final class PrefixSpan extends Params
A parallel PrefixSpan algorithm to mine frequent sequential patterns.
The PrefixSpan algorithm is described in J. Pei, et al., PrefixSpan: Mining Sequential Patterns
Efficiently by Prefix-Projected Pattern Growth
(see here).
This class is not yet an Estimator/Transformer, use findFrequentSequentialPatterns
method to
run the PrefixSpan algorithm.
- Annotations
- @Since( "2.4.0" )
- Source
- PrefixSpan.scala
- See also
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Parameters
A list of (hyper-)parameter keys this algorithm can take. Users can set and get the parameter values through setters and getters, respectively.
-
val
maxLocalProjDBSize: LongParam
Param for the maximum number of items (including delimiters used in the internal storage format) allowed in a projected database before local processing (default:
32000000
).Param for the maximum number of items (including delimiters used in the internal storage format) allowed in a projected database before local processing (default:
32000000
). If a projected database exceeds this size, another iteration of distributed prefix growth is run.- Annotations
- @Since( "2.4.0" )
-
val
maxPatternLength: IntParam
Param for the maximal pattern length (default:
10
).Param for the maximal pattern length (default:
10
).- Annotations
- @Since( "2.4.0" )
-
val
minSupport: DoubleParam
Param for the minimal support level (default:
0.1
).Param for the minimal support level (default:
0.1
). Sequential patterns that appear more than (minSupport * size-of-the-dataset) times are identified as frequent sequential patterns.- Annotations
- @Since( "2.4.0" )
-
val
sequenceCol: Param[String]
Param for the name of the sequence column in dataset (default "sequence"), rows with nulls in this column are ignored.
Param for the name of the sequence column in dataset (default "sequence"), rows with nulls in this column are ignored.
- Annotations
- @Since( "2.4.0" )
Members
-
final
def
clear(param: Param[_]): PrefixSpan.this.type
Clears the user-supplied value for the input param.
Clears the user-supplied value for the input param.
- Definition Classes
- Params
-
def
copy(extra: ParamMap): PrefixSpan
Creates a copy of this instance with the same UID and some extra 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()
.- Definition Classes
- PrefixSpan → Params
- Annotations
- @Since( "2.4.0" )
-
def
explainParam(param: Param[_]): String
Explains a param.
Explains a param.
- param
input param, must belong to this instance.
- returns
a string that contains the input param name, doc, and optionally its default value and the user-supplied value
- Definition Classes
- Params
-
def
explainParams(): String
Explains all params of this instance.
Explains all params of this instance. See
explainParam()
.- Definition Classes
- Params
-
final
def
extractParamMap(): ParamMap
extractParamMap
with no extra values.extractParamMap
with no extra values.- Definition Classes
- Params
-
final
def
extractParamMap(extra: ParamMap): ParamMap
Extracts the embedded default param values and user-supplied values, and then merges them with extra values from input into a flat param map, where the latter value is used if there exist conflicts, i.e., with ordering: default param values less than user-supplied values less than extra.
Extracts the embedded default param values and user-supplied values, and then merges them with extra values from input into a flat param map, where the latter value is used if there exist conflicts, i.e., with ordering: default param values less than user-supplied values less than extra.
- Definition Classes
- Params
-
def
findFrequentSequentialPatterns(dataset: Dataset[_]): DataFrame
Finds the complete set of frequent sequential patterns in the input sequences of itemsets.
Finds the complete set of frequent sequential patterns in the input sequences of itemsets.
- dataset
A dataset or a dataframe containing a sequence column which is
ArrayType(ArrayType(T))
- returns
A
DataFrame
that contains columns of sequence and corresponding frequency. The schema of it will be:sequence: ArrayType(ArrayType(T))
(T is the item type)freq: Long
- Annotations
- @Since( "2.4.0" )
-
final
def
get[T](param: Param[T]): Option[T]
Optionally returns the user-supplied value of a param.
Optionally returns the user-supplied value of a param.
- Definition Classes
- Params
-
final
def
getDefault[T](param: Param[T]): Option[T]
Gets the default value of a parameter.
Gets the default value of a parameter.
- Definition Classes
- Params
-
final
def
getOrDefault[T](param: Param[T]): T
Gets the value of a param in the embedded param map or its default value.
Gets the value of a param in the embedded param map or its default value. Throws an exception if neither is set.
- Definition Classes
- Params
-
def
getParam(paramName: String): Param[Any]
Gets a param by its name.
Gets a param by its name.
- Definition Classes
- Params
-
final
def
hasDefault[T](param: Param[T]): Boolean
Tests whether the input param has a default value set.
Tests whether the input param has a default value set.
- Definition Classes
- Params
-
def
hasParam(paramName: String): Boolean
Tests whether this instance contains a param with a given name.
Tests whether this instance contains a param with a given name.
- Definition Classes
- Params
-
final
def
isDefined(param: Param[_]): Boolean
Checks whether a param is explicitly set or has a default value.
Checks whether a param is explicitly set or has a default value.
- Definition Classes
- Params
-
final
def
isSet(param: Param[_]): Boolean
Checks whether a param is explicitly set.
Checks whether a param is explicitly set.
- Definition Classes
- Params
-
lazy val
params: Array[Param[_]]
Returns all params sorted by their names.
Returns all params sorted by their names. The default implementation uses Java reflection to list all public methods that have no arguments and return Param.
- Definition Classes
- Params
- Note
Developer should not use this method in constructor because we cannot guarantee that this variable gets initialized before other params.
-
final
def
set[T](param: Param[T], value: T): PrefixSpan.this.type
Sets a parameter in the embedded param map.
Sets a parameter in the embedded param map.
- Definition Classes
- Params
-
def
toString(): String
- Definition Classes
- Identifiable → AnyRef → Any
-
val
uid: String
An immutable unique ID for the object and its derivatives.
An immutable unique ID for the object and its derivatives.
- Definition Classes
- PrefixSpan → Identifiable
- Annotations
- @Since( "2.4.0" )
Parameter setters
-
def
setMaxLocalProjDBSize(value: Long): PrefixSpan.this.type
- Annotations
- @Since( "2.4.0" )
-
def
setMaxPatternLength(value: Int): PrefixSpan.this.type
- Annotations
- @Since( "2.4.0" )
-
def
setMinSupport(value: Double): PrefixSpan.this.type
- Annotations
- @Since( "2.4.0" )
-
def
setSequenceCol(value: String): PrefixSpan.this.type
- Annotations
- @Since( "2.4.0" )