org.apache.spark.ml.clustering

Class GaussianMixture

Object

org.apache.spark.ml.PipelineStage

org.apache.spark.ml.Estimator<GaussianMixtureModel>

org.apache.spark.ml.clustering.GaussianMixture

All Implemented Interfaces:

java.io.Serializable, Logging, Params, DefaultParamsWritable, Identifiable, MLWritable

public class GaussianMixture
extends Estimator<GaussianMixtureModel>
implements DefaultParamsWritable

Gaussian Mixture clustering.

This class performs expectation maximization for multivariate Gaussian Mixture Models (GMMs). A GMM represents a composite distribution of independent Gaussian distributions with associated "mixing" weights specifying each's contribution to the composite.

Given a set of sample points, this class will maximize the log-likelihood for a mixture of k Gaussians, iterating until the log-likelihood changes by less than convergenceTol, or until it has reached the max number of iterations. While this process is generally guaranteed to converge, it is not guaranteed to find a global optimum.

See Also:

Serialized Form

Note:

This algorithm is limited in its number of features since it requires storing a covariance matrix which has size quadratic in the number of features. Even when the number of features does not exceed this limit, this algorithm may perform poorly on high-dimensional data. This is due to high-dimensional data (a) making it difficult to cluster at all (based on statistical/theoretical arguments) and (b) numerical issues with Gaussian distributions.

Constructor Summary

Constructors

Constructor and Description
GaussianMixture()
GaussianMixture(String uid)

Method Summary

Modifier and Type	Method and Description
static Params	clear(Param<?> param)
GaussianMixture	copy(ParamMap extra) Creates a copy of this instance with the same UID and some extra params.
static String	explainParam(Param<?> param)
static String	explainParams()
static ParamMap	extractParamMap()
static ParamMap	extractParamMap(ParamMap extra)
static Param<String>	featuresCol()
GaussianMixtureModel	fit(Dataset<?> dataset) Fits a model to the input data.
static <T> scala.Option<T>	get(Param<T> param)
static <T> scala.Option<T>	getDefault(Param<T> param)
static String	getFeaturesCol()
static int	getK()
int	getK()
static int	getMaxIter()
static <T> T	getOrDefault(Param<T> param)
static Param<Object>	getParam(String paramName)
static String	getPredictionCol()
static String	getProbabilityCol()
static long	getSeed()
static double	getTol()
static <T> boolean	hasDefault(Param<T> param)
static boolean	hasParam(String paramName)
static boolean	isDefined(Param<?> param)
static boolean	isSet(Param<?> param)
static IntParam	k()
IntParam	k() Number of independent Gaussians in the mixture model.
static GaussianMixture	load(String path)
static IntParam	maxIter()
static Param<?>[]	params()
static Param<String>	predictionCol()
static Param<String>	probabilityCol()
static void	save(String path)
static LongParam	seed()
static <T> Params	set(Param<T> param, T value)
GaussianMixture	setFeaturesCol(String value)
GaussianMixture	setK(int value)
GaussianMixture	setMaxIter(int value)
GaussianMixture	setPredictionCol(String value)
GaussianMixture	setProbabilityCol(String value)
GaussianMixture	setSeed(long value)
GaussianMixture	setTol(double value)
static DoubleParam	tol()
static String	toString()
StructType	transformSchema(StructType schema) :: DeveloperApi ::
String	uid() An immutable unique ID for the object and its derivatives.
StructType	validateAndTransformSchema(StructType schema) Validates and transforms the input schema.
static MLWriter	write()

Methods inherited from class org.apache.spark.ml.Estimator

fit, fit, fit, fit

Methods inherited from class Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.apache.spark.ml.param.Params

clear, copyValues, defaultCopy, defaultParamMap, explainParam, explainParams, extractParamMap, extractParamMap, get, getDefault, getOrDefault, getParam, hasDefault, hasParam, isDefined, isSet, paramMap, params, set, set, set, setDefault, setDefault, shouldOwn

Methods inherited from interface org.apache.spark.ml.util.Identifiable

toString

Methods inherited from interface org.apache.spark.ml.util.DefaultParamsWritable

write

Methods inherited from interface org.apache.spark.ml.util.MLWritable

save

Methods inherited from interface org.apache.spark.internal.Logging

initializeLogging, initializeLogIfNecessary, isTraceEnabled, log_, log, logDebug, logDebug, logError, logError, logInfo, logInfo, logName, logTrace, logTrace, logWarning, logWarning

