Package com.xinapse.numerical

Class CubicSplineInterpolator

java.lang.Object

com.xinapse.numerical.AbstractInterpolator

com.xinapse.numerical.CubicSplineInterpolator

All Implemented Interfaces:

Serializable

public class CubicSplineInterpolator
extends com.xinapse.numerical.AbstractInterpolator
implements Serializable

A cubic spline interpolator for tabulated values of (x,y).

See Also:

• Serialized Form

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	CubicSplineInterpolator(double[] x, double[] y)	Create a new CubicSplineInterpolator interpolator, from arrays of tabulated x and y values.

Method Summary

Modifier and Type	Method	Description
double	getFirstDeriv(double xPt)	Returns the first derivative of the function value at a given value of x.
double	getSecondDeriv(double xPt)	Returns the second derivative of the function value at a given value of x.
double[]	getSecondDerivs()	Returns the internal array of second derivatives values at the knots.
double	interpolate(double xPt)	Returns an interpolated value of y for a value of x.
static CubicSplineInterpolator	newInstance(double[] x, double[] y)	Create a new CubicSplineInterpolator interpolator, from arrays of tabulated x and y values.
static CubicSplineInterpolator	newInstance(double[] x, float[] y)	Create a new CubicSplineInterpolator interpolator, from arrays of tabulated x and y values.
static CubicSplineInterpolator	newInstance(float[] x, float[] y)	Create a new CubicSplineInterpolator interpolator, from arrays of tabulated x and y values.
void	setEndDerivs(double dydx1, double dydxn)	Set the first derivative values of the CubicSplineInterpolator at the end points of the abscissa range, overriding a natural spline.

Methods inherited from class com.xinapse.numerical.AbstractInterpolator

getLimits, orderPoints

Methods inherited from class java.lang.Object

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

Constructor Details

CubicSplineInterpolator

protected CubicSplineInterpolator(double[] x,
 double[] y)
                           throws InvalidArgumentException

Create a new CubicSplineInterpolator interpolator, from arrays of tabulated x and y values. The values in the two arrays are copied, and therefore the arrays can be reused.

Parameters:

x - the array of x-values.

y - the array of y-values.

Throws:

InvalidArgumentException - if the x- and y arrays are of different lengths.

Method Details

newInstance

public static CubicSplineInterpolator newInstance(float[] x,
 float[] y)
                                           throws InvalidArgumentException

Create a new CubicSplineInterpolator interpolator, from arrays of tabulated x and y values. The values in the two arrays are copied, and therefore the arrays can be reused.

Parameters:

x - the array of x-values.

y - the array of y-values.

Returns:

a new CubicSplineInterpolator interpolator.

Throws:

InvalidArgumentException - if the x- and y arrays are of different lengths.

newInstance

public static CubicSplineInterpolator newInstance(double[] x,
 float[] y)
                                           throws InvalidArgumentException

Create a new CubicSplineInterpolator interpolator, from arrays of tabulated x and y values. The values in the two arrays are copied, and therefore the arrays can be reused.

Parameters:

x - the array of x-values.

y - the array of y-values.

Returns:

a new CubicSplineInterpolator interpolator.

Throws:

InvalidArgumentException - if the x- and y arrays are of different lengths.

newInstance

public static CubicSplineInterpolator newInstance(double[] x,
 double[] y)
                                           throws InvalidArgumentException

Create a new CubicSplineInterpolator interpolator, from arrays of tabulated x and y values. The values in the two arrays are copied, and therefore the arrays can be reused.

Parameters:

x - the array of x-values.

y - the array of y-values.

Returns:

a new CubicSplineInterpolator interpolator.

Throws:

InvalidArgumentException - if the x- and y arrays are of different lengths.

setEndDerivs

public void setEndDerivs(double dydx1,
 double dydxn)

Set the first derivative values of the CubicSplineInterpolator at the end points of the abscissa range, overriding a natural spline.

Parameters:

dydx1 - the first derivative value at the left-hand end of the abscissa range.

dydxn - the first derivative value at the right-hand end of the abscissa range.

getSecondDerivs

public double[] getSecondDerivs()

Returns the internal array of second derivatives values at the knots.

Returns:

the internal array of second derivatives values.

interpolate

public double interpolate(double xPt)

Returns an interpolated value of y for a value of x. If the x-value lies outside the range of the tabulated values, linear extrapolation is used.

Specified by:

interpolate in class com.xinapse.numerical.AbstractInterpolator

Parameters:

xPt - the x value for which to return the interpolated y-value.

Returns:

the interpolated value of y for a value of x.

getFirstDeriv

public double getFirstDeriv(double xPt)

Returns the first derivative of the function value at a given value of x.

Parameters:

xPt - the x value for which to return the first derivative value.

Returns:

the first derivative of the function value at a given value of x.

getSecondDeriv

public double getSecondDeriv(double xPt)

Returns the second derivative of the function value at a given value of x.

Parameters:

xPt - the x value for which to return the second derivative value.

Returns:

the second derivative of the function value at a given value of x.