Spark ML - Clustering Evaluator

Evaluator for clustering results. The metric computes the Silhouette measure using the squared Euclidean distance. The Silhouette is a measure for the validation of the consistency within clusters. It ranges between 1 and -1, where a value close to 1 means that the points in a cluster are close to the other points in the same cluster and far from the points of the other clusters.

ml_clustering_evaluator(x, features_col = "features",
  prediction_col = "prediction", metric_name = "silhouette",
  uid = random_string("clustering_evaluator_"), ...)

Arguments

x

A spark_connection object or a tbl_spark containing label and prediction columns. The latter should be the output of sdf_predict.

features_col

Name of features column.

prediction_col

Name of the prediction column.

metric_name

The performance metric. Currently supports "silhouette".

uid

A character string used to uniquely identify the ML estimator.

...

Optional arguments; currently unused.

Value

The calculated performance metric

Examples

if (FALSE) { sc <- spark_connect(master = "local") iris_tbl <- sdf_copy_to(sc, iris, name = "iris_tbl", overwrite = TRUE) partitions <- iris_tbl %>% sdf_random_split(training = 0.7, test = 0.3, seed = 1111) iris_training <- partitions$training iris_test <- partitions$test formula <- Species ~ . # Train the models kmeans_model <- ml_kmeans(iris_training, formula = formula) b_kmeans_model <- ml_bisecting_kmeans(iris_training, formula = formula) gmm_model <- ml_gaussian_mixture(iris_training, formula = formula) # Predict pred_kmeans <- ml_predict(kmeans_model, iris_test) pred_b_kmeans <- ml_predict(b_kmeans_model, iris_test) pred_gmm <- ml_predict(gmm_model, iris_test) # Evaluate ml_clustering_evaluator(pred_kmeans) ml_clustering_evaluator(pred_b_kmeans) ml_clustering_evaluator(pred_gmm) }