Package org.djunits.vecmat.d2

Class Vector2<Q extends Quantity<Q,U>,U extends UnitInterface<U,Q>,V extends Vector2<Q,U,V,SI,H>,SI extends Vector2<SIQuantity,SIUnit,SI,?,?>,H extends Vector2<?,?,?,?,?>>

java.lang.Object

org.djunits.vecmat.def.VectorMatrix<Q,U,M,SI,H>

org.djunits.vecmat.def.Matrix<Q,U,V,SI,H>

org.djunits.vecmat.def.Vector<Q,U,V,SI,H>

org.djunits.vecmat.d2.Vector2<Q,U,V,SI,H>

Type Parameters:

Q - the quantity type

U - the unit type

V - the vector type (Row or Col)

SI - the vector type with generics <SIQuantity, SIUnit<

H - the generic vector type with generics <?, ?< for Hadamard operations

All Implemented Interfaces:

Serializable, Iterable<Q>, Additive<V>, Scalable<V>, Value<U,V>, Hadamard<H,SI>, Normed<Q,U>

Direct Known Subclasses:

Vector2.Col, Vector2.Row

public abstract class Vector2<Q extends Quantity<Q,U>,U extends UnitInterface<U,Q>,V extends Vector2<Q,U,V,SI,H>,SI extends Vector2<SIQuantity,SIUnit,SI,?,?>,H extends Vector2<?,?,?,?,?>>
extends Vector<Q,U,V,SI,H>

Vector2 implements a vector with two real-valued entries. The vector is immutable, except for the display unit, which can be changed. Many of the method that have been defined already for a generic vector have been re-implemented for efficiency.

Copyright (c) 2025-2026 Delft University of Technology, Jaffalaan 5, 2628 BX Delft, the Netherlands. All rights reserved. See for project information https://djunits.org. The DJUNITS project is distributed under a three-clause BSD-style license.

Author:

Alexander Verbraeck

See Also:

• Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	Vector2.Col<Q extends Quantity<Q,U>,U extends UnitInterface<U,Q>>	Vector2.Col implements a column vector with two real-valued entries.
static class	Vector2.Row<Q extends Quantity<Q,U>,U extends UnitInterface<U,Q>>	Vector2.Row implements a row vector with two real-valued entries.

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	Vector2(double xInUnit, double yInUnit, U displayUnit)	Create a new Vector2 with a unit.

Method Summary

Modifier and Type	Method	Description
V	abs()	Make the SI-values of this element absolute.
V	add(Q increment)	Return the a vector or matrix with entries that contain the sum of the element and the increment.
V	add(V other)	Add an element to this element, based on the SI-values.
boolean	equals(Object obj)
Q[]	getScalarArray()	Return the vector as an array of scalars.
int	hashCode()
V	instantiateSi(double[] siNew)	Return a new vector or matrix with the given SI or BASE values.
protected abstract V	instantiateSi(double xSiNew, double ySiNew)	Return a column or row vector with x and y values in SI or BASE units.
abstract boolean	isColumnVector()	Return whether this vector is a column vector.
boolean	isRelative()	Indicate whether this is a Relative Value.
Iterator<Q>	iterator()	Create and return an iterator over the scalars in this vector in proper sequence.
Q	max()	Return the maximum value of the elements of the vector or matrix.
Q	mean()	Return the mean value of the elements of the vector or matrix.
Q	median()	Return the median value of the elements of the vector or matrix.
Q	min()	Return the minimum value of the elements of the vector or matrix.
Q	mode()	Return the largest value of the elements of the vector or matrix.
V	negate()	Negate this element, based on the SI-values.
Q	normL1()	Return the L1-norm of this element, expressed as a quantity.
Q	normL2()	Return the L2-norm of this element, expressed as a quantity.
Q	normLinf()	Return the L∞-norm of this element, expressed as a quantity.
Q	normLp(int p)	Return the Lp-norm of this element, expressed as a quantity.
V	scaleBy(double factor)	Scale the element by a dimensionless factor, based on the SI-values.
double[]	si()	Return the contents of the vector as an array.
double	si(int index)	Retrieve an si-value from the vector.
int	size()	Retrieve the size of the vector.
V	subtract(Q decrement)	Return the a vector or matrix with entries that contain the value minus the decrement.
V	subtract(V other)	Subtract an element from this element, based on the SI-values.
Q	sum()	Return the sum of the values of the elements of the vector or matrix.
String	toString()	Return a concise description of this value.
String	toString(U withUnit)	Return a concise description of this value with the values expressed in the specified unit.
Q	x()	Return the x-value of the vector as a quantity with the correct unit.
double	xSi()	Return the x-value of the vector in SI or BASE units.
Q	y()	Return the y-value of the vector as a quantity with the correct unit.
double	ySi()	Return the y-value of the vector in SI or BASE units.

