kate/BadFish
1
0
Fork 0
mirror of https://github.com/sockspls/badfish synced 2025-04-29 16:23:09 +00:00
Code Issues Releases Wiki Activity

Tweak and update the WDL model

Browse source 
This PR updates the internal WDL model, using data from 2.5M games played by SF-dev (3c62ad7).
Note that the normalizing constant has increased from 329 to 368.

Changes to the fitting procedure:

* the value for --materialMin was increased from 10 to 17: including data with less material leads to less accuracy for larger material count values
* the data was filtered to only include single thread LTC games at 60+0.6
* the data was filtered to only include games from master against patches that are (approximatively) within 5 nElo of master

For more information and plots of the model see PR#5309

closes https://github.com/official-stockfish/Stockfish/pull/5309

No functional change
This commit is contained in:
Robert Nurnberg @ elitebook 2024-05-30 09:05:36 +02:00 • committed by Joost VandeVondele
parent 35aff79843
commit a4ea183e78
1 changed files with 6 additions and 6 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

12
src/uci.cpp
View file

@ -382,12 +382,12 @@ WinRateParams win_rate_params(const Position& pos) {
int material = pos.count<PAWN>() + 3 * pos.count<KNIGHT>() + 3 * pos.count<BISHOP>()
+ 5 * pos.count<ROOK>() + 9 * pos.count<QUEEN>();
// The fitted model only uses data for material counts in [10, 78], and is anchored at count 58.
double m = std::clamp(material, 10, 78) / 58.0;
// The fitted model only uses data for material counts in [17, 78], and is anchored at count 58.
double m = std::clamp(material, 17, 78) / 58.0;
// Return a = p_a(material) and b = p_b(material), see github.com/official-stockfish/WDL_model
constexpr double as[] = {-150.77043883, 394.96159472, -321.73403766, 406.15850091};
constexpr double bs[] = {62.33245393, -91.02264855, 45.88486850, 51.63461272};
constexpr double as[] = {-41.25712052, 121.47473115, -124.46958843, 411.84490997};
constexpr double bs[] = {84.92998051, -143.66658718, 80.09988253, 49.80869370};
double a = (((as[0] * m + as[1]) * m + as[2]) * m) + as[3];
double b = (((bs[0] * m + bs[1]) * m + bs[2]) * m) + bs[3];
@ -428,8 +428,8 @@ std::string UCIEngine::format_score(const Score& s) {
// without treatment of mate and similar special scores.
int UCIEngine::to_cp(Value v, const Position& pos) {
// In general, the score can be defined via the the WDL as
// (log(1/L - 1) - log(1/W - 1)) / ((log(1/L - 1) + log(1/W - 1))
// In general, the score can be defined via the WDL as
// (log(1/L - 1) - log(1/W - 1)) / (log(1/L - 1) + log(1/W - 1)).
// Based on our win_rate_model, this simply yields v / a.
auto [a, b] = win_rate_params(pos);