weka.core

Class BinarySparseInstance

java.lang.Object

weka.core.AbstractInstance

weka.core.SparseInstance

weka.core.BinarySparseInstance

All Implemented Interfaces:

Serializable, Copyable, Instance, RevisionHandler

public class BinarySparseInstance
extends SparseInstance

Class for storing a binary-data-only instance as a sparse vector. A sparse instance only requires storage for those attribute values that are non-zero. Since the objective is to reduce storage requirements for datasets with large numbers of default values, this also includes nominal attributes -- the first nominal value (i.e. that which has index 0) will not require explicit storage, so rearrange your nominal attribute value orderings if necessary. Missing values are not supported, and will be treated as 1 (true).

Version:

$Revision: 12472 $

See Also:

Serialized Form

Field Summary

Fields inherited from class weka.core.AbstractInstance

s_numericAfterDecimalPoint

Constructor Summary

Constructors

Constructor and Description
BinarySparseInstance(double weight, double[] attValues) Constructor that generates a sparse instance from the given parameters.
BinarySparseInstance(double weight, int[] indices, int maxNumValues) Constructor that inititalizes instance variable with given values.
BinarySparseInstance(Instance instance) Constructor that generates a sparse instance from the given instance.
BinarySparseInstance(int numAttributes) Constructor of an instance that sets weight to one, all values to 1, and the reference to the dataset to null.
BinarySparseInstance(SparseInstance instance) Constructor that copies the info from the given instance.

Method Summary

Modifier and Type	Method and Description
Object	copy() Produces a shallow copy of this instance.
Instance	copy(double[] values) Copies the instance but fills up its values based on the given array of doubles.
String	getRevision() Returns the revision string.
static void	main(String[] options) Main method for testing this class.
Instance	mergeInstance(Instance inst) Merges this instance with the given instance and returns the result.
void	replaceMissingValues(double[] array) Does nothing, since we don't support missing values.
void	setValue(int attIndex, double value) Sets a specific value in the instance to the given value (internal floating-point format).
void	setValueSparse(int indexOfIndex, double value) Sets a specific value in the instance to the given value (internal floating-point format).
double[]	toDoubleArray() Returns the values of each attribute as an array of doubles.
String	toString() Returns the description of one instance in sparse format.
double	value(int attIndex) Returns an instance's attribute value in internal format.
double	valueSparse(int indexOfIndex) Returns an instance's attribute value in internal format.

Methods inherited from class weka.core.SparseInstance

index, locateIndex, numAttributes, numValues, toStringNoWeight, toStringNoWeight

Methods inherited from class weka.core.AbstractInstance

attribute, attributeSparse, classAttribute, classIndex, classIsMissing, classValue, dataset, deleteAttributeAt, enumerateAttributes, equalHeaders, equalHeadersMsg, hasMissingValue, insertAttributeAt, isMissing, isMissing, isMissingSparse, numClasses, relationalValue, relationalValue, setClassMissing, setClassValue, setClassValue, setDataset, setMissing, setMissing, setValue, setValue, setValue, setWeight, stringValue, stringValue, toString, toString, toString, toString, toStringMaxDecimalDigits, value, weight

Methods inherited from class java.lang.Object

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

Constructor Detail

BinarySparseInstance

public BinarySparseInstance(Instance instance)

Constructor that generates a sparse instance from the given instance. Reference to the dataset is set to null. (ie. the instance doesn't have access to information about the attribute types)

Parameters:

instance - the instance from which the attribute values and the weight are to be copied

BinarySparseInstance

public BinarySparseInstance(SparseInstance instance)

Constructor that copies the info from the given instance. Reference to the dataset is set to null. (ie. the instance doesn't have access to information about the attribute types)

Parameters:

instance - the instance from which the attribute info is to be copied

BinarySparseInstance

public BinarySparseInstance(double weight,
                            double[] attValues)

Constructor that generates a sparse instance from the given parameters. Reference to the dataset is set to null. (ie. the instance doesn't have access to information about the attribute types)

Parameters:

weight - the instance's weight

attValues - a vector of attribute values

BinarySparseInstance

public BinarySparseInstance(double weight,
                            int[] indices,
                            int maxNumValues)

