pascalabcnet/InstallerSamples/MachineLearning/05_Validation/04_GridSearch_KNN.pas
Mikhalkovich Stanislav 7eaddd9a54 ML - множество примеров
ML - устранение неточностей и багов
ML - оптимизация производительности DecisionTreeRegressor.Fit, RandomForestRegressor.Fit
ML - тесты
2026-05-07 22:53:13 +03:00

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// В этом примере подбирается число соседей k
// для KNNClassifier с помощью GridSearch.
uses MLABC;
begin
var (X, y) := Datasets.MakeMoons(
n := 400,
noise := 0.18,
seed := 42
);
var scaler := new StandardScaler;
scaler.Fit(X);
X := scaler.Transform(X);
var kValues := [1, 3, 5, 7, 9, 11, 15];
Println('Подбор параметра k для KNNClassifier');
Println;
Println('Проверяемые значения k:');
foreach var k in kValues do
begin
var score := Validation.StratifiedCrossValidate(
new KNNClassifier(k, KNNWeighting.Distance),
X, y,
5,
ClassificationMetrics.Accuracy,
seed := 42
);
Println($' k = {k,2} -> средняя Accuracy = {score:F3}');
end;
var (bestK, bestScore, bestModel) := GridSearch.Search(
k -> new KNNClassifier(k, KNNWeighting.Distance),
kValues,
X, y,
5,
ClassificationMetrics.Accuracy,
maximize := True,
stratified := True,
seed := 42
);
Println;
Println($'Лучшее значение k: {bestK}');
Println($'Лучшая средняя Accuracy: {bestScore:F3}');
end.