maspack.matrix
Class VectorObject

java.lang.Object
  maspack.matrix.VectorObject

Direct Known Subclasses:

Quaternion, SpatialVector, Vector2d, Vector3d, Vector4d, VectorNd

public abstract class VectorObject

extends java.lang.Object

Base class for vectors. It provides methods which allow one to set and get elements of a vector, to do various non-modifying queries such as finding out its size, computing it's norms, or comparing it with other vectors. There are also methods fo producing a string representation of the vector and for reading its contents from a tokenizer. There is an abstract method setSize for resizing, which can be used unless the vector size is fixed (which can be determined using isFixedSize).

This base class does not publicly support vector operations such as addition or scaling. The reason for that is that subclasses may implement vectors with a specific structure, which could then be compromised by arbitrary operations. For instance, if a subclass of VectorObject implements unit vectors, it would not make sense for that class to allow an add operation.

Of course, it is possible to corrupt any special subclass structure using the set methods provided in this base class, but it was felt that not including such routines would be overly restrictive. It is therefore up to the user to safeguard subclass integrity when using them.

Note that indices for vector elements are zero-based, so that the range of valid indices for a vector of length n is [0, ... , n-1].

Constructor Summary

VectorObject()

Method Summary

double	dot(VectorObject v1) Returns the dot product of this vector and v1.
boolean	epsilonEquals(VectorObject v1, double eps) Returns true if the elements of this vector equal those of vector v1within a prescribed tolerance epsilon.
boolean	equals(java.lang.Object obj) Returns true if this vector and a specified object have the same class type and if all the elements are exactly equal.
boolean	equals(VectorObject v1) Returns true if the elements of this vector exactly equal those of vector v1.
void	get(double[] values) Copies the elements of this vector into an array of doubles.
abstract double	get(int i) Gets a single element of this vector.
void	get(VectorObject v1) Copies the elements of this vector into another vector object.
double	infinityNorm() Returns the infinity norm of this vector.
boolean	isFixedSize() Returns true if this vector is of fixed size.
double	maxElement() Returns the maximum element value.
double	minElement() Returns the minimum element value.
double	norm() Returns the 2 norm of this vector.
double	normSquared() Returns the square of the 2 norm of this vector.
double	oneNorm() Returns the 1 norm of this vector.
void	scan(java.io.StreamTokenizer stok) Sets the contents of this vector to values read from a StreamTokenizer.
void	set(double[] values) Sets the elements of this vector from an array of doubles.
abstract void	set(int i, double value) Sets a single element of this vector.
void	set(VectorObject v) Sets the values of this vector to those of another vector.
void	setSize(int n) Sets the size of this vector.
abstract int	size() Returns the number of elements in this vector.
java.lang.String	toString() Returns a String representation of this vector, using the default format "%g" (see toString(String).
java.lang.String	toString(NumberFormat fmt) Returns a String representation of this vector, in which each element is formated using a C printf style as decribed by the parameter NumberFormat.
java.lang.String	toString(java.lang.String fmtStr) Returns a String representation of this vector, in which each element is formated using a C printf style format string.

Methods inherited from class java.lang.Object

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

Constructor Detail

VectorObject

public VectorObject()

Method Detail

size

public abstract int size()

Returns the number of elements in this vector.

Returns:

number of elements

get

public abstract double get(int i)

Gets a single element of this vector.

Parameters:

i - element index

Returns:

element value

get

public void get(double[] values)

Copies the elements of this vector into an array of doubles.

Parameters:

values - array into which values are copied

get

public void get(VectorObject v1)
         throws ImproperSizeException

Copies the elements of this vector into another vector object.

Parameters:

v1 - vector object into which values are copied

Throws:

ImproperSizeExcept - if the vector objects have different sizes

ImproperSizeException

set

public abstract void set(int i,
                         double value)

Sets a single element of this vector.

Parameters:

i - element index

value - element value

set

public void set(double[] values)

Sets the elements of this vector from an array of doubles.

Parameters:

values - array from which values are copied

set

public void set(VectorObject v)

Sets the values of this vector to those of another vector.

