Class Vector2D

    • Field Detail

      • ZERO

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

        public static final Vector2D PLUS_I
        First canonical vector (coordinates: 1, 0).
        Since:
        1.6
      • MINUS_I

        public static final Vector2D MINUS_I
        Opposite of the first canonical vector (coordinates: -1, 0).
        Since:
        1.6
      • PLUS_J

        public static final Vector2D PLUS_J
        Second canonical vector (coordinates: 0, 1).
        Since:
        1.6
      • MINUS_J

        public static final Vector2D MINUS_J
        Opposite of the second canonical vector (coordinates: 0, -1).
        Since:
        1.6
      • 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 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 point belongs.
        Specified by:
        getSpace in interface Point<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,​Vector2D>
        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,​Vector2D>
        Returns:
        L1 norm for the vector
      • getNorm

        public double getNorm()
        Get the L2 norm for the vector.
        Specified by:
        getNorm in interface Vector<Euclidean2D,​Vector2D>
        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,​Vector2D>
        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,​Vector2D>
        Returns:
        L norm for the vector
      • angle

        public static double angle​(Vector2D v1,
                                   Vector2D v2)
                            throws MathRuntimeException
        Compute the angular separation between two vectors.

        This method computes the angular separation between two vectors using the dot product for well separated vectors and the cross product for almost aligned vectors. This allows to have a good accuracy in all cases, even for vectors very close to each other.

        Parameters:
        v1 - first vector
        v2 - second vector
        Returns:
        angular separation between v1 and v2
        Throws:
        MathRuntimeException - if either vector has a null norm
      • isNaN

        public boolean isNaN()
        Returns true if any coordinate of this point is NaN; false otherwise
        Specified by:
        isNaN in interface Point<Euclidean2D>
        Returns:
        true if any coordinate of this point 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,​Vector2D>
        Returns:
        true if any coordinate of this vector is infinite and none are NaN; false otherwise
      • distance1

        public double distance1​(Vector<Euclidean2D,​Vector2D> 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,​Vector2D>
        Parameters:
        p - second vector
        Returns:
        the distance between the instance and p according to the L1 norm
      • distance

        public double distance​(Point<Euclidean2D> p)
        Compute the distance between the instance and another point.
        Specified by:
        distance in interface Point<Euclidean2D>
        Parameters:
        p - second point
        Returns:
        the distance between the instance and p
      • distanceInf

        public double distanceInf​(Vector<Euclidean2D,​Vector2D> 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,​Vector2D>
        Parameters:
        p - second vector
        Returns:
        the distance between the instance and p according to the L norm
      • distanceSq

        public double distanceSq​(Vector<Euclidean2D,​Vector2D> 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,​Vector2D>
        Parameters:
        p - second vector
        Returns:
        the square of the distance between the instance and p
      • crossProduct

        public double crossProduct​(Vector2D p1,
                                   Vector2D p2)
        Compute the cross-product of the instance and the given points.

        The cross product can be used to determine the location of a point with regard to the line formed by (p1, p2) and is calculated as: \[ P = (x_2 - x_1)(y_3 - y_1) - (y_2 - y_1)(x_3 - x_1) \] with \(p3 = (x_3, y_3)\) being this instance.

        If the result is 0, the points are collinear, i.e. lie on a single straight line L; if it is positive, this point lies to the left, otherwise to the right of the line formed by (p1, p2).

        Parameters:
        p1 - first point of the line
        p2 - second point of the line
        Returns:
        the cross-product
        See Also:
        Cross product (Wikipedia)
      • distance1

        public static double distance1​(Vector2D p1,
                                       Vector2D p2)
        Compute the distance between two vectors according to the L1 norm.

        Calling this method is equivalent to calling: p1.subtract(p2).getNorm1() except that no intermediate vector is built

        Parameters:
        p1 - first vector
        p2 - second vector
        Returns:
        the distance between p1 and p2 according to the L1 norm
        Since:
        1.6
      • 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
      • orientation

        public static double orientation​(Vector2D p,
                                         Vector2D q,
                                         Vector2D r)
        Compute the orientation of a triplet of points.
        Parameters:
        p - first vector of the triplet
        q - second vector of the triplet
        r - third vector of the triplet
        Returns:
        a positive value if (p, q, r) defines a counterclockwise oriented triangle, a negative value if (p, q, r) defines a clockwise oriented triangle, and 0 if (p, q, r) are collinear or some points are equal
        Since:
        1.2
      • 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
      • equalsIeee754

        public boolean equalsIeee754​(Object other)
        Test for the equality of two 2D vectors.

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

        In compliance with IEEE754 handling, if any coordinates of any of the two vectors are NaN, then the vectors are considered different. This implies that Vector2D.NaN.equals(Vector2D.NaN) returns false despite the instance is checked against itself.

        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
        Since:
        2.1
      • 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,​Vector2D>
        Parameters:
        format - the custom format for components
        Returns:
        a string representation of this vector