org.apache.commons.math3.geometry.euclidean.twod
Class Vector2D

java.lang.Object
  extended by org.apache.commons.math3.geometry.euclidean.twod.Vector2D
All Implemented Interfaces:
Serializable, Vector<Euclidean2D>

public class Vector2D
extends Object
implements Vector<Euclidean2D>

This class represents a 2D vector.

Instances of this class are guaranteed to be immutable.

Since:
3.0
Version:
$Id: Vector2D.java 1416643 2012-12-03 19:37:14Z tn $
See Also:
Serialized Form

Field Summary
static Vector2D NaN
          A vector with all coordinates set to NaN.
static Vector2D NEGATIVE_INFINITY
          A vector with all coordinates set to negative infinity.
static Vector2D POSITIVE_INFINITY
          A vector with all coordinates set to positive infinity.
static Vector2D ZERO
          Origin (coordinates: 0, 0).
 
Constructor Summary
Vector2D(double[] v)
          Simple constructor.
Vector2D(double x, double y)
          Simple constructor.
Vector2D(double a, Vector2D u)
          Multiplicative constructor Build a vector from another one and a scale factor.
Vector2D(double a1, Vector2D u1, double a2, Vector2D u2)
          Linear constructor Build a vector from two other ones and corresponding scale factors.
Vector2D(double a1, Vector2D u1, double a2, Vector2D u2, double a3, Vector2D u3)
          Linear constructor Build a vector from three other ones and corresponding scale factors.
Vector2D(double a1, Vector2D u1, double a2, Vector2D u2, double a3, Vector2D u3, double a4, Vector2D u4)
          Linear constructor Build a vector from four other ones and corresponding scale factors.
 
Method Summary
 Vector2D add(double factor, Vector<Euclidean2D> v)
          Add a scaled vector to the instance.
 Vector2D add(Vector<Euclidean2D> v)
          Add a vector to the instance.
 double distance(Vector<Euclidean2D> p)
          Compute the distance between the instance and another vector according to the L2 norm.
static double distance(Vector2D p1, Vector2D p2)
          Compute the distance between two vectors according to the L2 norm.
 double distance1(Vector<Euclidean2D> p)
          Compute the distance between the instance and another vector according to the L1 norm.
 double distanceInf(Vector<Euclidean2D> p)
          Compute the distance between the instance and another vector according to the L norm.
static double distanceInf(Vector2D p1, Vector2D p2)
          Compute the distance between two vectors according to the L norm.
 double distanceSq(Vector<Euclidean2D> p)
          Compute the square of the distance between the instance and another vector.
static double distanceSq(Vector2D p1, Vector2D p2)
          Compute the square of the distance between two vectors.
 double dotProduct(Vector<Euclidean2D> v)
          Compute the dot-product of the instance and another vector.
 boolean equals(Object other)
          Test for the equality of two 2D vectors.
 double getNorm()
          Get the L2 norm for the vector.
 double getNorm1()
          Get the L1 norm for the vector.
 double getNormInf()
          Get the L norm for the vector.
 double getNormSq()
          Get the square of the norm for the vector.
 Space getSpace()
          Get the space to which the vector belongs.
 double getX()
          Get the abscissa of the vector.
 double getY()
          Get the ordinate of the vector.
 Vector2D getZero()
          Get the null vector of the vectorial space or origin point of the affine space.
 int hashCode()
          Get a hashCode for the 2D vector.
 boolean isInfinite()
          Returns true if any coordinate of this vector is infinite and none are NaN; false otherwise
 boolean isNaN()
          Returns true if any coordinate of this vector is NaN; false otherwise
 Vector2D negate()
          Get the opposite of the instance.
 Vector2D normalize()
          Get a normalized vector aligned with the instance.
 Vector2D scalarMultiply(double a)
          Multiply the instance by a scalar.
 Vector2D subtract(double factor, Vector<Euclidean2D> v)
          Subtract a scaled vector from the instance.
 Vector2D subtract(Vector<Euclidean2D> p)
          Subtract a vector from the instance.
 double[] toArray()
          Get the vector coordinates as a dimension 2 array.
 String toString()
          Get a string representation of this vector.
 String toString(NumberFormat format)
          Get a string representation of this vector.
 
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
 

Field Detail

ZERO

public static final Vector2D ZERO
Origin (coordinates: 0, 0).


NaN

public static final Vector2D NaN
A vector with all coordinates set to NaN.


POSITIVE_INFINITY

public static final Vector2D POSITIVE_INFINITY
A vector with all coordinates set to positive infinity.


NEGATIVE_INFINITY

public static final Vector2D NEGATIVE_INFINITY
A vector with all coordinates set to negative infinity.

