FeatureVector (LBJava 1.2.22 API)

java.lang.Object
- edu.illinois.cs.cogcomp.lbjava.classify.FeatureVector

All Implemented Interfaces:

Serializable, Cloneable
```
public class FeatureVector
extends Object
implements Cloneable, Serializable
```
Objects of this class are returned by classifiers that have been applied to an object.

Author:

Nick Rizzolo

See Also:

Serialized Form

Field Summary

Fields
Modifier and Type	Field and Description
`protected FVector`	`features` Stores non-label features.
`protected FVector`	`labels` Stores labels.
`protected FeatureVector`	`realCache` Caches the result of the `makeReal()` method.
`protected double`	`weight` With this variable, the user can weight the entire vector.

Constructor Summary

Constructors
Constructor and Description
`FeatureVector()` Simply instantiates the member variables.
`FeatureVector(Feature f)` Creates the vector and adds the given feature to it.
`FeatureVector(Feature[] features)` Creates the vector and adds the given features to it.
`FeatureVector(Object[] ex, Lexicon lex, Lexicon llex)` Instantiates a feature vector from example arrays and lexicons.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`addFeature(Feature f)` Adds a feature to the vector.
`void`	`addFeatures(FeatureVector v)` Adds all the features in another vector to this vector.
`void`	`addLabel(Feature l)` Adds a label to the vector.
`void`	`addLabels(FeatureVector v)` Adds all the features in another vector (but not the labels in that vector) to the labels of this vector.
`void`	`clear()` Removes all elements from both `features` and `labels`.
`void`	`clearLabels()` Removes all elements from just the `labels` list.
`Object`	`clone()` Returns a shallow clone of this vector; the vectors are cloned, but their elements aren't.
`String[]`	`discreteValueArray()` Returns all the values of the features in this vector (not labels) arranged in a `String` array.
`double`	`dot(FeatureVector vector)` Take the dot product of two feature vectors.
`static double`	`dot(int[] firstFeatures, double[] firstValues, int[] secondFeatures, double[] secondValues)` Computes the dot product of the 2 argument vectors.
`boolean`	`equals(Object o)` Two `FeatureVector`s are equivalent if they contain the same features and labels, as defined by `Feature` equivalence.
`int`	`featuresSize()` Returns the size of just the `features` list.
`Feature`	`firstFeature()` Returns the first feature in `features`.
`Feature`	`firstLabel()` Returns the first feature in `labels`.
`Feature`	`getFeature(int index)` Returns the feature at the specified index.
`Feature`	`getLabel(int index)` Returns the label at the specified index.
`static SortedMap`	`getSortedMap(int[] features, double[] values)` Returns a sorted map where the key is the feature index and the value is the feature value.
`double`	`getWeight()` Returns the value of `weight`.
`int`	`hashCode()` The hash code for a `FeatureVector` is simply the sum of the hash codes of the features and the labels.
`boolean`	`isLabeled()` Determines whether this vector has any labels.
`double`	`L2NormSquared()` Returns the square of the magnitude of the feature vector.
`static double`	`L2NormSquared(double[] exampleValues)` Returns the square of the magnitude of the given vector.
`int`	`labelsSize()` Returns the size of just the `labels` list.
`FeatureVector`	`makeReal()` Converts all of the features in the `features` list to `RealFeature`s with appropriate strengths.
`void`	`read(edu.illinois.cs.cogcomp.core.datastructures.vectors.ExceptionlessInputStream in)` Reads the binary representation of a feature vector from the specified stream, overwriting the contents of this vector.
`double[]`	`realValueArray()` Returns all the values of the features in this vector (not labels) arranged in a `double` array.
`int`	`size()` The size of this vector is defined as the size of `features` plus the size of `labels`.
`void`	`sort()` Sorts both of the feature lists.
`String`	`toString()` Returns the string representation of this `FeatureVector` as created by `write(StringBuffer)`.
`String`	`toStringNoPackage()` Returns the string representation of this `FeatureVector` like `toString()` except without package names.
`boolean`	`valueEquals(FeatureVector vector)` Two `FeatureVector`s have equal value if they contain the same number of `Feature`s and if the values of those `Feature`s are pair-wise equivalent according to the `Feature.valueEquals(String)` method.
`void`	`write(edu.illinois.cs.cogcomp.core.datastructures.vectors.ExceptionlessOutputStream out)` Writes a binary representation of the feature vector.
`void`	`write(StringBuffer buffer)` Creates a string representation of this `FeatureVector`.
`void`	`write(StringBuffer buffer, boolean packages)` Creates a string representation of this `FeatureVector`.

