From 909e3adede210a124ed9ec4a2f21d73fda61c26d Mon Sep 17 00:00:00 2001 From: Marco Costalba Date: Sat, 10 Apr 2010 10:48:08 +0100 Subject: [PATCH 1/1] Relax TT condition for zugzwang verified null values In this case use a normal VALUE_TYPE_LOWER TT type instead of VALUE_TYPE_NS_LO. This allow us to TT cut-off in a bit more nodes. Signed-off-by: Marco Costalba --- src/search.cpp | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/src/search.cpp b/src/search.cpp index 3f843641..e6ffcb19 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -1388,7 +1388,9 @@ namespace { { assert(value_to_tt(nullValue, ply) == nullValue); - TT.store(posKey, nullValue, VALUE_TYPE_NS_LO, depth, MOVE_NONE); + // Special flag null values that are not zugzwang checked + ValueType vt = (depth < 6 * OnePly ? VALUE_TYPE_NS_LO : VALUE_TYPE_LOWER); + TT.store(posKey, nullValue, vt, depth, MOVE_NONE); return nullValue; } } else { -- 2.39.2