Constructor Detail

Vector2D

public Vector2D(double x,
                double y)
Simple constructor. Build a vector from its coordinates

Parameters:
x - abscissa
y - ordinate
See Also:
getX(), getY()

Vector2D

public Vector2D(double[] v)
         throws DimensionMismatchException
Simple constructor. Build a vector from its coordinates

Parameters:
v - coordinates array
Throws:
DimensionMismatchException - if array does not have 2 elements
See Also:
toArray()

Vector2D

public Vector2D(double a,
                Vector2D u)
Multiplicative constructor Build a vector from another one and a scale factor. The vector built will be a * u

Parameters:
a - scale factor
u - base (unscaled) vector

Vector2D

public Vector2D(double a1,
                Vector2D u1,
                double a2,
                Vector2D u2)
Linear constructor Build a vector from two other ones and corresponding scale factors. The vector built will be a1 * u1 + a2 * u2

Parameters:
a1 - first scale factor
u1 - first base (unscaled) vector
a2 - second scale factor
u2 - second base (unscaled) vector

Vector2D

public Vector2D(double a1,
                Vector2D u1,
                double a2,
                Vector2D u2,
                double a3,
                Vector2D u3)
Linear constructor Build a vector from three other ones and corresponding scale factors. The vector built will be a1 * u1 + a2 * u2 + a3 * u3

Parameters:
a1 - first scale factor
u1 - first base (unscaled) vector
a2 - second scale factor
u2 - second base (unscaled) vector
a3 - third scale factor
u3 - third base (unscaled) vector

Vector2D

public Vector2D(double a1,
                Vector2D u1,
                double a2,
                Vector2D u2,
                double a3,
                Vector2D u3,
                double a4,
                Vector2D u4)
Linear constructor Build a vector from four other ones and corresponding scale factors. The vector built will be a1 * u1 + a2 * u2 + a3 * u3 + a4 * u4

Parameters:
a1 - first scale factor
u1 - first base (unscaled) vector
a2 - second scale factor
u2 - second base (unscaled) vector
a3 - third scale factor
u3 - third base (unscaled) vector
a4 - fourth scale factor
u4 - fourth base (unscaled) vector
Method Detail

getX

public double getX()
Get the abscissa of the vector.

Returns:
abscissa of the vector
See Also:
Vector2D(double, double)

getY

public double getY()
Get the ordinate of the vector.

Returns:
ordinate of the vector
See Also:
Vector2D(double, double)

toArray

public double[] toArray()
Get the vector coordinates as a dimension 2 array.

Returns:
vector coordinates
See Also:
Vector2D(double[])

getSpace

public Space getSpace()
Get the space to which the vector belongs.

Specified by:
getSpace in interface Vector<Euclidean2D>
Returns:
containing space

getZero

public Vector2D getZero()
Get the null vector of the vectorial space or origin point of the affine space.

Specified by:
getZero in interface Vector<Euclidean2D>
Returns:
null vector of the vectorial space or origin point of the affine space

getNorm1

public double getNorm1()
Get the L1 norm for the vector.

Specified by:
getNorm1 in interface Vector<Euclidean2D>
Returns:
L1 norm for the vector

getNorm

public double getNorm()
Get the L2 norm for the vector.

Specified by:
getNorm in interface Vector<Euclidean2D>
Returns:
Euclidean norm for the vector

getNormSq

public double getNormSq()
Get the square of the norm for the vector.

Specified by:
getNormSq in interface Vector<Euclidean2D>
Returns:
square of the Euclidean norm for the vector

getNormInf

public double getNormInf()
Get the L norm for the vector.

Specified by:
getNormInf in interface Vector<Euclidean2D>
Returns:
L norm for the vector

add

public Vector2D add(Vector<Euclidean2D> v)
Add a vector to the instance.

Specified by:
add in interface Vector<Euclidean2D>
Parameters:
v - vector to add
Returns:
a new vector

add

public Vector2D add(double factor,
                    Vector<Euclidean2D> v)
Add a scaled vector to the instance.

Specified by:
add in interface Vector<Euclidean2D>
Parameters:
factor - scale factor to apply to v before adding it
v - vector to add
Returns:
a new vector

subtract

public Vector2D subtract(Vector<Euclidean2D> p)
Subtract a vector from the instance.

Specified by:
subtract in interface Vector<Euclidean2D>
Parameters:
p - vector to subtract
Returns:
a new vector

subtract

public Vector2D subtract(double factor,
                         Vector<Euclidean2D> v)
Subtract a scaled vector from the instance.

Specified by:
subtract in interface Vector<Euclidean2D>
Parameters:
factor - scale factor to apply to v before subtracting it
v - vector to subtract
Returns:
a new vector

normalize

public Vector2D normalize()
                   throws MathArithmeticException
Get a normalized vector aligned with the instance.

Specified by:
normalize in interface Vector<Euclidean2D>
Returns:
a new normalized vector
Throws:
MathArithmeticException - if the norm is zero

negate

public Vector2D negate()
Get the opposite of the instance.

