Class PiecewiseBicubicSplineInterpolatingFunction

java.lang.Object

org.apache.commons.math3.analysis.interpolation.PiecewiseBicubicSplineInterpolatingFunction

All Implemented Interfaces:

BivariateFunction

public class PiecewiseBicubicSplineInterpolatingFunction
extends Object
implements BivariateFunction

Function that implements the bicubic spline interpolation. This implementation currently uses AkimaSplineInterpolator as the underlying one-dimensional interpolator, which requires 5 sample points; insufficient data will raise an exception when the value method is called.

Since:

3.4

Field Summary

Fields

Modifier and Type	Field	Description
private final double[][]	fval	Set of cubic splines patching the whole data grid
private static final int	MIN_NUM_POINTS	The minimum number of points that are needed to compute the function.
private final double[]	xval	Samples x-coordinates
private final double[]	yval	Samples y-coordinates

Constructor Summary

Constructors

Constructor	Description
PiecewiseBicubicSplineInterpolatingFunction(double[] x, double[] y, double[][] f)

Method Summary

Modifier and Type	Method	Description
boolean	isValidPoint(double x, double y)	Indicates whether a point is within the interpolation range.
private int	searchIndex(double c, double[] val, int offset, int count)
double	value(double x, double y)	Compute the value for the function.

Methods inherited from class Object

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

Field Details

MIN_NUM_POINTS

private static final int MIN_NUM_POINTS

The minimum number of points that are needed to compute the function.

See Also:

• Constant Field Values

xval

private final double[] xval

Samples x-coordinates

yval

private final double[] yval

Samples y-coordinates

fval

private final double[][] fval

Set of cubic splines patching the whole data grid

Constructor Details

PiecewiseBicubicSplineInterpolatingFunction

public PiecewiseBicubicSplineInterpolatingFunction(double[] x,
 double[] y,
 double[][] f)
                                            throws DimensionMismatchException,
NullArgumentException,
NoDataException,
NonMonotonicSequenceException

Parameters:

x - Sample values of the x-coordinate, in increasing order.

y - Sample values of the y-coordinate, in increasing order.

f - Values of the function on every grid point. the expected number of elements.

Throws:

NonMonotonicSequenceException - if x or y are not strictly increasing.

NullArgumentException - if any of the arguments are null

NoDataException - if any of the arrays has zero length.

DimensionMismatchException - if the length of x and y don't match the row, column height of f

Method Details

value

public double value(double x,
 double y)
             throws OutOfRangeException

Compute the value for the function.

Specified by:

value in interface BivariateFunction

Parameters:

x - Abscissa for which the function value should be computed.

y - Ordinate for which the function value should be computed.

Returns:

the value.

Throws:

OutOfRangeException

isValidPoint

public boolean isValidPoint(double x,
 double y)

Indicates whether a point is within the interpolation range.

Parameters:

x - First coordinate.

y - Second coordinate.

Returns:

true if (x, y) is a valid point.

Since:

3.3

searchIndex

private int searchIndex(double c,
 double[] val,
 int offset,
 int count)

Parameters:

c - Coordinate.

val - Coordinate samples.

offset - how far back from found value to offset for querying

count - total number of elements forward from beginning that will be queried

Returns:

the index in val corresponding to the interval containing c.

Throws:

OutOfRangeException - if c is out of the range defined by the boundary values of val.