Methods inherited from class org.djunits.vecmat.def.Vector

get, mget, msi

Methods inherited from class org.djunits.vecmat.def.Matrix

checkMultiply, checkMultiply, multiply

Methods inherited from class org.djunits.vecmat.def.VectorMatrix

asMatrixNxM, asQuantityTable, checkCol, checkRow, cols, divideElements, divideElements, get, getColumnScalars, getColumnSi, getColumnVector, getDisplayUnit, getRowScalars, getRowSi, getRowVector, getScalarGrid, instantiateSi, invertElements, mcheckCol, mcheckRow, mget, mgetColumnScalars, mgetColumnSi, mgetColumnVector, mgetRowScalars, mgetRowSi, mgetRowVector, msi, multiplyElements, multiplyElements, multiplyElements, rows, setDisplayUnit, si

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.djunits.vecmat.operations.Hadamard

divideElements

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Methods inherited from interface org.djunits.vecmat.operations.Normed

norm

Methods inherited from interface org.djunits.value.Scalable

divideBy

Methods inherited from interface org.djunits.value.Value

isAbsolute, setDisplayUnit

Constructor Details

Vector2

protected Vector2(double xInUnit,
 double yInUnit,
 U displayUnit)

Create a new Vector2 with a unit.

Parameters:

xInUnit - the x-value expressed in the given unit

yInUnit - the y-value expressed in the given unit

displayUnit - the display unit to use

Method Details

instantiateSi

protected abstract V instantiateSi(double xSiNew,
 double ySiNew)

Return a column or row vector with x and y values in SI or BASE units.

Parameters:

xSiNew - the x value in SI or BASE units

ySiNew - the y value in SI or BASE units

Returns:

a new column or row vector with adapted x and y values

size

public int size()

Description copied from class: Vector

Retrieve the size of the vector.

Specified by:

size in class Vector<Q extends Quantity<Q,U>,U extends UnitInterface<U,Q>,V extends Vector2<Q,U,V,SI,H>,SI extends Vector2<SIQuantity,SIUnit,SI,?,?>,H extends Vector2<?,?,?,?,?>>

Returns:

the size of the vector

si

public double si(int index)
          throws IndexOutOfBoundsException

Description copied from class: Vector

Retrieve an si-value from the vector.

Specified by:

si in class Vector<Q extends Quantity<Q,U>,U extends UnitInterface<U,Q>,V extends Vector2<Q,U,V,SI,H>,SI extends Vector2<SIQuantity,SIUnit,SI,?,?>,H extends Vector2<?,?,?,?,?>>

Parameters:

index - the index (0-based) to retrieve the value from

Returns:

the value as a Scalar

Throws:

IndexOutOfBoundsException - in case index is out of bounds

iterator

public Iterator<Q> iterator()

Description copied from class: Vector

Create and return an iterator over the scalars in this vector in proper sequence.

Specified by:

iterator in interface Iterable<Q extends Quantity<Q,U>>

Specified by:

iterator in class Vector<Q extends Quantity<Q,U>,U extends UnitInterface<U,Q>,V extends Vector2<Q,U,V,SI,H>,SI extends Vector2<SIQuantity,SIUnit,SI,?,?>,H extends Vector2<?,?,?,?,?>>

Returns:

an iterator over the scalars in this vector in proper sequence

getScalarArray

public Q[] getScalarArray()

Description copied from class: Vector

Return the vector as an array of scalars.

