edu.princeton.cs.algorithms

Class Vector

java.lang.Object

edu.princeton.cs.algorithms.Vector

public class Vector
extends Object

The Vector class represents a d-dimensional mathematical vector. Vectors are immutable: their values cannot be changed after they are created. The class Vectors includes methods for addition, subtraction, dot product, scalar product, unit vector, Euclidean distance, and Euclidean norm.

For additional documentation, see Section 1.2 of Algorithms, 4th Edition by Robert Sedgewick and Kevin Wayne.

Author:

Robert Sedgewick, Kevin Wayne

Constructor Summary

Constructors

Constructor and Description
Vector(double... a) Initializes a vector from either an array or a vararg list.
Vector(int d) Initializes a d-dimensional zero vector.

Method Summary

Methods

Modifier and Type	Method and Description
double	cartesian(int i) Returns the ith cartesian coordinate.
Vector	direction() Returns a unit vector in the direction of this vector.
double	distanceTo(Vector that) Returns the Euclidean distance between this vector and that vector.
double	dot(Vector that) Returns the inner product of this vector with that vector.
int	length() Returns the length of this vector.
double	magnitude() Returns the Euclidean norm of this vector.
static void	main(String[] args) Unit tests the data type methods.
Vector	minus(Vector that) Returns the difference between this vector and that vector: this - that.
Vector	plus(Vector that) Returns the sum of this vector and that vector: this + that.
Vector	times(double factor) Returns the product of this factor multiplied by the scalar factor: this * factor.
String	toString() Returns a string representation of this vector.

Methods inherited from class java.lang.Object

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

Constructor Detail

Vector

public Vector(int d)

Initializes a d-dimensional zero vector.

Parameters:

d - the dimension of the vector

Vector

public Vector(double... a)

Initializes a vector from either an array or a vararg list. The vararg syntax supports a constructor that takes a variable number of arugments such as Vector x = new Vector(1.0, 2.0, 3.0, 4.0).

Parameters:

a - the array or vararg list

Method Detail

length

public int length()

Returns the length of this vector.

Returns:

the dimension of this vector

dot

public double dot(Vector that)

Returns the inner product of this vector with that vector.

Parameters:

that - the other vector

Returns:

the dot product between this vector and that vector

Throws:

IllegalArgumentException - if the lengths of the two vectors are not equal.

magnitude

public double magnitude()

Returns the Euclidean norm of this vector.

Returns:

the Euclidean norm of this vector

distanceTo

public double distanceTo(Vector that)

Returns the Euclidean distance between this vector and that vector.

Parameters:

that - the other vector

Returns:

the Euclidean distance between this vector and that vector

Throws:

IllegalArgumentException - if the lengths of the two vectors are not equal.

plus

public Vector plus(Vector that)

Returns the sum of this vector and that vector: this + that.

Parameters:

that - the vector to add to this vector

Returns:

the sum of this vector and that vector

Throws:

IllegalArgumentException - if the lengths of the two vectors are not equal.

minus

public Vector minus(Vector that)

Returns the difference between this vector and that vector: this - that.

Parameters:

that - the vector to subtract from this vector

Returns:

the difference between this vector and that vector

Throws:

IllegalArgumentException - if the lengths of the two vectors are not equal.

cartesian

public double cartesian(int i)

Returns the ith cartesian coordinate.

Parameters:

i - the coordinate index

Returns:

the ith cartesian coordinate

times

public Vector times(double factor)

Returns the product of this factor multiplied by the scalar factor: this * factor.

Parameters:

factor - the multiplier

Returns:

the scalar product of this vector and factor

direction

public Vector direction()

Returns a unit vector in the direction of this vector.

Returns:

a unit vector in the direction of this vector

Throws:

ArithmeticException - if this vector is the zero vector.

toString

public String toString()

Returns a string representation of this vector.

Overrides:

toString in class Object

Returns:

a string representation of this vector, which consists of the the vector entries, separates by single spaces

main

public static void main(String[] args)

Unit tests the data type methods.