edu.ucla.sspace.vector

Class TernaryVector

java.lang.Object

edu.ucla.sspace.vector.TernaryVector

All Implemented Interfaces:

IntegerVector, SparseVector<Integer>, Vector<Integer>, Serializable

public class TernaryVector
extends Object
implements SparseVector<Integer>, IntegerVector, Serializable

An unmodifiable vector with ternary (+1, 0, -1) values. This class is intended to be lightweight and avoids copying arrays for all operations. Therefore, any changes to such arrays will be reflected in this vector. Any mutating methods will throw an UnsupportedOperationException if called.

Author:

Keith Stevens, David Jurgens

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected int[]	negativeDimensions The indices which are all set to -1.
protected int[]	positiveDimensions The indices which are all set to +1.

Constructor Summary

Constructors

Constructor and Description
TernaryVector(int length, int[] positiveIndices, int[] negativeIndices) Create an TernaryVector with the specified length, and postive and negative dimensions.

Method Summary

Methods

Modifier and Type	Method and Description
int	add(int index, int delta) Throws UnsupportedOperationException if called.
int	get(int index) Returns the value of this vector at the given index.
int[]	getNonZeroIndices() Returns all the indices whose values are non-zero
Integer	getValue(int index) Return the value of the vector at the given index as a Number.
int	length() Return the size of the Vector.
double	magnitude() Returns the magnitude of this vector
int[]	negativeDimensions() Returns the indices at which this vector is valued -1 in sorted order.
int[]	positiveDimensions() Returns the indices at which this vector is valued +1 in sorted order.
void	set(int index, int value) Throws UnsupportedOperationException if called.
void	set(int index, Number value) Throws UnsupportedOperationException if called.
int[]	toArray() Returns an int array representing this vector.

Methods inherited from class java.lang.Object

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

Methods inherited from interface edu.ucla.sspace.vector.Vector

equals, hashCode

Field Detail

positiveDimensions

protected int[] positiveDimensions

The indices which are all set to +1.

negativeDimensions

protected int[] negativeDimensions

The indices which are all set to -1.

Constructor Detail

TernaryVector

public TernaryVector(int length,
             int[] positiveIndices,
             int[] negativeIndices)

Create an TernaryVector with the specified length, and postive and negative dimensions. Note that the provided arrays are not safe. This vector retains references to the arrays and so any modification to their contents will result in a change to this vector.

Parameters:

length - the number of elements in this vector.

positiveIndices - all indices whose values are +1.

negativeIndices - all indices whose values are -1.

Method Detail

add

public int add(int index,
      int delta)

Throws UnsupportedOperationException if called.

Specified by:

add in interface IntegerVector

Parameters:

index - index to change.

delta - the amount to change by.

Returns:

the resulting value at the index

get

public int get(int index)

Returns the value of this vector at the given index..

Specified by:

get in interface IntegerVector

Parameters:

index - index to retrieve.

Returns:

value at index.

getNonZeroIndices

public int[] getNonZeroIndices()

Returns all the indices whose values are non-zero Note that this method is not constant time; this method runs in time proportional the the number of non-zero indices.

Specified by:

getNonZeroIndices in interface SparseVector<Integer>

getValue

public Integer getValue(int index)

Return the value of the vector at the given index as a Number..

Specified by:

getValue in interface IntegerVector

Specified by:

getValue in interface Vector<Integer>

Parameters:

index - index to retrieve.

Returns:

value at index.

length

public int length()

Return the size of the Vector..

Specified by:

length in interface Vector<Integer>

Returns:

size of the vector.

negativeDimensions

public int[] negativeDimensions()

Returns the indices at which this vector is valued -1 in sorted order. Note that the return array is not safe. Any modification to its contents will result in a change to this vector.

Returns:

An array of indices which have negative values.

positiveDimensions

public int[] positiveDimensions()

Returns the indices at which this vector is valued +1 in sorted order. Note that the return array is not safe. Any modification to its contents will result in a change to this vector.

Returns:

An array of indices which have positive values.

magnitude

public double magnitude()

Returns the magnitude of this vector

Specified by:

magnitude in interface Vector<Integer>

set

public void set(int index,
       int value)

Throws UnsupportedOperationException if called.

Specified by:

set in interface IntegerVector

Parameters:

index - index to set.

value - value to set in the vector.

set

public void set(int index,
       Number value)

Throws UnsupportedOperationException if called.

Specified by:

set in interface Vector<Integer>

Parameters:

index - index to set.

value - value to set in the vector.

toArray

public int[] toArray()

Returns an int array representing this vector. The returned array will be "safe" in that no changes to the array will be reflected in the vector, and likewise for changes to to the vector. The caller is thus free to modify the returned array..

Specified by:

toArray in interface IntegerVector

Returns:

an int array of this vector.