Vector2DReadOnly

All Superinterfaces:

Tuple2DReadOnly

All Known Subinterfaces:

Vector2DBasics

All Known Implementing Classes:

Vector2D, Vector2D32
```
public interface Vector2DReadOnly
extends Tuple2DReadOnly
```
Read-only interface for a 2 dimensional vector.
A 2D vector represents a physical quantity with a magnitude and a direction in the XY-plane. For instance, it can be used to represent a 2D velocity, force, or translation from one 2D point to another.

Although a point and vector hold onto the same type of information, the distinction is made between them as they represent different geometry objects and are typically not handled the same way:
- a point represents the coordinate of a location in space. A notable difference with a vector is that the distance between two points has a physical meaning. When a point is transformed with a homogeneous transformation matrix, a point's coordinates are susceptible to be scaled, rotated, and translated.
- a vector is not constrained to a location in space. Instead, a vector represents some physical quantity that has a direction and a magnitude such as: a velocity, a force, the translation from one point to another, etc. When a vector is transformed with a homogeneous transformation matrix, its components are susceptible to be scaled and rotated, but never to be translated.
Author:

Sylvain Bertrand

Method Summary

All Methods Static Methods Instance Methods Default Methods
Modifier and Type	Method	Description
`default double`	`angle(Vector2DReadOnly other)`	Calculates and returns the angle in radians from this vector to `other`.
`default double`	`cross(Tuple2DReadOnly tuple)`	Calculates and returns the value of the cross product of this vector with `tuple`.
`static double`	`cross(Tuple2DReadOnly tuple1, Tuple2DReadOnly tuple2)`	Calculates and returns the value of the cross product of `tuple1` with `tuple2`.
`default double`	`dot(Vector2DReadOnly other)`	Calculates and returns the value of the dot product of this vector with `other`.
`default boolean`	`geometricallyEquals(Vector2DReadOnly other, double epsilon)`	Tests if `this` and `other` represent the same vector 2D to an `epsilon`.
`default double`	`length()`	Calculates and returns the magnitude of this vector.
`default double`	`lengthSquared()`	Calculates and returns the square of the magnitude of this vector.

Methods inherited from interface us.ihmc.euclid.tuple2D.interfaces.Tuple2DReadOnly
containsNaN, epsilonEquals, equals, get, get, get, get, get, get, get, getElement, getElement32, getX, getX32, getY, getY32

- Method Detail
  - length
```
default double length()
```
    Calculates and returns the magnitude of this vector.
    length = √(x² + y²)
    
    Returns:
    
    the magnitude of this vector.
  - lengthSquared
```
default double lengthSquared()
```
    Calculates and returns the square of the magnitude of this vector.
    length² = x² + y²
    
    This method is usually preferred over length() when calculation speed matters and knowledge of the actual magnitude does not, i.e. when comparing several vectors by theirs magnitude.
    
    Returns:
    
    the square of the magnitude of this vector.
  - dot
```
default double dot(Vector2DReadOnly other)
```
    Calculates and returns the value of the dot product of this vector with other.
    For instance, the dot product of two vectors p and q is defined as:
    p . q = ∑_i=1:2(p_i * q_i)
    
    Parameters:
    
    other - the other vector used for the dot product. Not modified.
    
    Returns:
    
    the value of the dot product.
  - angle
```
default double angle(Vector2DReadOnly other)
```
    Calculates and returns the angle in radians from this vector to other.
    The computed angle is in the range [-pi; pi].
    
    Parameters:
    
    other - the other vector used to compute the angle. Not modified.
    
    Returns:
    
    the value of the angle from this vector to other.
  - cross
```
default double cross(Tuple2DReadOnly tuple)
```
    Calculates and returns the value of the cross product of this vector with tuple.
    
    Parameters:
    
    tuple - the second term in the cross product. Not modified.
    
    Returns:
    
    the value of the cross product.
  - cross
```
static double cross(Tuple2DReadOnly tuple1,
                    Tuple2DReadOnly tuple2)
```
    Calculates and returns the value of the cross product of tuple1 with tuple2.
    
    Parameters:
    
    tuple1 - the first tuple in the cross product. Not modified.
    
    tuple2 - the second tuple in the cross product. Not modified.
    
    Returns:
    
    the value of the cross product.
  - geometricallyEquals
```
default boolean geometricallyEquals(Vector2DReadOnly other,
                                    double epsilon)
```
    Tests if this and other represent the same vector 2D to an epsilon.
    Two vectors are considered geometrically equal if the length of their difference is less than or equal to epsilon.
    
    Note that this.geometricallyEquals(other, epsilon) == true does not necessarily imply this.epsilonEquals(other, epsilon) and vice versa.
    
    Parameters:
    
    other - the other vector 2D to compare against this. Not modified.
    
    epsilon - the maximum length of the difference vector can be for the two vectors to be considered equal.
    
    Returns:
    
    true if the two vectors represent the same geometry, false otherwise.

Interface Vector2DReadOnly

Method Summary

Methods inherited from interface us.ihmc.euclid.tuple2D.interfaces.Tuple2DReadOnly

Method Detail

length

lengthSquared

dot

angle

cross

cross

geometricallyEquals