uk.ac.starlink.diva.interp

Interface Interpolator

All Known Implementing Classes:

AbstractInterpolator, AkimaSplineInterp, CubicSplineInterp, HermiteSplineInterp, LinearInterp, PolynomialInterp

public interface Interpolator

Interface that all interpolators should implement. Interpolation assumes a monotonic set of X coordinates (the ordinates) and an arbitrary set of Y coordinates (the data values). Interpolation of the Y coordinates is provided by the specification of any possible X coordinate or array of X coordinates.

Version:

$Id$

Author:

Peter W. Draper

See Also:

AbstractInterpolator

Method Summary

Modifier and Type	Method and Description
void	appendValue(double newx, double newy) Append a new position to the existing coordinates.
double	evalYData(double xp) Return the interpolated value corresponding to some arbitrary X coordinate.
double[]	evalYDataArray(double[] xps) Return an array of interpolated value corresponding to some array of arbitrary X coordinates.
int	getCount() Get the number of coordinate positions that are being used by this interpolator.
double	getXCoord(int index) Get an X coordinate by index.
double[]	getXCoords() Get the X coordinates.
double	getYCoord(int index) Get a Y coordinate by index.
double[]	getYCoords() Get the Y coordinates.
double	interpolate(double xp) Return the interpolated value corresponding to some arbitrary X coordinate.
boolean	isFull() Return if the Interpolator is full.
boolean	isIncreasing() Return the direction being used by this interpolator.
void	setCoords(double[] x, double[] y, boolean check) Set or reset the coordinates used by this interpolator.
int	stepGuess() A guess at the number of steps needed between the actual X coordinates that may be used to draw a reasonable representation of the curve being interpolated.

Method Detail

stepGuess

int stepGuess()

A guess at the number of steps needed between the actual X coordinates that may be used to draw a reasonable representation of the curve being interpolated.

setCoords

void setCoords(double[] x,
               double[] y,
               boolean check)

Set or reset the coordinates used by this interpolator.

Parameters:

x - the X coordinates.

y - the Y coordinates.

check - whether to check the monotonic direction (compares 0 and 1 values of x). Use this when you need to preserve the direction temporarily even though the order may currently be switched, but take care to reorder before interpolating.

isIncreasing

boolean isIncreasing()

Return the direction being used by this interpolator.

appendValue

void appendValue(double newx,
                 double newy)

Append a new position to the existing coordinates.

Parameters:

x - the X coordinate.

y - the Y coordinate.

getCount

int getCount()

Get the number of coordinate positions that are being used by this interpolator.

Returns:

the number of positions that will be used.

isFull

boolean isFull()

Return if the Interpolator is full. This may mean that the instance will ignore or refuse any further vectices.

getXCoords

double[] getXCoords()

Get the X coordinates.

Returns:

the X coordinate array. Note this is not a copy, if you modify it you need to re-apply setCoords.

getXCoord

double getXCoord(int index)

Get an X coordinate by index. If the index is invalid an out of bound exception will be thrown.

Returns:

the X coordinate.

getYCoords

double[] getYCoords()

Get the Y coordinates.

Returns:

the Y coordinate array. Note this is not a copy, if you modify it you need to re-apply setCoords.

getYCoord

double getYCoord(int index)

Get a Y coordinate by index. If the index is invalid an out of bound exception will be thrown.

Returns:

the Y coordinate.

interpolate

double interpolate(double xp)

Return the interpolated value corresponding to some arbitrary X coordinate.

Parameters:

xp - the X coordinate at which an interpolated Y coordinate is required.

Returns:

the interpolated value.

evalYData

double evalYData(double xp)

Return the interpolated value corresponding to some arbitrary X coordinate.

Parameters:

xp - the X coordinate at which an interpolated Y coordinate is required.

Returns:

the interpolated value.

evalYDataArray

double[] evalYDataArray(double[] xps)

Return an array of interpolated value corresponding to some array of arbitrary X coordinates.

Parameters:

xps - the X coordinates at which interpolated Y coordinates are required.

Returns:

the interpolated values.