Specified by:
negate in interface Vector<Euclidean2D>
Returns:
a new vector which is opposite to the instance

scalarMultiply

public Vector2D scalarMultiply(double a)
Multiply the instance by a scalar.

Specified by:
scalarMultiply in interface Vector<Euclidean2D>
Parameters:
a - scalar
Returns:
a new vector

isNaN

public boolean isNaN()
Returns true if any coordinate of this vector is NaN; false otherwise

Specified by:
isNaN in interface Vector<Euclidean2D>
Returns:
true if any coordinate of this vector is NaN; false otherwise

isInfinite

public boolean isInfinite()
Returns true if any coordinate of this vector is infinite and none are NaN; false otherwise

Specified by:
isInfinite in interface Vector<Euclidean2D>
Returns:
true if any coordinate of this vector is infinite and none are NaN; false otherwise

distance1

public double distance1(Vector<Euclidean2D> p)
Compute the distance between the instance and another vector according to the L1 norm.

Calling this method is equivalent to calling: q.subtract(p).getNorm1() except that no intermediate vector is built

Specified by:
distance1 in interface Vector<Euclidean2D>
Parameters:
p - second vector
Returns:
the distance between the instance and p according to the L1 norm

distance

public double distance(Vector<Euclidean2D> p)
Compute the distance between the instance and another vector according to the L2 norm.

Calling this method is equivalent to calling: q.subtract(p).getNorm() except that no intermediate vector is built

Specified by:
distance in interface Vector<Euclidean2D>
Parameters:
p - second vector
Returns:
the distance between the instance and p according to the L2 norm

distanceInf

public double distanceInf(Vector<Euclidean2D> p)
Compute the distance between the instance and another vector according to the L norm.

Calling this method is equivalent to calling: q.subtract(p).getNormInf() except that no intermediate vector is built

Specified by:
distanceInf in interface Vector<Euclidean2D>
Parameters:
p - second vector
Returns:
the distance between the instance and p according to the L norm

distanceSq

public double distanceSq(Vector<Euclidean2D> p)
Compute the square of the distance between the instance and another vector.

Calling this method is equivalent to calling: q.subtract(p).getNormSq() except that no intermediate vector is built

Specified by:
distanceSq in interface Vector<Euclidean2D>
Parameters:
p - second vector
Returns:
the square of the distance between the instance and p

dotProduct

public double dotProduct(Vector<Euclidean2D> v)
Compute the dot-product of the instance and another vector.

Specified by:
dotProduct in interface Vector<Euclidean2D>
Parameters:
v - second vector
Returns:
the dot product this.v

distance

public static double distance(Vector2D p1,
                              Vector2D p2)
Compute the distance between two vectors according to the L2 norm.

Calling this method is equivalent to calling: p1.subtract(p2).getNorm() except that no intermediate vector is built

Parameters:
p1 - first vector
p2 - second vector
Returns:
the distance between p1 and p2 according to the L2 norm

distanceInf

public static double distanceInf(Vector2D p1,
                                 Vector2D p2)
Compute the distance between two vectors according to the L norm.

Calling this method is equivalent to calling: p1.subtract(p2).getNormInf() except that no intermediate vector is built

Parameters:
p1 - first vector
p2 - second vector
Returns:
the distance between p1 and p2 according to the L norm

distanceSq

public static double distanceSq(Vector2D p1,
                                Vector2D p2)
Compute the square of the distance between two vectors.

Calling this method is equivalent to calling: p1.subtract(p2).getNormSq() except that no intermediate vector is built

Parameters:
p1 - first vector
p2 - second vector
Returns:
the square of the distance between p1 and p2

equals

public boolean equals(Object other)
Test for the equality of two 2D vectors.

If all coordinates of two 2D vectors are exactly the same, and none are Double.NaN, the two 2D vectors are considered to be equal.

NaN coordinates are considered to affect globally the vector and be equals to each other - i.e, if either (or all) coordinates of the 2D vector are equal to Double.NaN, the 2D vector is equal to NaN.

Overrides:
equals in class Object
Parameters:
other - Object to test for equality to this
Returns:
true if two 2D vector objects are equal, false if object is null, not an instance of Vector2D, or not equal to this Vector2D instance

hashCode

public int hashCode()
Get a hashCode for the 2D vector.

All NaN values have the same hash code.

Overrides:
hashCode in class Object
Returns:
a hash code value for this object

toString

public String toString()
Get a string representation of this vector.

Overrides:
toString in class Object
Returns:
a string representation of this vector

toString

public String toString(NumberFormat format)
Get a string representation of this vector.

Specified by:
toString in interface Vector<Euclidean2D>
Parameters:
format - the custom format for components
Returns:
a string representation of this vector


Copyright © 2003-2013 The Apache Software Foundation. All Rights Reserved.