Specified by:

getScalarArray in class Vector<Q extends Quantity<Q,U>,U extends UnitInterface<U,Q>,V extends Vector2<Q,U,V,SI,H>,SI extends Vector2<SIQuantity,SIUnit,SI,?,?>,H extends Vector2<?,?,?,?,?>>

Returns:

the vector as an array of scalars

instantiateSi

public V instantiateSi(double[] siNew)

Description copied from class: VectorMatrix

Return a new vector or matrix with the given SI or BASE values.

Specified by:

instantiateSi in class VectorMatrix<Q extends Quantity<Q,U>,U extends UnitInterface<U,Q>,V extends Vector2<Q,U,V,SI,H>,SI extends Vector2<SIQuantity,SIUnit,SI,?,?>,H extends Vector2<?,?,?,?,?>>

Parameters:

siNew - the values for the new vector or matrix in row-major format

Returns:

a new matrix with the provided SI or BASE values

xSi

public double xSi()

Return the x-value of the vector in SI or BASE units.

Returns:

the x-value of the vector in SI or BASE units

ySi

public double ySi()

Return the y-value of the vector in SI or BASE units.

Returns:

the y-value of the vector in SI or BASE units

si

public double[] si()

Return the contents of the vector as an array.

Specified by:

si in class VectorMatrix<Q extends Quantity<Q,U>,U extends UnitInterface<U,Q>,V extends Vector2<Q,U,V,SI,H>,SI extends Vector2<SIQuantity,SIUnit,SI,?,?>,H extends Vector2<?,?,?,?,?>>

Returns:

the contents of the vector as an array

x

public Q x()

Return the x-value of the vector as a quantity with the correct unit.

Returns:

the x-value of the vector as a quantity with the correct unit

y

public Q y()

Return the y-value of the vector as a quantity with the correct unit.

Returns:

the y-value of the vector as a quantity with the correct unit

scaleBy

public V scaleBy(double factor)

Description copied from interface: Scalable

Scale the element by a dimensionless factor, based on the SI-values. Note that this can lead to unwanted effects for elements with Offset scales. 2 * 10 °C = 293.15 °C and not 20 °C.

Specified by:

scaleBy in interface Scalable<Q extends Quantity<Q,U>>

Overrides:

scaleBy in class VectorMatrix<Q extends Quantity<Q,U>,U extends UnitInterface<U,Q>,V extends Vector2<Q,U,V,SI,H>,SI extends Vector2<SIQuantity,SIUnit,SI,?,?>,H extends Vector2<?,?,?,?,?>>

Parameters:

factor - the dimensionless scale factor

Returns:

a new element with all of its SI-values scaled by the dimensionless factor

add

public V add(V other)

Description copied from interface: Additive

Add an element to this element, based on the SI-values. Note that this can lead to unwanted effects for elements with Offset scales: 10 °C + 5 °C = 288.15 °C and not 15 °C.

Specified by:

add in interface Additive<Q extends Quantity<Q,U>>

Overrides:

add in class VectorMatrix<Q extends Quantity<Q,U>,U extends UnitInterface<U,Q>,V extends Vector2<Q,U,V,SI,H>,SI extends Vector2<SIQuantity,SIUnit,SI,?,?>,H extends Vector2<?,?,?,?,?>>

Parameters:

other - the element to add to this element

Returns:

the sum of the SI-values of this element and the SI-values of the other element

subtract

public V subtract(V other)

Description copied from interface: Additive

Subtract an element from this element, based on the SI-values.

Specified by:

subtract in interface Additive<Q extends Quantity<Q,U>>

Overrides:

subtract in class VectorMatrix<Q extends Quantity<Q,U>,U extends UnitInterface<U,Q>,V extends Vector2<Q,U,V,SI,H>,SI extends Vector2<SIQuantity,SIUnit,SI,?,?>,H extends Vector2<?,?,?,?,?>>

Parameters:

other - the element to subtract from this element

Returns:

a new element with the SI-values of this element minus the SI-values of the other element

negate

public V negate()

Description copied from interface: Additive

Negate this element, based on the SI-values. Note that this can lead to unwanted effects for elements with Offset scales. A temperature in Celsius that is negated, will have its Kelvin temperatures negated.

