Real2 (CML Euclid 2.9 API)

java.lang.Object
- org.xmlcml.euclid.Real2

All Implemented Interfaces:

EuclidConstants

Direct Known Subclasses:

Complex, Point2, Vector2
```
public class Real2
extends Object
implements EuclidConstants
```
A pair of FPt numbers with no other assumptions Contains two doubles Can be used as it is, but there are some specialised derived classes (for example Complex (a complex number), Point2 (x,y coords), etc), The default value is 0.0, 0.0.

Author:

(C) P. Murray-Rust, 1996

Field Summary

Fields
Modifier and Type Field and Description

double x
the first floating point value

double y
the second floating point value
- Fields inherited from interface org.xmlcml.euclid.EuclidConstants
  C_AMP, C_APOS, C_ATSIGN, C_BACKSLASH, C_BACKSPACE, C_CARET, C_COLON, C_COMMA, C_DEL, C_DOLLAR, C_EQUALS, C_FORMFEED, C_HASH, C_LANGLE, C_LBRAK, C_LCURLY, C_LSQUARE, C_MINUS, C_NBSP, C_NEWLINE, C_NL, C_PERCENT, C_PERIOD, C_PIPE, C_PLUS, C_POUND, C_QUERY, C_QUOT, C_RANGLE, C_RBRAK, C_RCURLY, C_RETURN, C_RSQUARE, C_SEMICOLON, C_SHRIEK, C_SLASH, C_SPACE, C_STAR, C_TAB, C_TILDE, C_UNDER, EPS, F_S, NONWHITEPUNC, NONWHITEPUNC0, NONWHITEPUNC0REGEX, ONE_THIRD, PUNC, S_AMP, S_APOS, S_ATSIGN, S_BACKSLASH, S_CARET, S_COLON, S_COMMA, S_DOLLAR, S_EMPTY, S_EQUALS, S_FORMFEED, S_HASH, S_LANGLE, S_LBRAK, S_LCURLY, S_LSQUARE, S_MINUS, S_NEWLINE, S_NL, S_PERCENT, S_PERIOD, S_PIPE, S_PLUS, S_POUND, S_QUERY, S_QUOT, S_RANGLE, S_RBRAK, S_RCURLY, S_RETURN, S_RSQUARE, S_SEMICOLON, S_SHRIEK, S_SLASH, S_SPACE, S_STAR, S_TAB, S_TILDE, S_UNDER, S_WHITEREGEX, TWO_THIRDS, U_S, WHITESPACE

Fields
Modifier and Type	Field and Description
`double`	`x` the first floating point value
`double`	`y` the second floating point value

Constructor Summary

Constructors
Constructor and Description
`Real2()` constructor.
`Real2(double[] x)` constructor.
`Real2(double x, double y)` constructor.
`Real2(Int2 int2)` constructor.
`Real2(int x, int y)` constructor.
`Real2(Real2 r)` copy constructor
`Real2(String s)` two reals separated by whitespace OR (real, real)
`Real2(String s, String delimiter)` two integers separated by delimiter

