From: H.G.Muller <hgm@hgm-xboard.(none)>
Date: Sat, 14 Jan 2017 18:07:55 +0000 (+0100)
Subject: Make minimum LMR depth a macro, foreasy tuning
X-Git-Url: http://winboard.nl/cgi-bin?a=commitdiff_plain;h=63155fb8438f660ace9dea9cff7470f603e8a658;p=crazywa.git

Make minimum LMR depth a macro, foreasy tuning
---

diff --git a/dropper.c b/dropper.c
index 64b0bab..5f5e3ea 100644
--- a/dropper.c
+++ b/dropper.c
@@ -9,6 +9,8 @@
 #include <stdlib.h>
 #include <string.h>
 
+#define LMR 2
+
 #define ON  1
 #define OFF 0
 #define INVALID 0
@@ -1088,7 +1090,7 @@ if(PATH)printf("%d:%d   Hash Probe %016llx\n",ply,depth,f.hashKey);
 	}
 if(PATH)printf("      Hit, d=%d, checker = %x\n",entry->depth,f.checker);
 	if((entry->flags & H_LOWER || entry->score <= alpha) && (entry->flags & H_UPPER || entry->score >= beta)) { // compatible bound
-	    d += (score >= beta & entry->depth >= 3)*reduction; // fail highs need to satisfy reduced depth only, so we fake higher depth than actually found
+	    d += (score >= beta & entry->depth >= LMR)*reduction; // fail highs need to satisfy reduced depth only, so we fake higher depth than actually found
 	    if(score > alpha && d >= depth || d >= maxDepth) { // sufficient depth
 		ff->depth = d + 1; return entry->score; // depth was sufficient, take hash cutoff
 	    }
@@ -1120,8 +1122,8 @@ if(hashMove && board[hashMove>>8&255] == 0) {char s[100];sprintf(s,"bad hash mov
     if(f.checker != CK_NONE) {
 	depth++, maxDepth++, reduction = originalReduction = 0 /*, killers[ply][2] = -1*/; // extend check evasions
 	if(earlyGen && f.checkDist && maxDepth <= 1) ipMask = SafeIP(&f);
-    } else if(depth > 3) {
-	if(depth - reduction < 3) reduction = depth - 3; // never reduce to below 3 ply
+    } else if(depth > LMR) {
+	if(depth - reduction < LMR) reduction = depth - LMR; // never reduce to below 'LMR' ply
 	depth -= reduction;
     } else reduction = originalReduction = 0;
 if(PATH)printf("%d:%d   {%d,%d} max=%d eval=%d check=%02x,%d,%d\n",ply,depth,alpha,beta,maxDepth,curEval,f.checker,f.checkDir,f.checkDist);