Methods inherited from class java.lang.Object
finalize, getClass, notify, notifyAll, wait, wait, wait

- Field Detail
  - features
```
protected FVector features
```
    Stores non-label features.
  - labels
```
protected FVector labels
```
    Stores labels.
  - weight
```
protected double weight
```
    With this variable, the user can weight the entire vector.
  - realCache
```
protected FeatureVector realCache
```
    Caches the result of the makeReal() method.
- Constructor Detail
  - FeatureVector
```
public FeatureVector()
```
    Simply instantiates the member variables.
  - FeatureVector
```
public FeatureVector(Feature f)
```
    Creates the vector and adds the given feature to it.
    
    Parameters:
    
    f - A feature to start this vector off with.
  - FeatureVector
```
public FeatureVector(Feature[] features)
```
    Creates the vector and adds the given features to it.
    
    Parameters:
    
    features - A feature array to start this vector off with.
  - FeatureVector
```
public FeatureVector(Object[] ex,
                     Lexicon lex,
                     Lexicon llex)
```
    Instantiates a feature vector from example arrays and lexicons.
    
    Parameters:
    
    ex - The example array.
    
    lex - The feature lexicon.
    
    llex - The label lexicon.
- Method Detail
  - size
```
public int size()
```
    The size of this vector is defined as the size of features plus the size of labels.
    
    Returns:
    
    The size of this vector.
  - featuresSize
```
public int featuresSize()
```
    Returns the size of just the features list.
  - labelsSize
```
public int labelsSize()
```
    Returns the size of just the labels list.
  - getFeature
```
public Feature getFeature(int index)
```
    Returns the feature at the specified index.
    
    Parameters:
    
    index - The index of the requested feature.
    
    Returns:
    
    The feature.
  - getLabel
```
public Feature getLabel(int index)
```
    Returns the label at the specified index.
    
    Parameters:
    
    index - The index of the requested label.
    
    Returns:
    
    The label.
  - getWeight
```
public double getWeight()
```
    Returns the value of weight.
  - clear
```
public void clear()
```
    Removes all elements from both features and labels.
  - clearLabels
```
public void clearLabels()
```
    Removes all elements from just the labels list.
  - sort
```
public void sort()
```
    Sorts both of the feature lists.
  - addFeature
```
public void addFeature(Feature f)
```
    Adds a feature to the vector.
    
    Parameters:
    
    f - The features to be added.
  - addFeatures
```
public void addFeatures(FeatureVector v)
```
    Adds all the features in another vector to this vector.
    
    Parameters:
    
    v - The vector whose features are to be added.
  - addLabel
```
public void addLabel(Feature l)
```
    Adds a label to the vector.
    
    Parameters:
    
    l - The label to be added.
  - addLabels
```
public void addLabels(FeatureVector v)
```
    Adds all the features in another vector (but not the labels in that vector) to the labels of this vector.
    
    Parameters:
    
    v - The vector whose features will become this vector's labels.
  - isLabeled
```
public boolean isLabeled()
```
    Determines whether this vector has any labels.
    
    Returns:
    
    true iff this vector has at least one label.
  - makeReal
```
public FeatureVector makeReal()
```
    Converts all of the features in the features list to RealFeatures with appropriate strengths. Otherwise, the returned feature vector is the same as this one. In particular, the labels list of the returned vector is a shallow clone of this vector's labels list.
    
    Returns:
    
    A new feature vector which is the same as this one, except all features have been converted to RealFeatures.
  - discreteValueArray
```
public String[] discreteValueArray()
```
    Returns all the values of the features in this vector (not labels) arranged in a String array.
    
    Returns:
    
    An array of Strings with all the feature values from this vector, or null if there are any RealFeatures in this vector.
  - realValueArray
```
public double[] realValueArray()
```
    Returns all the values of the features in this vector (not labels) arranged in a double array.
    
    Returns:
    
    An array of doubles with all the feature values from this vector, or null if there are any DiscreteFeatures in this vector.
  - firstFeature
```
public Feature firstFeature()
```
    Returns the first feature in features.
    
    Returns:
    
    The first feature, or null if there aren't any.
  - firstLabel
```
public Feature firstLabel()
```
    Returns the first feature in labels.
    
    Returns:
    
    The first label, or null if there aren't any.
  - L2NormSquared
```
public double L2NormSquared()
```
    Returns the square of the magnitude of the feature vector.
    