Method Summary

All Methods Static Methods Instance Methods Concrete Methods Deprecated Methods
Modifier and Type	Method and Description
`static Real2[]`	`addPolygonOnLine(Real2 point1, Real2 point2, int nPoints, int end, Real2 repelPoint)` creates a polygon returns a point array from two points Serial numbers of points are 0 and end that is point1 is points[0] and point2 is points[end] if end == 0, end =>1
`void`	`clear()` set to 0 0
`static Real2`	`createFromString(String s)` reads output format from toString() "(x,y)"
`double`	`dotProduct(Real2 r)` get dot product
`double`	`elementAt(int elem)` get either value counts from ZERO
`Real2`	`format(int places)` round to decimal places.
`double`	`getAngle()` get angle between origin and this point (i.e polar coords) - uses atan2 (that is anticlockwise from X axis); if x == y == 0.0 presumably returns NaN
`static Angle`	`getAngle(Real2 p1, Real2 p2, Real2 p3)` get angle between 3 Real2s (the second is in the centre)
`static Real2`	`getCentroid(List<Real2> p2Vector)` get centroid of all points.
`double`	`getDistance(Real2 r)` get distance to another Real2
`static RealMatrix`	`getDistanceMatrix(List<Real2> coords1, List<Real2> coords2)` get rectangular distance matrix.
`double`	`getLength()` get length of Real2 if centered on origin
`Real2`	`getMidPoint(Real2 p)` point midway between 'this' and 'p'
`static int`	`getSerialOfNearestPoint(List<Real2> p2v, Real2 point)` get serialNumber of nearest point
`double`	`getSquaredDistance(Real2 r)` get squared distance to another Real2
`Real2`	`getTransformed(Transform2 t)` gets a point transformed by a rot-trans matrix does NOT MODIFY 'this'
`Real2`	`getUnitVector()` get unit vector
`double`	`getX()` get X value
`double[]`	`getXY()` get x y as array.
`double`	`getY()` get Y value
`boolean`	`isEqualTo(Real2 r)` Deprecated.
`boolean`	`isEqualTo(Real2 r, double eps)` equality.
`boolean`	`isOrigin()` Deprecated. USE epsilon method
`boolean`	`isOrigin(double epsilon)` is the point the origin.
`Real2`	`makePoint(double rad, double theta)` make a new point at (dist, theta) from this
`Real2`	`multiplyBy(double f)` retuen multiplication of a point by a scalar does not alter this
`void`	`multiplyEquals(double f)` multiply a point by a scalar alters this
`void`	`negative()` multiply both components by minus one MODIFIES 'this'
`Real2`	`plus(Real2 r2)` add two points to give vector sum
`void`	`plusEquals(Real2 r2)` add two points to give vector sum
`void`	`setX(double xx)` set x.
`void`	`setY(double yy)` set y.
`void`	`sortAscending()` sorts x and y so that x <= y
`void`	`sortDescending()` sorts x and y so that x >= y
`Real2`	`subtract(Real2 r2)` subtract two points to give vector difference
`void`	`swap()` swaps the x and y values
`String`	`toString()` to string.
`void`	`transformBy(Transform2 t)` transforms the point by a rot-trans matrix MODIFIES 'this' Note the next routine is often better

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Field Detail
  - x
```
public double x
```
    the first floating point value
  - y
```
public double y
```
    the second floating point value
- Constructor Detail
  - Real2
```
public Real2()
```
    constructor.
  - Real2
```
public Real2(double x,
             double y)
```
    constructor.
    
    Parameters:
    
    x - the first floating point value
    
    y - the second floating point value
  - Real2
```
public Real2(int x,
             int y)
```
    constructor.
    
    Parameters:
    
    x - the first integer value
    
    y - the second integer value
  - Real2
```
public Real2(Int2 int2)
```
    constructor.
    
    Parameters:
    
    int2 - An object of type Int2 containing two integer values
  - Real2
```
public Real2(String s)
```
    two reals separated by whitespace OR (real, real)
    
    Parameters:
    
    s - the string containing two reals separated by whitespace
  - Real2
```
public Real2(String s,
             String delimiter)
```
    two integers separated by delimiter
    
    Parameters:
    
    s - the string containing two integers separated by delimiter
    
    delimiter - the delimiter
  - Real2
```
public Real2(double[] x)
```
    constructor.
    
    Parameters:
    
    x - the two components
  - Real2
```
public Real2(Real2 r)
```
    copy constructor
    
    Parameters:
    
    r - the real object to be copied
- Method Detail
  - createFromString
```
public static Real2 createFromString(String s)
```
    reads output format from toString() "(x,y)"
    
    Parameters:
    
    s - string representation of real, "(x,y)"
    
    Returns:
  - swap
```
public void swap()
```
    swaps the x and y values
  - sortAscending
```
public void sortAscending()
```
    sorts x and y so that x <= y
  - sortDescending
```
public void sortDescending()
```
    sorts x and y so that x >= y
  - clear
```
public void clear()
```
    set to 0 0
  - setX
```
public void setX(double xx)
```
    set x.
    
