From: H.G.Muller <hgm@hgm-xboard.(none)>
Date: Sat, 14 Jan 2017 18:00:06 +0000 (+0100)
Subject: Respect minimum LMR depth during hash probing
X-Git-Url: http://winboard.nl/cgi-bin?a=commitdiff_plain;h=72e957c6ab6d090acbbf3d96a79d3a0e0e549494;p=crazywa.git

Respect minimum LMR depth during hash probing

We can add the reduction to the actual search depth to determine up to
which depth a probe result ca be used, but only if the actual depth is
at least the miimumdepth where LMR is allowed.
---

diff --git a/dropper.c b/dropper.c
index 825e6b9..64b0bab 100644
--- a/dropper.c
+++ b/dropper.c
@@ -1088,7 +1088,7 @@ 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)*reduction; // fail highs need to satisfy reduced depth only, so we fake higher depth than actually found
+	    d += (score >= beta & entry->depth >= 3)*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
 	    }