org.vishia.math

Class CurveInterpolation

java.lang.Object

org.vishia.math.CurveInterpolation

public class CurveInterpolation
extends java.lang.Object

This class contains some static methods for curve interpolation with given setting points.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private static interface	CurveInterpolation.Get

Field Summary

Fields

Modifier and Type	Field and Description
private static CurveInterpolation.Get	getColumn
private static CurveInterpolation.Get	getSingle
static float[][]	points2Test The xr or x1 values are given from -1, 2, 7 10 in the first row for columns.
static float[][]	pointsTest
static java.lang.String	sVersion Version, history and license.
private static int[]	testIndex

Constructor Summary

Constructors

Constructor and Description
CurveInterpolation()

Method Summary

Modifier and Type	Method and Description
static float	linearInterpolation(float x, float[][] points, int ixstart)
static float	linearInterpolation(float xr, float xc, float[][] points, int ixstart) xc1 xc xc2 xr1 y1 yc1 yc2 ------dc1 xr y xr2 yr2 ycr2 y2 ------dc2
static float[][]	pointsTest()
private static int	search(float x, java.lang.Object points, int from, int to, int ixstart, CurveInterpolation.Get get) Binary search of x in points[...][0]
static float	splineInterpolation(float x, float[][] points, int ixstart) This spline interpolation has the following propertied: Any y-value in points is exactly represented by the associated x input.
static float	splineInterpolation(float xr, float xc, float[][] points, int ixstart)
static float[][]	test()
static float[][]	test2()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

sVersion

public static final java.lang.String sVersion

Version, history and license.

• 2015-09-26 Hartmut creation.

Copyright/Copyleft: For this source the LGPL Lesser General Public License, published by the Free Software Foundation is valid. It means:

1. You can use this source without any restriction for any desired purpose.
2. You can redistribute copies of this source to everybody.
3. Every user of this source, also the user of redistribute copies with or without payment, must accept this license for further using.
4. But the LPGL is not appropriate for a whole software product, if this source is only a part of them. It means, the user must publish this part of source, but don't need to publish the whole source of the own product.
5. You can study and modify (improve) this source for own using or for redistribution, but you have to license the modified sources likewise under this LGPL Lesser General Public License. You mustn't delete this Copyright/Copyleft inscription in this source file.

If you are intent to use this sources without publishing its usage, you can get a second license subscribing a special contract with the author.

See Also:

Constant Field Values

getColumn

private static CurveInterpolation.Get getColumn

getSingle

private static CurveInterpolation.Get getSingle

pointsTest

public static float[][] pointsTest

testIndex

private static int[] testIndex

points2Test

public static float[][] points2Test

The xr or x1 values are given from -1, 2, 7 10 in the first row for columns. The xc or x2 values are given from -1, 3, 8 12 in the first column for rows. The y values are shown in the row and column of the x values.

Constructor Detail

CurveInterpolation

public CurveInterpolation()

Method Detail

linearInterpolation

public static float linearInterpolation(float x,
                                        float[][] points,
                                        int ixstart)

splineInterpolation

public static float splineInterpolation(float x,
                                        float[][] points,
                                        int ixstart)

This spline interpolation has the following propertied:

• Any y-value in points is exactly represented by the associated x input. It means any point in points is exactly represented in the result.
• The middle point of a segment in points is exactly represented in the result.
• The slope (dx/dreturn) left and right from a point in points is identically, it is the middle value of slope of the both segments.
• The slope in the middle of a segment is exact the slope of the segment.

See the following plot. The red curve is a result curve, the green curve is the curve of points with 4 points.

Parameters:

x - input

points - array of ordered pair of numbers. points[...][0] is the x value. points[...][1] is the associated y-value. The x values have to be increasing.

ixstart - -1 if not used, possible index to enforce the search of x input in points. Result of #search(float, float[][], int).

Returns:

The associated y value to x.

linearInterpolation

public static float linearInterpolation(float xr,
                                        float xc,
                                        float[][] points,
                                        int ixstart)

          xc1   xc     xc2
   xr1    y1    yc1    yc2    ------dc1
   
   xr           y
   
   xr2    yr2   ycr2    y2    ------dc2
 
 

Parameters:

xr -

xc -

points -

ixstart -

Returns:

splineInterpolation

public static float splineInterpolation(float xr,
                                        float xc,
                                        float[][] points,
                                        int ixstart)

search

private static int search(float x,
                          java.lang.Object points,
                          int from,
                          int to,
                          int ixstart,
                          CurveInterpolation.Get get)

Binary search of x in points[...][0]

Parameters:

x -

points -

ixstart - check whether x is in the correct segment, then fast return.

Returns:

pointsTest

public static float[][] pointsTest()

test

public static float[][] test()

test2

public static float[][] test2()