    Parameters:
    
    xx - floating point x value to be set
  - setY
```
public void setY(double yy)
```
    set y.
    
    Parameters:
    
    yy - floating point y value to be set
  - isEqualTo
```
public boolean isEqualTo(Real2 r)
```
    Deprecated.
    
    equality.
    
    Parameters:
    
    r - to test
    
    Returns:
    
    equals
  - isEqualTo
```
public boolean isEqualTo(Real2 r,
                         double eps)
```
    equality.
    
    Parameters:
    
    r - to test
    
    eps - tolerance
    
    Returns:
    
    equals
  - isOrigin
```
public boolean isOrigin()
```
    Deprecated. USE epsilon method
    
    is the point the origin.
    
    Returns:
    
    true if origin
  - isOrigin
```
public boolean isOrigin(double epsilon)
```
    is the point the origin.
    
    Parameters:
    
    epsilon - Epsilon
    
    Returns:
    
    true if origin
  - plus
```
public Real2 plus(Real2 r2)
```
    add two points to give vector sum
    
    Parameters:
    
    r2 - the specified real to be added with this real
    
    Returns:
    
    point
  - plusEquals
```
public void plusEquals(Real2 r2)
```
    add two points to give vector sum
    
    Parameters:
    
    r2 - the specified real to be added and assigned with this real
  - subtract
```
public Real2 subtract(Real2 r2)
```
    subtract two points to give vector difference
    
    Parameters:
    
    r2 - the specified real to be subtracted from this real
    
    Returns:
    
    point
  - negative
```
public void negative()
```
    multiply both components by minus one MODIFIES 'this'
  - multiplyBy
```
public Real2 multiplyBy(double f)
```
    retuen multiplication of a point by a scalar does not alter this
    
    Parameters:
    
    f - a floating point scalar value
    
    Returns:
    
    point
  - multiplyEquals
```
public void multiplyEquals(double f)
```
    multiply a point by a scalar alters this
    
    Parameters:
    
    f - a floating point scalar value
  - getX
```
public double getX()
```
    get X value
    
    Returns:
    
    x value
  - getY
```
public double getY()
```
    get Y value
    
    Returns:
    
    y value
  - elementAt
```
public double elementAt(int elem)
                 throws EuclidRuntimeException
```
    get either value counts from ZERO
    
    Parameters:
    
    elem - index of element
    
    Returns:
    
    value
    
    Throws:
    
    EuclidRuntimeException
  - getLength
```
public double getLength()
```
    get length of Real2 if centered on origin
    
    Returns:
    
    length
  - getDistance
```
public double getDistance(Real2 r)
```
    get distance to another Real2
    
    Parameters:
    
    r - the specified real to be measured against this real
    
    Returns:
    
    distance
  - getSquaredDistance
```
public double getSquaredDistance(Real2 r)
```
    get squared distance to another Real2
    
    Parameters:
    
    r - the specified real to be measured against this real
    
    Returns:
    
    dist2
  - getMidPoint
```
public Real2 getMidPoint(Real2 p)
```
    point midway between 'this' and 'p'
    
    Parameters:
    
    p - the specified real to be measured against this real
    
    Returns:
    
    midpoint
  - getUnitVector
```
public Real2 getUnitVector()
```
    get unit vector
    
    Returns:
    
    unit vector
    
    Throws:
    
    EuclidRuntimeException - this was of zero length
  - dotProduct
```
public double dotProduct(Real2 r)
```
    get dot product
    
    Parameters:
    
    r - the specified real to be measured against this real
    
    Returns:
    
    dot
  - getAngle
```
public static Angle getAngle(Real2 p1,
                             Real2 p2,
                             Real2 p3)
```
    get angle between 3 Real2s (the second is in the centre)
    
