geometry
Class Point

java.lang.Object
  geometry.Point

All Implemented Interfaces:

Geometry

public class Point

extends java.lang.Object

implements Geometry

Represents a point in n-dimensional space, defined by a vector containing the coordinats of this point.

Author:

karsten

Field Summary

protected Vector

coords A vector containig the coordinats of this point.

Constructor Summary

Point(double[] coords)
Constructs a point with the given coordinates.

Point(int dim)
Constructs the origin of the given dimension.

Point(int dim, int coord)
Constructs a point from a unit coordinate-vector.

Point(Vector v)
Constructs a point with the coordinates given by a vector.

Method Summary

AffineSpace	affineClosure() Computes the smallest affine space, which contains this geometry
boolean	canBeContainedIn(Geometry other) Tests, if this geometry knows how to test if is contained in another geometry.
boolean	canContain(Geometry other) Tests, if this geometry knows how to test if it contains another geometry.
boolean	canIntersect(Geometry other) Tests, if this geometry knows how to intersect itself with another geometry.
boolean	contains(Geometry other) Tests, if this geometry contains another geometry.
Point	copy() Returns a deep copy of this point.
int	dim() Returns the dimension of this geometry.
double	getCoord(int i) Gets the i-th coordinate of this point.
Vector	getNormal(Point p) Returns a normal vector onto a hypersurface in a given point (only possible if dim()+1 == outerDim())
Point	getOrigin() The origin of the local coordinate system.
Geometry	getRandomRay(Point origin) Construct a random one-dimensional submanifold, containing a given point.
Vector	getVector() Constructs a point with the coordinates given by a vector.
Vector	getVectorTo(Point other) Computes the vector from this point to another point.
Geometry	intersection(Geometry other) Intersects this geometry with another.
boolean	isContainedIn(Geometry other) Tests, if this geometry is contained in another geometry.
Point	localization(Point p) Converts a point (which is contained in the geometry) to coordinates local to the geometry.
int	outerDim() Returns the dimension of the space containg this point.
void	setCoord(int i, double value) Sets the i-th coordinate of this point to a given value.
java.awt.Shape	toShape(java.awt.geom.AffineTransform transform) Returns the cell as Shape (only possible for 2-dimensional Complexes).
java.lang.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

Field Detail

coords

protected Vector coords

A vector containig the coordinats of this point.

Constructor Detail

Point

public Point(int dim)

Constructs the origin of the given dimension. All entries will be zero.

Parameters:

dim - the number of coordinates

Point

public Point(int dim,
             int coord)

Constructs a point from a unit coordinate-vector. All entries except one will be zero.

Parameters:

dim - the number of coordinates

coord - the index of the only non-zero coordinate of this point

Point

public Point(double[] coords)

Constructs a point with the given coordinates. Attention: The first entry coords[0] will be the first entry of the vecor get(1)

Parameters:

coords - the coordinates of this point

Point

public Point(Vector v)

Constructs a point with the coordinates given by a vector. The coordinates are not copied from the vector!

Parameters:

v - a vector containing the coordinates of this point

Method Detail

getVector

public Vector getVector()

Constructs a point with the coordinates given by a vector. The coordinates are not copied from the vector!

Returns:

a vector containing the coordinates of this point

getVectorTo

public Vector getVectorTo(Point other)

Computes the vector from this point to another point.

Parameters:

other - another point

Returns:

a vector from this point to the other point

toShape

public java.awt.Shape toShape(java.awt.geom.AffineTransform transform)

Description copied from interface: Geometry

Returns the cell as Shape (only possible for 2-dimensional Complexes).

Specified by:

toShape in interface Geometry

Returns:

intersection as Shape

affineClosure

public AffineSpace affineClosure()

Description copied from interface: Geometry

Computes the smallest affine space, which contains this geometry

Specified by:

affineClosure in interface Geometry

Returns:

the affine closure of this geometry

setCoord

public void setCoord(int i,
                     double value)

Sets the i-th coordinate of this point to a given value. The first index is 1.

