From: VoyagerOne <excelgeek@gmail.com>
Date: Mon, 4 Sep 2017 20:27:22 +0000 (-0400)
Subject: Streamlline reduction based on movecount
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=3ac47c84d35b7cdeea50ecbcf3ad0f73fa848668

Streamlline reduction based on movecount

Use MoveCount History only at quiet moves and simply reduce
reduction by one depth instead of increasing moveCount in formula.

STC:
LLR: 2.96 (-2.94,2.94) [0.00,4.00]
Total: 27511 W: 5171 L: 4919 D: 17421

LTC:
LLR: 2.96 (-2.94,2.94) [0.00,4.00]
Total: 92337 W: 12135 L: 11748 D: 68454

Bench: 6351176
---

diff --git a/src/search.cpp b/src/search.cpp
index 7873e7dc..b68c8b78 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -947,13 +947,16 @@ moves_loop: // When in check search starts from here
           &&  moveCount > 1
           && (!captureOrPromotion || moveCountPruning))
       {
-          int mch = std::max(1, moveCount - (ss-1)->moveCount / 16);
-          Depth r = reduction<PvNode>(improving, depth, mch);
+          Depth r = reduction<PvNode>(improving, depth, moveCount);
 
           if (captureOrPromotion)
               r -= r ? ONE_PLY : DEPTH_ZERO;
           else
           {
+              // Decrease reduction if opponent's move count is high
+              if ((ss-1)->moveCount > 15)
+                  r -= ONE_PLY;
+
               // Increase reduction if ttMove is a capture
               if (ttCapture)
                   r += ONE_PLY;