From: Joona Kiiski <joona.kiiski@gmail.com>
Date: Wed, 8 Apr 2009 14:35:36 +0000 (+0300)
Subject: Make futility and razor margins more tunable
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=342ceb1c9124ced53650d6c422a8cfa32e0b12ef

Make futility and razor margins more tunable

Restructure RazorMargins and FutilityMargins arrays so that their
values can be more easily tuned.

Add RazorApprMargins array which replaces razorAtDepthOne concept,
because setting RazorApprMargin very high value at ply one is
same as not razoring there at all.

Comment out setting razoring and futility margins through uci to
avoid errors while tuning.

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

diff --git a/src/search.cpp b/src/search.cpp
index a3077680..a3912603 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -180,14 +180,21 @@ namespace {
 
   // Margins for futility pruning in the quiescence search, and at frontier
   // and near frontier nodes
-  Value FutilityMarginQS;
-  Value FutilityMargins[6] = { Value(0x100), Value(0x200), Value(0x250),
-                               Value(0x2A0), Value(0x340), Value(0x3A0) };
+  const Value FutilityMarginQS = Value(0x80);
+
+                  //remaining depth:  1 ply         1.5 ply       2 ply         2.5 ply       3 ply         3.5 ply
+  const Value FutilityMargins[12] = { Value(0x100), Value(0x120), Value(0x200), Value(0x220), Value(0x250), Value(0x270),
+                  //                  4 ply         4.5 ply       5 ply         5.5 ply       6 ply         6.5 ply
+                                      Value(0x2A0), Value(0x2C0), Value(0x340), Value(0x360), Value(0x3A0), Value(0x3C0)};
 
   // Razoring
-  const bool RazorAtDepthOne = false;
-  Depth RazorDepth;
-  Value RazorMargin;
+  const Depth RazorDepth = 4*OnePly;
+
+              //remaining depth:  1 ply         1.5 ply       2 ply         2.5 ply       3 ply         3.5 ply
+  const Value RazorMargins[6] = { Value(0x180), Value(0x300), Value(0x300), Value(0x3C0), Value(0x3C0), Value(0x3C0) };
+
+               //remaining depth:     1 ply            1.5 ply       2 ply         2.5 ply       3 ply         3.5 ply
+  const Value RazorApprMargins[6] = { Value(0x100000), Value(0x300), Value(0x300), Value(0x300), Value(0x300), Value(0x300) };
 
   // Last seconds noise filtering (LSN)
   bool UseLSNFiltering;
@@ -437,13 +444,13 @@ void think(const Position &pos, bool infinite, bool ponder, int side_to_move,
   UseQSearchFutilityPruning = get_option_value_bool("Futility Pruning (Quiescence Search)");
   UseFutilityPruning = get_option_value_bool("Futility Pruning (Main Search)");
 
-  FutilityMarginQS = value_from_centipawns(get_option_value_int("Futility Margin (Quiescence Search)"));
-  int fmScale = get_option_value_int("Futility Margin Scale Factor (Main Search)");
-  for (int i = 0; i < 6; i++)
-      FutilityMargins[i] = (FutilityMargins[i] * fmScale) / 100;
+  //FutilityMarginQS = value_from_centipawns(get_option_value_int("Futility Margin (Quiescence Search)"));
+  //int fmScale = get_option_value_int("Futility Margin Scale Factor (Main Search)");
+  //for (int i = 0; i < 6; i++)
+  //    FutilityMargins[i] = (FutilityMargins[i] * fmScale) / 100;
 
-  RazorDepth = (get_option_value_int("Maximum Razoring Depth") + 1) * OnePly;
-  RazorMargin = value_from_centipawns(get_option_value_int("Razoring Margin"));
+  //RazorDepth = (get_option_value_int("Maximum Razoring Depth") + 1) * OnePly;
+  //RazorMargin = value_from_centipawns(get_option_value_int("Razoring Margin"));
 
   UseLSNFiltering = get_option_value_bool("LSN filtering");
   LSNTime = get_option_value_int("LSN Time Margin (sec)") * 1000;
@@ -1310,17 +1317,14 @@ namespace {
     }
     // Null move search not allowed, try razoring
     else if (   !value_is_mate(beta)
-             && approximateEval < beta - RazorMargin
              && depth < RazorDepth
-             && (RazorAtDepthOne || depth > OnePly)
+             && approximateEval < beta - RazorApprMargins[int(depth) - 2]
              && ttMove == MOVE_NONE
              && !pos.has_pawn_on_7th(pos.side_to_move()))
     {
         Value v = qsearch(pos, ss, beta-1, beta, Depth(0), ply, threadID);
-        if (   (v < beta - RazorMargin - RazorMargin / 4)
-            || (depth <= 2*OnePly && v < beta - RazorMargin)
-            || (depth <=   OnePly && v < beta - RazorMargin / 2))
-            return v;
+        if (v < beta - RazorMargins[int(depth) - 2])
+          return v;
     }
 
     // Go with internal iterative deepening if we don't have a TT move
@@ -1379,8 +1383,7 @@ namespace {
           {
               if (futilityValue == VALUE_NONE)
                   futilityValue =  evaluate(pos, ei, threadID)
-                                 + FutilityMargins[int(depth)/2 - 1]
-                                 + 32 * (depth & 1);
+                                 + FutilityMargins[int(depth) - 2];
 
               if (futilityValue < beta)
               {
diff --git a/src/ucioption.cpp b/src/ucioption.cpp
index ab76997f..d7b3b5b4 100644
--- a/src/ucioption.cpp
+++ b/src/ucioption.cpp
@@ -128,10 +128,10 @@ namespace {
     o["Selective Plies"] = Option(7, 0, 10);
     o["Futility Pruning (Main Search)"] = Option(true);
     o["Futility Pruning (Quiescence Search)"] = Option(true);
-    o["Futility Margin (Quiescence Search)"] = Option(50, 0, 1000);
-    o["Futility Margin Scale Factor (Main Search)"] = Option(100, 0, 1000);
-    o["Maximum Razoring Depth"] = Option(3, 0, 4);
-    o["Razoring Margin"] = Option(300, 150, 600);
+    //o["Futility Margin (Quiescence Search)"] = Option(50, 0, 1000);
+    //o["Futility Margin Scale Factor (Main Search)"] = Option(100, 0, 1000);
+    //o["Maximum Razoring Depth"] = Option(3, 0, 4);
+    //o["Razoring Margin"] = Option(300, 150, 600);
     o["LSN filtering"] = Option(true);
     o["LSN Time Margin (sec)"] = Option(4, 1, 10);
     o["LSN Value Margin"] = Option(200, 100, 600);