Specified by:

negate in interface Additive<Q extends Quantity<Q,U>>

Overrides:

negate in class VectorMatrix<Q extends Quantity<Q,U>,U extends UnitInterface<U,Q>,V extends Vector2<Q,U,V,SI,H>,SI extends Vector2<SIQuantity,SIUnit,SI,?,?>,H extends Vector2<?,?,?,?,?>>

Returns:

a new element with all of its SI-values negated

abs

public V abs()

Description copied from interface: Additive

Make the SI-values of this element absolute. A new element wil be returned. Note that this can lead to unwanted effects for elements with Offset scales. A temperature of -10 degrees Celsius will have its Kelvin temperatures negated.

Specified by:

abs in interface Additive<Q extends Quantity<Q,U>>

Overrides:

abs in class VectorMatrix<Q extends Quantity<Q,U>,U extends UnitInterface<U,Q>,V extends Vector2<Q,U,V,SI,H>,SI extends Vector2<SIQuantity,SIUnit,SI,?,?>,H extends Vector2<?,?,?,?,?>>

Returns:

a new element with the absolute value for all of its SI-values

normL1

public Q normL1()

Description copied from interface: Normed

Return the L1-norm of this element, expressed as a quantity. The L1-norm is |x1| + |x2| + ... + |xn|.

Returns:

the L1-norm of this element, expressed as a quantity

normL2

public Q normL2()

Description copied from interface: Normed

Return the L2-norm of this element, expressed as a quantity. The L2-norm is sqrt(x1^2 + x2^2 + ... + xn^2).

Returns:

the L2-norm of this element, expressed as a quantity

normLp

public Q normLp(int p)

Description copied from interface: Normed

Return the Lp-norm of this element, expressed as a quantity. The Ln-norm is (x1^p + x2^p + ... + xn^p)^(1/p).

Parameters:

p - the rank of the norm

Returns:

the Lp-norm of this element, expressed as a quantity

normLinf

public Q normLinf()

Description copied from interface: Normed

Return the L∞-norm of this element, expressed as a quantity. The L∞-norm is max(|x1|, |x2|, ..., |xn|).

Returns:

the L∞-norm of this element, expressed as a quantity

mean

public Q mean()

Description copied from class: VectorMatrix

Return the mean value of the elements of the vector or matrix.

Overrides:

mean in class VectorMatrix<Q extends Quantity<Q,U>,U extends UnitInterface<U,Q>,V extends Vector2<Q,U,V,SI,H>,SI extends Vector2<SIQuantity,SIUnit,SI,?,?>,H extends Vector2<?,?,?,?,?>>

Returns:

the mean value of the elements of the vector or matrix

min

public Q min()

Description copied from class: VectorMatrix

Return the minimum value of the elements of the vector or matrix.

Overrides:

min in class VectorMatrix<Q extends Quantity<Q,U>,U extends UnitInterface<U,Q>,V extends Vector2<Q,U,V,SI,H>,SI extends Vector2<SIQuantity,SIUnit,SI,?,?>,H extends Vector2<?,?,?,?,?>>

Returns:

the minimum value of the elements of the vector or matrix

max

public Q max()

Description copied from class: VectorMatrix

Return the maximum value of the elements of the vector or matrix.

Overrides:

max in class VectorMatrix<Q extends Quantity<Q,U>,U extends UnitInterface<U,Q>,V extends Vector2<Q,U,V,SI,H>,SI extends Vector2<SIQuantity,SIUnit,SI,?,?>,H extends Vector2<?,?,?,?,?>>

Returns:

the maximum value of the elements of the vector or matrix

mode

public Q mode()

Description copied from class: VectorMatrix

Return the largest value of the elements of the vector or matrix.

Overrides:

mode in class VectorMatrix<Q extends Quantity<Q,U>,U extends UnitInterface<U,Q>,V extends Vector2<Q,U,V,SI,H>,SI extends Vector2<SIQuantity,SIUnit,SI,?,?>,H extends Vector2<?,?,?,?,?>>

Returns:

the largest value of the elements of the vector or matrix

median

public Q median()

Description copied from class: VectorMatrix

Return the median value of the elements of the vector or matrix.

