Class BicubicInterpolatingFunction
java.lang.Object
org.apache.commons.math3.analysis.interpolation.BicubicInterpolatingFunction
- All Implemented Interfaces:
BivariateFunction
Function that implements the
bicubic spline interpolation.
- Since:
- 3.4
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Field Summary
FieldsModifier and TypeFieldDescriptionprivate static final double[][]
Matrix to compute the spline coefficients from the function values and function derivatives valuesprivate static final int
Number of coefficients.private final BicubicFunction[][]
Set of cubic splines patching the whole data gridprivate final double[]
Samples x-coordinatesprivate final double[]
Samples y-coordinates -
Constructor Summary
ConstructorsConstructorDescriptionBicubicInterpolatingFunction
(double[] x, double[] y, double[][] f, double[][] dFdX, double[][] dFdY, double[][] d2FdXdY) -
Method Summary
Modifier and TypeMethodDescriptionprivate double[]
computeSplineCoefficients
(double[] beta) Compute the spline coefficients from the list of function values and function partial derivatives values at the four corners of a grid element.boolean
isValidPoint
(double x, double y) Indicates whether a point is within the interpolation range.private int
searchIndex
(double c, double[] val) double
value
(double x, double y) Compute the value for the function.
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Field Details
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NUM_COEFF
private static final int NUM_COEFFNumber of coefficients.- See Also:
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AINV
private static final double[][] AINVMatrix to compute the spline coefficients from the function values and function derivatives values -
xval
private final double[] xvalSamples x-coordinates -
yval
private final double[] yvalSamples y-coordinates -
splines
Set of cubic splines patching the whole data grid
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Constructor Details
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BicubicInterpolatingFunction
public BicubicInterpolatingFunction(double[] x, double[] y, double[][] f, double[][] dFdX, double[][] dFdY, double[][] d2FdXdY) throws DimensionMismatchException, 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.dFdX
- Values of the partial derivative of function with respect to x on every grid point.dFdY
- Values of the partial derivative of function with respect to y on every grid point.d2FdXdY
- Values of the cross partial derivative of function on every grid point.- Throws:
DimensionMismatchException
- if the various arrays do not contain the expected number of elements.NonMonotonicSequenceException
- ifx
ory
are not strictly increasing.NoDataException
- if any of the arrays has zero length.
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Method Details
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value
Compute the value for the function.- Specified by:
value
in interfaceBivariateFunction
- 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
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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.
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searchIndex
private int searchIndex(double c, double[] val) - Parameters:
c
- Coordinate.val
- Coordinate samples.- Returns:
- the index in
val
corresponding to the interval containingc
. - Throws:
OutOfRangeException
- ifc
is out of the range defined by the boundary values ofval
.
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computeSplineCoefficients
private double[] computeSplineCoefficients(double[] beta) Compute the spline coefficients from the list of function values and function partial derivatives values at the four corners of a grid element. They must be specified in the following order:- f(0,0)
- f(1,0)
- f(0,1)
- f(1,1)
- fx(0,0)
- fx(1,0)
- fx(0,1)
- fx(1,1)
- fy(0,0)
- fy(1,0)
- fy(0,1)
- fy(1,1)
- fxy(0,0)
- fxy(1,0)
- fxy(0,1)
- fxy(1,1)
- Parameters:
beta
- List of function values and function partial derivatives values.- Returns:
- the spline coefficients.
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