Classification

Example

This example trains models on the sklean digits dataset which is a copy of the test set of the UCI ML hand-written digits datasets. This demonstrates using a table with a single array feature column for classification. You could do something similar with a vector column.


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-- load the sklearn digits dataset
SELECT pgml.load_dataset('digits');

-- view the dataset
SELECT left(image::text, 40) || ',...}', target FROM pgml.digits LIMIT 10;

-- train a simple model to classify the data
SELECT * FROM pgml.train('Handwritten Digits', 'classification', 'pgml.digits', 'target');

-- check out the predictions
SELECT target, pgml.predict('Handwritten Digits', image) AS prediction
FROM pgml.digits 
LIMIT 10;

-- view raw class probabilities
SELECT target, pgml.predict_proba('Handwritten Digits', image) AS prediction
FROM pgml.digits
LIMIT 10;

Algorithms

We currently support classification algorithms from scikit-learn, XGBoost, LightGBM and Catboost.

Gradient Boosting

Algorithm	Reference
`xgboost`	XGBClassifier
`xgboost_random_forest`	XGBRFClassifier
`lightgbm`	LGBMClassifier
`catboost`	CatBoostClassifier

Examples


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SELECT * FROM pgml.train('Handwritten Digits', algorithm => 'xgboost', hyperparams => '{"n_estimators": 10}');
SELECT * FROM pgml.train('Handwritten Digits', algorithm => 'xgboost_random_forest', hyperparams => '{"n_estimators": 10}');
SELECT * FROM pgml.train('Handwritten Digits', algorithm => 'lightgbm', hyperparams => '{"n_estimators": 1}');
SELECT * FROM pgml.train('Handwritten Digits', algorithm => 'catboost', hyperparams => '{"n_estimators": 1}');

Scikit Ensembles

Algorithm	Reference
`ada_boost`	AdaBoostClassifier
`bagging`	BaggingClassifier
`extra_trees`	ExtraTreesClassifier
`gradient_boosting_trees`	GradientBoostingClassifier
`random_forest`	RandomForestClassifier
`hist_gradient_boosting`	HistGradientBoostingClassifier

Examples


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SELECT * FROM pgml.train('Handwritten Digits', algorithm => 'ada_boost');
SELECT * FROM pgml.train('Handwritten Digits', algorithm => 'bagging');
SELECT * FROM pgml.train('Handwritten Digits', algorithm => 'extra_trees', hyperparams => '{"n_estimators": 10}');
SELECT * FROM pgml.train('Handwritten Digits', algorithm => 'gradient_boosting_trees', hyperparams => '{"n_estimators": 10}');
SELECT * FROM pgml.train('Handwritten Digits', algorithm => 'random_forest', hyperparams => '{"n_estimators": 10}');
SELECT * FROM pgml.train('Handwritten Digits', algorithm => 'hist_gradient_boosting', hyperparams => '{"max_iter": 2}');

Support Vector Machines

Algorithm	Reference
`svm`	SVC
`nu_svm`	NuSVC
`linear_svm`	LinearSVC

Examples


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SELECT * FROM pgml.train('Handwritten Digits', algorithm => 'svm');
SELECT * FROM pgml.train('Handwritten Digits', algorithm => 'nu_svm');
SELECT * FROM pgml.train('Handwritten Digits', algorithm => 'linear_svm');

Linear Models

Algorithm	Reference
`linear`	LogisticRegression
`ridge`	RidgeClassifier
`stochastic_gradient_descent`	SGDClassifier
`perceptron`	Perceptron
`passive_aggressive`	PassiveAggressiveClassifier

Examples


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SELECT * FROM pgml.train('Handwritten Digits', algorithm => 'ridge');
SELECT * FROM pgml.train('Handwritten Digits', algorithm => 'stochastic_gradient_descent');
SELECT * FROM pgml.train('Handwritten Digits', algorithm => 'perceptron');
SELECT * FROM pgml.train('Handwritten Digits', algorithm => 'passive_aggressive');

Other

Algorithm	Reference
`gaussian_process`	GaussianProcessClassifier

Examples


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SELECT * FROM pgml.train('Handwritten Digits', algorithm => 'gaussian_process', hyperparams => '{"max_iter_predict": 100, "warm_start": true}');

PostgresML