Constructor Detail

GaussianMixture

public GaussianMixture(String uid)

GaussianMixture

public GaussianMixture()

Method Detail

load

public static GaussianMixture load(String path)

toString

public static String toString()

params

public static Param<?>[] params()

explainParam

public static String explainParam(Param<?> param)

explainParams

public static String explainParams()

isSet

public static final boolean isSet(Param<?> param)

isDefined

public static final boolean isDefined(Param<?> param)

hasParam

public static boolean hasParam(String paramName)

getParam

public static Param<Object> getParam(String paramName)

set

public static final <T> Params set(Param<T> param,
                                   T value)

get

public static final <T> scala.Option<T> get(Param<T> param)

clear

public static final Params clear(Param<?> param)

getOrDefault

public static final <T> T getOrDefault(Param<T> param)

getDefault

public static final <T> scala.Option<T> getDefault(Param<T> param)

hasDefault

public static final <T> boolean hasDefault(Param<T> param)

extractParamMap

public static final ParamMap extractParamMap(ParamMap extra)

extractParamMap

public static final ParamMap extractParamMap()

maxIter

public static final IntParam maxIter()

getMaxIter

public static final int getMaxIter()

featuresCol

public static final Param<String> featuresCol()

getFeaturesCol

public static final String getFeaturesCol()

seed

public static final LongParam seed()

getSeed

public static final long getSeed()

predictionCol

public static final Param<String> predictionCol()

getPredictionCol

public static final String getPredictionCol()

probabilityCol

public static final Param<String> probabilityCol()

getProbabilityCol

public static final String getProbabilityCol()

tol

public static final DoubleParam tol()

getTol

public static final double getTol()

k

public static final IntParam k()

getK

public static int getK()

save

public static void save(String path)
                 throws java.io.IOException

Throws:

java.io.IOException

write

public static MLWriter write()

uid

public String uid()

Description copied from interface: Identifiable

An immutable unique ID for the object and its derivatives.

Specified by:

uid in interface Identifiable

Returns:

(undocumented)

copy

public GaussianMixture copy(ParamMap extra)

Description copied from interface: Params

Creates a copy of this instance with the same UID and some extra params. Subclasses should implement this method and set the return type properly. See defaultCopy().

Specified by:

copy in interface Params

Specified by:

copy in class Estimator<GaussianMixtureModel>

Parameters:

extra - (undocumented)

Returns:

(undocumented)

setFeaturesCol

public GaussianMixture setFeaturesCol(String value)

setPredictionCol

public GaussianMixture setPredictionCol(String value)

setProbabilityCol

public GaussianMixture setProbabilityCol(String value)

setK

public GaussianMixture setK(int value)

setMaxIter

public GaussianMixture setMaxIter(int value)

setTol

public GaussianMixture setTol(double value)

setSeed

public GaussianMixture setSeed(long value)

fit

public GaussianMixtureModel fit(Dataset<?> dataset)

Description copied from class: Estimator

Fits a model to the input data.

Specified by:

fit in class Estimator<GaussianMixtureModel>

Parameters:

dataset - (undocumented)

Returns:

(undocumented)

transformSchema

public StructType transformSchema(StructType schema)

Description copied from class: PipelineStage

:: DeveloperApi ::

Check transform validity and derive the output schema from the input schema.

We check validity for interactions between parameters during transformSchema and raise an exception if any parameter value is invalid. Parameter value checks which do not depend on other parameters are handled by Param.validate().

Typical implementation should first conduct verification on schema change and parameter validity, including complex parameter interaction checks.

Specified by:

transformSchema in class PipelineStage

Parameters:

schema - (undocumented)

Returns:

(undocumented)

k

public IntParam k()

Number of independent Gaussians in the mixture model. Must be greater than 1. Default: 2.

Returns:

(undocumented)

getK

public int getK()

validateAndTransformSchema

public StructType validateAndTransformSchema(StructType schema)

Validates and transforms the input schema.

Parameters:

schema - input schema

Returns:

output schema