    Returns:
    
    The square of the magnitude of the feature vector.
  - L2NormSquared
```
public static double L2NormSquared(double[] exampleValues)
```
    Returns the square of the magnitude of the given vector.
    
    Parameters:
    
    exampleValues - A vector.
    
    Returns:
    
    The square of the magnitude of the given vector.
  - hashCode
```
public int hashCode()
```
    The hash code for a FeatureVector is simply the sum of the hash codes of the features and the labels.
    
    Overrides:
    
    hashCode in class Object
    
    Returns:
    
    The hash code of this vector.
  - equals
```
public boolean equals(Object o)
```
    Two FeatureVectors are equivalent if they contain the same features and labels, as defined by Feature equivalence.
    
    Overrides:
    
    equals in class Object
    
    Parameters:
    
    o - The object to compare with this FeatureVector for equality.
    
    Returns:
    
    True iff o is a FeatureVector equivalent with this vector as defined above.
  - getSortedMap
```
public static SortedMap getSortedMap(int[] features,
                                     double[] values)
```
    Returns a sorted map where the key is the feature index and the value is the feature value. If there are multiple occurrences of the same feature, then the corresponding values are summed up.
    
    Parameters:
    
    features - The feature indices.
    
    values - The feature values.
    
    Returns:
    
    The sorted map.
  - dot
```
public static double dot(int[] firstFeatures,
                         double[] firstValues,
                         int[] secondFeatures,
                         double[] secondValues)
```
    Computes the dot product of the 2 argument vectors.
    
    Parameters:
    
    firstFeatures - The first feature vector's indices.
    
    firstValues - The first feature vector's values.
    
    secondFeatures - The second feature vector's indices.
    
    secondValues - The second feature vector's values.
    
    Returns:
    
    The dot product.
  - dot
```
public double dot(FeatureVector vector)
```
    Take the dot product of two feature vectors.
    
    Parameters:
    
    vector - The feature vector to take the dot product with.
    
    Returns:
    
    The dot product of this feature vector and vector.
  - valueEquals
```
public boolean valueEquals(FeatureVector vector)
```
    Two FeatureVectors have equal value if they contain the same number of Features and if the values of those Features are pair-wise equivalent according to the Feature.valueEquals(String) method.
    
    Parameters:
    
    vector - The vector with which to test equivalence.
    
    Returns:
    
    true iff the two vectors are "value equivalent" as defined above.
  - write
```
public void write(StringBuffer buffer)
```
    Creates a string representation of this FeatureVector. A comma separated list of labels appears first, surrounded by square brackets. Then follows a comma separated list of features.
    
    Parameters:
    
    buffer - The buffer in which to create the representation.
  - write
```
public void write(StringBuffer buffer,
                  boolean packages)
```
    Creates a string representation of this FeatureVector. A comma separated list of labels appears first, surrounded by square brackets. Then follows a comma separated list of features.
    
    Parameters:
    
    buffer - The buffer in which to create the representation.
    
    packages - Whether or not to print package names.
  - toString
```
public String toString()
```
    Returns the string representation of this FeatureVector as created by write(StringBuffer).
    
    Overrides:
    
    toString in class Object
  - toStringNoPackage
```
public String toStringNoPackage()
```
    Returns the string representation of this FeatureVector like toString() except without package names.
  - write
```
public void write(edu.illinois.cs.cogcomp.core.datastructures.vectors.ExceptionlessOutputStream out)
```
    Writes a binary representation of the feature vector.
    
    Parameters:
    
    out - The output stream.
  - read
```
public void read(edu.illinois.cs.cogcomp.core.datastructures.vectors.ExceptionlessInputStream in)
```
    Reads the binary representation of a feature vector from the specified stream, overwriting the contents of this vector.
    
    Parameters:
    
    in - The input stream.
  - clone
```
public Object clone()
```
    Returns a shallow clone of this vector; the vectors are cloned, but their elements aren't.
    
    Overrides:
    
    clone in class Object

Class FeatureVector

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

features

labels

weight

realCache

Constructor Detail

FeatureVector

FeatureVector

FeatureVector

FeatureVector

Method Detail

size

featuresSize

labelsSize

getFeature

getLabel

getWeight

clear

clearLabels

sort

addFeature

addFeatures

addLabel

addLabels

isLabeled

makeReal

discreteValueArray

realValueArray

firstFeature

firstLabel

L2NormSquared

L2NormSquared

hashCode

equals

getSortedMap

dot

dot

valueEquals

write

write

toString

toStringNoPackage

write

read

clone