Parameters:

i - the index of the changing coordinate

value - the new value for the selected coordinate

getCoord

public double getCoord(int i)

Gets the i-th coordinate of this point. The first index is 1.

Parameters:

i - the index of a coordinate

Returns:

the value at the selected coordinate

outerDim

public int outerDim()

Returns the dimension of the space containg this point.

Specified by:

outerDim in interface Geometry

Returns:

the number of coordinates of this point

dim

public int dim()

Description copied from interface: Geometry

Returns the dimension of this geometry.

Specified by:

dim in interface Geometry

canContain

public boolean canContain(Geometry other)

Description copied from interface: Geometry

Tests, if this geometry knows how to test if it contains another geometry. If the other geometry is a point, this has to be true.

Specified by:

canContain in interface Geometry

Parameters:

other - another geometry

Returns:

true if the method contains will work

contains

public boolean contains(Geometry other)

Description copied from interface: Geometry

Tests, if this geometry contains another geometry. If this geometry doesn't know, how to test this, it will throw an UnsupportedOperationException. This will happen only if canContain returns false.

Specified by:

contains in interface Geometry

Parameters:

other - another geometry

Returns:

true iff other is contained in the geometry.

canBeContainedIn

public boolean canBeContainedIn(Geometry other)

Description copied from interface: Geometry

Tests, if this geometry knows how to test if is contained in another geometry.

Specified by:

canBeContainedIn in interface Geometry

Parameters:

other - another geometry

Returns:

true if the method isContainedIn will work

isContainedIn

public boolean isContainedIn(Geometry other)

Description copied from interface: Geometry

Tests, if this geometry is contained in another geometry. If this geometry doesn't know, how to test this, it will throw an UnsupportedOperationException. This will happen only if canBeContainedIn returns false.

Specified by:

isContainedIn in interface Geometry

Parameters:

other - another geometry

Returns:

true iff this geometry contains other.

canIntersect

public boolean canIntersect(Geometry other)

Description copied from interface: Geometry

Tests, if this geometry knows how to intersect itself with another geometry.

Specified by:

canIntersect in interface Geometry

Parameters:

other - another geometry, which is to be intersected

Returns:

true if the method intersection will work

intersection

public Geometry intersection(Geometry other)

Description copied from interface: Geometry

Intersects this geometry with another. The intersection will be null, if the two geometries do not intersect. If this geometry doesn't know, how to intersect itself with the other geometry, it will throw an UnsupportedOperationException. This will happen only if canIntersect returns false.

Specified by:

intersection in interface Geometry

Parameters:

other - another geometry, which is to be intersected

Returns:

the intersection of the two geometries

localization

public Point localization(Point p)

Description copied from interface: Geometry

Converts a point (which is contained in the geometry) to coordinates local to the geometry. The result will be a point containing dim() coordinates. The dimension of this geometry has to be nonzero.

Specified by:

localization in interface Geometry

Parameters:

p - a point contained in this geometry

Returns:

local coordinates of this point

getOrigin

public Point getOrigin()

Description copied from interface: Geometry

The origin of the local coordinate system.

Specified by:

getOrigin in interface Geometry

Returns:

the point whose localization is zero.

getNormal

public Vector getNormal(Point p)

Description copied from interface: Geometry

Returns a normal vector onto a hypersurface in a given point (only possible if dim()+1 == outerDim())

Specified by:

getNormal in interface Geometry

Parameters:

p - the starting point of the normal vector

Returns:

a vector orthogonal to the space in the point p

getRandomRay

public Geometry getRandomRay(Point origin)

Description copied from interface: Geometry

Construct a random one-dimensional submanifold, containing a given point. The point will become the origin of the compuded submanifold. The dimension of this geometry has to be nonzero.

Specified by:

getRandomRay in interface Geometry

Parameters:

origin - a point contained in this geometry

Returns:

a one-dimensional geometry, contained in this geometry, and containing the given origin

toString

public java.lang.String toString()

Returns a String representation of this vector.

Returns:

a string containing every coordinate of this point

copy

public Point copy()

Returns a deep copy of this point.