From 3589bd008a3470336b3587e3a292a4cd6b02bf6b Mon Sep 17 00:00:00 2001 From: Joost VandeVondele Date: Thu, 2 Feb 2023 08:41:32 +0100 Subject: [PATCH] Update WLD model update the WLD model with about 400M positions extracted from recent LTC games after the net updates. This ensures that the 50% win rate is again at 1.0 eval. closes https://github.com/official-stockfish/Stockfish/pull/4373 No functional change. --- src/uci.cpp | 4 ++-- src/uci.h | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-) diff --git a/src/uci.cpp b/src/uci.cpp index 2afd2de7..3883b3d3 100644 --- a/src/uci.cpp +++ b/src/uci.cpp @@ -206,8 +206,8 @@ namespace { // The coefficients of a third-order polynomial fit is based on the fishtest data // for two parameters that need to transform eval to the argument of a logistic // function. - constexpr double as[] = { -0.58270499, 2.68512549, 15.24638015, 344.49745382}; - constexpr double bs[] = { -2.65734562, 15.96509799, -20.69040836, 73.61029937 }; + constexpr double as[] = { 0.33677609, -4.30175627, 33.08810557, 365.60223431}; + constexpr double bs[] = { -2.50471102, 14.23235405, -14.33066859, 71.42705250 }; // Enforce that NormalizeToPawnValue corresponds to a 50% win rate at ply 64 static_assert(UCI::NormalizeToPawnValue == int(as[0] + as[1] + as[2] + as[3])); diff --git a/src/uci.h b/src/uci.h index bd3df323..5d8ccf1a 100644 --- a/src/uci.h +++ b/src/uci.h @@ -35,7 +35,7 @@ namespace UCI { // the win_rate_model() such that Stockfish outputs an advantage of // "100 centipawns" for a position if the engine has a 50% probability to win // from this position in selfplay at fishtest LTC time control. -const int NormalizeToPawnValue = 361; +const int NormalizeToPawnValue = 394; class Option;