From 63ba8d49cdbb15918098267aa639b341b4c8543c Mon Sep 17 00:00:00 2001
From: NiTeFiSe <rssepteos@gmail.com>
Date: Sat, 31 Mar 2018 13:52:01 -0400
Subject: [PATCH] Revert "Enhanced verify search (#1338)"

This reverts commit b53239d6410cfc87bf454370671390b04879ef05.
---
 src/search.cpp | 12 +-----------
 src/thread.cpp |  2 --
 src/thread.h   |  2 +-
 3 files changed, 2 insertions(+), 14 deletions(-)

diff --git a/src/search.cpp b/src/search.cpp
index 1aa3e92e694..17810d65db2 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -681,8 +681,7 @@ namespace {
     // Step 8. Null move search with verification search (is omitted in PV nodes)
     if (   !PvNode
         &&  eval >= beta
-        &&  ss->staticEval >= beta - 36 * depth / ONE_PLY + 225
-		&& (ss->ply >= thisThread->nmp_ply || ss->ply % 2 == thisThread->pair))
+        &&  ss->staticEval >= beta - 36 * depth / ONE_PLY + 225)
     {
 
         assert(eval - beta >= 0);
@@ -708,17 +707,8 @@ namespace {
                 return nullValue;
 
             // Do verification search at high depths
-            R += ONE_PLY;
-            // disable null move pruning for side to move for the first part of the remaining search tree
-            int nmp_ply = thisThread->nmp_ply;
-            int pair = thisThread->pair;
-            thisThread->nmp_ply = ss->ply + 3 * (depth-R) / 4;
-            thisThread->pair = (ss->ply % 2) == 0;
-
             Value v = depth-R < ONE_PLY ? qsearch<NonPV, false>(pos, ss, beta-1, beta)
                                         :  search<NonPV>(pos, ss, beta-1, beta, depth-R, false, true);
-            thisThread->pair = pair;
-            thisThread->nmp_ply = nmp_ply;
 
             if (v >= beta)
                 return nullValue;
diff --git a/src/thread.cpp b/src/thread.cpp
index 58d693cf2a5..3f3f26cd63f 100644
--- a/src/thread.cpp
+++ b/src/thread.cpp
@@ -187,8 +187,6 @@ void ThreadPool::start_thinking(Position& pos, StateListPtr& states,
       th->rootDepth = th->completedDepth = DEPTH_ZERO;
       th->rootMoves = rootMoves;
       th->rootPos.set(pos.fen(), pos.is_chess960(), &setupStates->back(), th);
-      th->nmp_ply = 0;
-      th->pair = -1;
   }
 
   setupStates->back() = tmp;
diff --git a/src/thread.h b/src/thread.h
index e2009a7d78b..1780abe1da8 100644
--- a/src/thread.h
+++ b/src/thread.h
@@ -61,7 +61,7 @@ class Thread {
   Material::Table materialTable;
   Endgames endgames;
   size_t PVIdx;
-  int selDepth, nmp_ply, pair;
+  int selDepth;
   std::atomic<uint64_t> nodes, tbHits;
 
   Position rootPos;