Constructor that inititalizes instance variable with given values. Reference to the dataset is set to null. (ie. the instance doesn't have access to information about the attribute types)

Parameters:

weight - the instance's weight

indices - the indices of the given values in the full vector

maxNumValues - the maximium number of values that can be stored

BinarySparseInstance

public BinarySparseInstance(int numAttributes)

Constructor of an instance that sets weight to one, all values to 1, and the reference to the dataset to null. (ie. the instance doesn't have access to information about the attribute types)

Parameters:

numAttributes - the size of the instance

Method Detail

copy

public Object copy()

Produces a shallow copy of this instance. The copy has access to the same dataset. (if you want to make a copy that doesn't have access to the dataset, use new BinarySparseInstance(instance)

Specified by:

copy in interface Copyable

Overrides:

copy in class SparseInstance

Returns:

the shallow copy

copy

public Instance copy(double[] values)

Copies the instance but fills up its values based on the given array of doubles. The copy has access to the same dataset.

Specified by:

copy in interface Instance

Overrides:

copy in class SparseInstance

Parameters:

values - the array with new values

Returns:

the new instance

mergeInstance

public Instance mergeInstance(Instance inst)

Merges this instance with the given instance and returns the result. Dataset is set to null.

Specified by:

mergeInstance in interface Instance

Overrides:

mergeInstance in class SparseInstance

Parameters:

inst - the instance to be merged with this one

Returns:

the merged instances

replaceMissingValues

public void replaceMissingValues(double[] array)

Does nothing, since we don't support missing values.

Specified by:

replaceMissingValues in interface Instance

Overrides:

replaceMissingValues in class SparseInstance

Parameters:

array - containing the means and modes

setValue

public void setValue(int attIndex,
                     double value)

Sets a specific value in the instance to the given value (internal floating-point format). Performs a deep copy of the vector of attribute values before the value is set.

Specified by:

setValue in interface Instance

Overrides:

setValue in class SparseInstance

Parameters:

attIndex - the attribute's index

value - the new attribute value (If the corresponding attribute is nominal (or a string) then this is the new value's index as a double).

setValueSparse

public void setValueSparse(int indexOfIndex,
                           double value)

Sets a specific value in the instance to the given value (internal floating-point format). Performs a deep copy of the vector of attribute values before the value is set.

Specified by:

setValueSparse in interface Instance

Overrides:

setValueSparse in class SparseInstance

Parameters:

indexOfIndex - the index of the attribute's index

value - the new attribute value (If the corresponding attribute is nominal (or a string) then this is the new value's index as a double).

toDoubleArray

public double[] toDoubleArray()

Returns the values of each attribute as an array of doubles.

Specified by:

toDoubleArray in interface Instance

Overrides:

toDoubleArray in class SparseInstance

Returns:

an array containing all the instance attribute values

toString

public String toString()

Returns the description of one instance in sparse format. If the instance doesn't have access to a dataset, it returns the internal floating-point values. Quotes string values that contain whitespace characters.

Overrides:

toString in class AbstractInstance

Returns:

the instance's description as a string

value

public double value(int attIndex)

Returns an instance's attribute value in internal format.

Specified by:

value in interface Instance

Overrides:

value in class SparseInstance

Parameters:

attIndex - the attribute's index

Returns:

the specified value as a double (If the corresponding attribute is nominal (or a string) then it returns the value's index as a double).

valueSparse

public final double valueSparse(int indexOfIndex)

Returns an instance's attribute value in internal format. Does exactly the same thing as value() if applied to an Instance.

Specified by:

valueSparse in interface Instance

Overrides:

valueSparse in class AbstractInstance

Parameters:

indexOfIndex - the index of the attribute's index

Returns:

the specified value as a double (If the corresponding attribute is nominal (or a string) then it returns the value's index as a double).

main

public static void main(String[] options)

Main method for testing this class.

Parameters:

options - the command line options - ignored

getRevision

public String getRevision()

Returns the revision string.

Specified by:

getRevision in interface RevisionHandler

Overrides:

getRevision in class SparseInstance

Returns:

the revision