
           /* && move != ttMove*/)
       {
-          double red = ln(moveCount) * ln(depth / 2) / 1.5;
+          double red = 0.5 + ln(moveCount) * ln(depth / 2) / 3.0;
           if (red >= 1.0)
           {
               ss[ply].reduction = Depth(int(floor(red * int(OnePly))));
@@ -1902,7 +1902,7 @@ namespace {
           && !move_is_castle(move)
           && !move_is_killer(move, ss[sp->ply]))
       {
-          double red = ln(moveCount) * ln(sp->depth / 2) / 1.5;
+          double red = 0.5 + ln(moveCount) * ln(sp->depth / 2) / 3.0;
           if (red >= 1.0)
           {
               ss[sp->ply].reduction = Depth(int(floor(red * int(OnePly))));
@@ -2013,7 +2013,7 @@ namespace {
           && !move_is_castle(move)
           && !move_is_killer(move, ss[sp->ply]))
       {
-          double red = ln(moveCount) * ln(sp->depth / 2) / 3.0;
+          double red = 0.5 + ln(moveCount) * ln(sp->depth / 2) / 6.0;
           if (red >= 1.0)
           {
               ss[sp->ply].reduction = Depth(int(floor(red * int(OnePly))));