From 6a19f5832a0b0f94c6677c4ec6aafc9e1f511baa Mon Sep 17 00:00:00 2001 From: Marco Costalba Date: Wed, 16 Feb 2011 08:56:24 +0100 Subject: [PATCH] Avoid permanent PV entries in TT This patch removes a condition that allows a PV entry to remain in TT across games for an unlimited time. Although this produces a nice ELO boost in the long term it is an artifact that affects tests results bewteen version with and without this feature. So remove now and readd before to release because it actually seems a strong feature. As example a verification tournament against SF 2.0.1 starting around +10 ELO after 4K games sligltly climbed to +21 ELO after 14K games !!! Signed-off-by: Marco Costalba --- src/tt.cpp | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/tt.cpp b/src/tt.cpp index 773f03cc..20ac1608 100644 --- a/src/tt.cpp +++ b/src/tt.cpp @@ -122,7 +122,7 @@ void TranspositionTable::store(const Key posKey, Value v, ValueType t, Depth d, continue; c1 = (replace->generation() == generation ? 2 : 0); - c2 = (tte->generation() == generation || tte->type() == VALUE_TYPE_EXACT ? -2 : 0); + c2 = (tte->generation() == generation ? -2 : 0); c3 = (tte->depth() < replace->depth() ? 1 : 0); if (c1 + c2 + c3 > 0) -- 2.39.2