    Parameters:
    
    p1 - point 1
    
    p2 - point 2
    
    p3 - point 3
    
    Returns:
    
    angle is CLOCKWISE from p1 to p3
  - transformBy
```
public void transformBy(Transform2 t)
```
    transforms the point by a rot-trans matrix MODIFIES 'this' Note the next routine is often better
    
    Parameters:
    
    t - rot-trans matrix
  - getTransformed
```
public Real2 getTransformed(Transform2 t)
```
    gets a point transformed by a rot-trans matrix does NOT MODIFY 'this'
    
    Parameters:
    
    t - rot-trans matrix
    
    Returns:
    
    point
  - addPolygonOnLine
```
public static Real2[] addPolygonOnLine(Real2 point1,
                                       Real2 point2,
                                       int nPoints,
                                       int end,
                                       Real2 repelPoint)
```
    creates a polygon returns a point array from two points Serial numbers of points are 0 and end that is point1 is points[0] and point2 is points[end] if end == 0, end =>1
    
    Parameters:
    
    point1 - starting point
    
    nPoints - number of points in the resulting polygon
    
    point2 - ending point
    
    end - index of point2 in points array
    
    repelPoint - repel point
    
    Returns:
    
    points
  - getAngle
```
public double getAngle()
```
    get angle between origin and this point (i.e polar coords) - uses atan2 (that is anticlockwise from X axis); if x == y == 0.0 presumably returns NaN
    
    Returns:
    
    angle
  - makePoint
```
public Real2 makePoint(double rad,
                       double theta)
```
    make a new point at (dist, theta) from this
    
    Parameters:
    
    rad - the distance to new point
    
    theta - the angle to new point (anticlockwise from X axis), that is theta=0 gives (rad, 0), theta=PI/2 gives (0, rad)
    
    Returns:
    
    Real2 new point
  - getCentroid
```
public static Real2 getCentroid(List<Real2> p2Vector)
```
    get centroid of all points. does not modify this
    
    Parameters:
    
    p2Vector - list of all real points
    
    Returns:
    
    the centroid
  - getSerialOfNearestPoint
```
public static int getSerialOfNearestPoint(List<Real2> p2v,
                                          Real2 point)
```
    get serialNumber of nearest point
    
    Parameters:
    
    p2v - list of all real points
    
    point - point wrt which serialNumber is calculated
    
    Returns:
    
    serial
  - getDistanceMatrix
```
public static RealMatrix getDistanceMatrix(List<Real2> coords1,
                                           List<Real2> coords2)
```
    get rectangular distance matrix. matrix need not be square or symmetric unless coords == coords2 d(ij) is distance between coord(i) and coords2(j).
    
    Parameters:
    
    coords1 - first coordinate of the rectangle
    
    coords2 - second coordinate of the rectangle
    
    Returns:
    
    distance matrix
  - toString
```
public String toString()
```
    to string.
    
    Overrides:
    
    toString in class Object
    
    Returns:
    
    string
  - getXY
```
public double[] getXY()
```
    get x y as array.
    
    Returns:
    
    array of length 2
  - format
```
public Real2 format(int places)
```
    round to decimal places.
    
    Parameters:
    
    places - max number of decimals (3 = ****.ddd)
    
    Returns:
    
    this

Class Real2

Field Summary

Fields inherited from interface org.xmlcml.euclid.EuclidConstants

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

x

y

Constructor Detail

Real2

Real2

Real2

Real2

Real2

Real2

Real2

Real2

Method Detail

createFromString

swap

sortAscending

sortDescending

clear

setX

setY

isEqualTo

isEqualTo

isOrigin

isOrigin

plus

plusEquals

subtract

negative

multiplyBy

multiplyEquals

getX

getY

elementAt

getLength

getDistance

getSquaredDistance

getMidPoint

getUnitVector

dotProduct

getAngle

transformBy

getTransformed

addPolygonOnLine

getAngle

makePoint

getCentroid

getSerialOfNearestPoint

getDistanceMatrix

toString

getXY

format