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java.lang.Objectweka.core.Instance
weka.core.SparseInstance
public class SparseInstance
Class for storing an 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 will be stored explicitly.
| Constructor Summary | |
|---|---|
SparseInstance(double weight,
double[] attValues)
Constructor that generates a sparse instance from the given parameters. |
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SparseInstance(double weight,
double[] attValues,
int[] indices,
int maxNumValues)
Constructor that inititalizes instance variable with given values. |
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SparseInstance(Instance instance)
Constructor that generates a sparse instance from the given instance. |
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SparseInstance(int numAttributes)
Constructor of an instance that sets weight to one, all values to be missing, and the reference to the dataset to null. |
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SparseInstance(SparseInstance instance)
Constructor that copies the info from the given instance. |
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| Method Summary | |
|---|---|
Attribute |
attributeSparse(int indexOfIndex)
Returns the attribute associated with the internal index. |
java.lang.Object |
copy()
Produces a shallow copy of this instance. |
java.lang.String |
getRevision()
Returns the revision string. |
int |
index(int position)
Returns the index of the attribute stored at the given position. |
boolean |
isMissing(int attIndex)
Tests if a specific value is "missing". |
int |
locateIndex(int index)
Locates the greatest index that is not greater than the given index. |
static void |
main(java.lang.String[] options)
Main method for testing this class. |
Instance |
mergeInstance(Instance inst)
Merges this instance with the given instance and returns the result. |
int |
numAttributes()
Returns the number of attributes. |
int |
numValues()
Returns the number of values in the sparse vector. |
void |
replaceMissingValues(double[] array)
Replaces all missing values in the instance with the values contained in the given array. |
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. |
java.lang.String |
toString()
Returns the description of one instance in sparse format. |
double |
value(int attIndex)
Returns an instance's attribute value in internal format. |
| Methods inherited from class weka.core.Instance |
|---|
attribute, classAttribute, classIndex, classIsMissing, classValue, dataset, deleteAttributeAt, enumerateAttributes, equalHeaders, hasMissingValue, insertAttributeAt, isMissing, isMissingSparse, isMissingValue, missingValue, numClasses, relationalValue, relationalValue, setClassMissing, setClassValue, setClassValue, setDataset, setMissing, setMissing, setValue, setValue, setValue, setWeight, stringValue, stringValue, toString, toString, value, valueSparse, weight |
| Methods inherited from class java.lang.Object |
|---|
equals, getClass, hashCode, notify, notifyAll, wait, wait, wait |
| Constructor Detail |
|---|
public SparseInstance(Instance instance)
instance - the instance from which the attribute values
and the weight are to be copiedpublic SparseInstance(SparseInstance instance)
instance - the instance from which the attribute
info is to be copied
public SparseInstance(double weight,
double[] attValues)
weight - the instance's weightattValues - a vector of attribute values
public SparseInstance(double weight,
double[] attValues,
int[] indices,
int maxNumValues)
weight - the instance's weightattValues - a vector of attribute values (just the ones to be stored)indices - the indices of the given values in the full vector (need to
be sorted in ascending order)maxNumValues - the maximium number of values that can be storedpublic SparseInstance(int numAttributes)
numAttributes - the size of the instance| Method Detail |
|---|
public Attribute attributeSparse(int indexOfIndex)
attributeSparse in class InstanceindexOfIndex - the index of the attribute's index
UnassignedDatasetException - if instance doesn't have access to a
datasetpublic java.lang.Object copy()
new SparseInstance(instance)
copy in interface Copyablecopy in class Instancepublic int index(int position)
index in class Instanceposition - the position
public boolean isMissing(int attIndex)
isMissing in class InstanceattIndex - the attribute's index
public int locateIndex(int index)
public Instance mergeInstance(Instance inst)
mergeInstance in class Instanceinst - the instance to be merged with this one
public int numAttributes()
numAttributes in class Instancepublic int numValues()
numValues in class Instancepublic void replaceMissingValues(double[] array)
replaceMissingValues in class Instancearray - containing the means and modes
java.lang.IllegalArgumentException - if numbers of attributes are unequal
public void setValue(int attIndex,
double value)
setValue in class InstanceattIndex - the attribute's indexvalue - the new attribute value (If the corresponding
attribute is nominal (or a string) then this is the new value's
index as a double).
public void setValueSparse(int indexOfIndex,
double value)
setValueSparse in class InstanceindexOfIndex - the index of the attribute's indexvalue - the new attribute value (If the corresponding
attribute is nominal (or a string) then this is the new value's
index as a double).public double[] toDoubleArray()
toDoubleArray in class Instancepublic java.lang.String toString()
toString in class Instancepublic double value(int attIndex)
value in class InstanceattIndex - the attribute's index
public static void main(java.lang.String[] options)
public java.lang.String getRevision()
getRevision in interface RevisionHandlergetRevision in class Instance
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