Parameters:

v - vector from which values are copied

Throws:

ImproperSizeException - vectors have different sizes and this vector cannot be resized accordingly

isFixedSize

public boolean isFixedSize()

Returns true if this vector is of fixed size. If this vector is not of fixed size, then it can be resized dynamically, either explicitly using setSize, or implicitly when used as a result for various vector operations.

Returns:

true if this vector is of fixed size

See Also:

setSize(int)

setSize

public void setSize(int n)

Sets the size of this vector. This operation is only supported if isFixedSize returns false.

Parameters:

n - new size

Throws:

java.lang.UnsupportedOperationException - if this operation is not supported

See Also:

isFixedSize()

norm

public double norm()

Returns the 2 norm of this vector. This is the square root of the sum of the squares of the elements.

Returns:

vector 2 norm

normSquared

public double normSquared()

Returns the square of the 2 norm of this vector. This is the sum of the squares of the elements.

Returns:

square of the 2 norm

oneNorm

public double oneNorm()

Returns the 1 norm of this vector. This is the sum of the absolute values of the elements.

Returns:

vector 1 norm

infinityNorm

public double infinityNorm()

Returns the infinity norm of this vector. This is the maximum absolute value over all elements.

Returns:

vector infinity norm

maxElement

public double maxElement()

Returns the maximum element value.

Returns:

maximal element

minElement

public double minElement()

Returns the minimum element value.

Returns:

minimal element

dot

public double dot(VectorObject v1)
           throws ImproperSizeException

Returns the dot product of this vector and v1.

Parameters:

v1 - right-hand vector

Returns:

dot product

Throws:

ImproperSizeException - if this vector and v1 have different sizes

epsilonEquals

public boolean epsilonEquals(VectorObject v1,
                             double eps)
                      throws ImproperSizeException

Returns true if the elements of this vector equal those of vector v1within a prescribed tolerance epsilon.

Parameters:

v1 - vector to compare with

eps - comparison tolerance

Returns:

false if the vectors are not equal within the specified tolerance, or have different sizes

Throws:

ImproperSizeException

equals

public boolean equals(VectorObject v1)
               throws ImproperSizeException

Returns true if the elements of this vector exactly equal those of vector v1.

Parameters:

v1 - vector to compare with

Returns:

false if the vectors are not equal or have different sizes

Throws:

ImproperSizeException

equals

public boolean equals(java.lang.Object obj)

Returns true if this vector and a specified object have the same class type and if all the elements are exactly equal.

Parameters:

obj - object to compare with

Returns:

false if the objects are not equal

toString

public java.lang.String toString()

Returns a String representation of this vector, using the default format "%g" (see toString(String).

Returns:

String representation of this vector

toString

public java.lang.String toString(java.lang.String fmtStr)

Returns a String representation of this vector, in which each element is formated using a C printf style format string. For a description of the format string syntax, see NumberFormat.

Parameters:

fmtStr - numeric format specification

Returns:

String representation of this vector

toString

public java.lang.String toString(NumberFormat fmt)

Returns a String representation of this vector, in which each element is formated using a C printf style as decribed by the parameter NumberFormat. When called numerous times, this routine can be more efficient than toString(String), because the NumberFormat does not need to be recreated each time from a specification string.

Parameters:

fmt - numeric format

Returns:

String representation of this vector

scan

public void scan(java.io.StreamTokenizer stok)
          throws java.io.IOException

Sets the contents of this vector to values read from a StreamTokenizer. The vector elements should be separated by white space, and the entire set of elements should be surrounded by square brackets. For example,

 [ 1.2 4 5 3.1 ]
 

defines a vector of size 4.

If the vector is not of fixed-size, it will be resized to fit the input. The StreamTokenizer will be set by this method to parse numbers, and it should already be configured to recognize the characters '+' and - as tokens.

Note:This method disables numeric parsing in the StreamTokenizer. This is because the method does its own numeric parsing, in order to handle exponents.

Parameters:

stok - Tokenizer from which vector values are read

Throws:

ImproperSizeException - if this vector has a fixed size which is incompatible with the input

java.io.IOException