Overrides:

median in class VectorMatrix<Q extends Quantity<Q,U>,U extends UnitInterface<U,Q>,V extends Vector2<Q,U,V,SI,H>,SI extends Vector2<SIQuantity,SIUnit,SI,?,?>,H extends Vector2<?,?,?,?,?>>

Returns:

the median value of the elements of the vector or matrix

sum

public Q sum()

Description copied from class: VectorMatrix

Return the sum of the values of the elements of the vector or matrix.

Overrides:

sum in class VectorMatrix<Q extends Quantity<Q,U>,U extends UnitInterface<U,Q>,V extends Vector2<Q,U,V,SI,H>,SI extends Vector2<SIQuantity,SIUnit,SI,?,?>,H extends Vector2<?,?,?,?,?>>

Returns:

the sum of the values of the elements of the vector or matrix

add

public V add(Q increment)

Description copied from class: VectorMatrix

Return the a vector or matrix with entries that contain the sum of the element and the increment.

Overrides:

add in class VectorMatrix<Q extends Quantity<Q,U>,U extends UnitInterface<U,Q>,V extends Vector2<Q,U,V,SI,H>,SI extends Vector2<SIQuantity,SIUnit,SI,?,?>,H extends Vector2<?,?,?,?,?>>

Parameters:

increment - the quantity by which to increase the values of the vector or matrix

Returns:

a vector or matrix with elements that are incremented by the given quantity

subtract

public V subtract(Q decrement)

Description copied from class: VectorMatrix

Return the a vector or matrix with entries that contain the value minus the decrement.

Overrides:

subtract in class VectorMatrix<Q extends Quantity<Q,U>,U extends UnitInterface<U,Q>,V extends Vector2<Q,U,V,SI,H>,SI extends Vector2<SIQuantity,SIUnit,SI,?,?>,H extends Vector2<?,?,?,?,?>>

Parameters:

decrement - the quantity by which to decrease the values of the vector or matrix

Returns:

a vector or matrix with elements that are decremented by the given quantity

isRelative

public boolean isRelative()

Description copied from interface: Value

Indicate whether this is a Relative Value.

Specified by:

isRelative in interface Value<Q extends Quantity<Q,U>,U extends UnitInterface<U,Q>>

Overrides:

isRelative in class VectorMatrix<Q extends Quantity<Q,U>,U extends UnitInterface<U,Q>,V extends Vector2<Q,U,V,SI,H>,SI extends Vector2<SIQuantity,SIUnit,SI,?,?>,H extends Vector2<?,?,?,?,?>>

Returns:

whether this is a Relative Value

isColumnVector

public abstract boolean isColumnVector()

Return whether this vector is a column vector.

Specified by:

isColumnVector in class Vector<Q extends Quantity<Q,U>,U extends UnitInterface<U,Q>,V extends Vector2<Q,U,V,SI,H>,SI extends Vector2<SIQuantity,SIUnit,SI,?,?>,H extends Vector2<?,?,?,?,?>>

Returns:

whether this vector is a column vector

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

toString

public String toString(U withUnit)

Description copied from interface: Value

Return a concise description of this value with the values expressed in the specified unit.

Specified by:

toString in interface Value<Q extends Quantity<Q,U>,U extends UnitInterface<U,Q>>

Overrides:

toString in class VectorMatrix<Q extends Quantity<Q,U>,U extends UnitInterface<U,Q>,V extends Vector2<Q,U,V,SI,H>,SI extends Vector2<SIQuantity,SIUnit,SI,?,?>,H extends Vector2<?,?,?,?,?>>

Parameters:

withUnit - the unit into which the values are converted for display

Returns:

a String with the value contents expressed in the specified unit

toString

public String toString()

Description copied from interface: Value

Return a concise description of this value.

Specified by:

toString in interface Value<Q extends Quantity<Q,U>,U extends UnitInterface<U,Q>>

Overrides:

toString in class VectorMatrix<Q extends Quantity<Q,U>,U extends UnitInterface<U,Q>,V extends Vector2<Q,U,V,SI,H>,SI extends Vector2<SIQuantity,SIUnit,SI,?,?>,H extends Vector2<?,?,?,?,?>>

Returns:

a String with the value contents, without the type, with the unit attached.