warptwin::InterpolateBilinear Class Reference

A class for performing simple x-y-z bilinear interpolation. More...

#include <InterpolateBilinear.h>

Public Member Functions
int	setData (const std::vector< double > &xValues, const std::vector< double > &yValues, const std::vector< std::vector< double > > &zValues)
	Sets the data for the interpolator.
int	getMinX (double &minX) const
	Returns the minimum x-value from the stored data.
int	getMaxX (double &maxX) const
	Returns the maximum x-value from the stored data.
int	getMinY (double &minX) const
	Returns the minimum y-value from the stored data.
int	getMaxY (double &maxX) const
	Returns the maximum y-value from the stored data.
int	interpolate (double x, double y, double &zInterpolated)
	Performs bilinear interpolation given an (x, y) value pair.

Detailed Description

A class for performing simple x-y-z bilinear interpolation.

This class allows you to store tabulated x, y, and z values, and then to compute interpolated z values for any (x, y) pair within the bounds of the stored data. The bilinear interpolation is performed between successive data points.

Methodology:

• Given two sets of points x[i], y[i] sorted by increasing x and y.
• To interpolate at a point pair (x', y'), find the four points: Q11 = (x1, y1) Q12 = (x1, y2) Q21 = (x2, y1) Q22 = (x2, y2) With known data points: z11 z12 z21 z22 such that: x1 <= x' < x2 and y1 <= y' < y2
• Then compute:

  

Error Handling:

• The class returns integer error codes rather than using exceptions.
  • 0 indicates success
  • Any non-zero integer indicates an error
• If interpolation is requested for (x, y) below the minimum x/y or above the maximum x/y, a non-zero error code is returned.

Author: James Tabony james.nosp@m..tab.nosp@m.ony@a.nosp@m.ttx..nosp@m.tech

Member Function Documentation

getMaxX()

int warptwin::InterpolateBilinear::getMaxX

(

double &

maxX

)

const

Returns the maximum x-value from the stored data.

Parameters

[out]

maxX

The maximum x-value will be written here if the function succeeds.

Returns

Integer error code (0 for success, non-zero for error).

This function returns an error if there is no data stored.

getMaxY()

int warptwin::InterpolateBilinear::getMaxY

(

double &

maxX

)

const

Returns the maximum y-value from the stored data.

Parameters

[out]

maxY

The maximum y-value will be written here if the function succeeds.

Returns

Integer error code (0 for success, non-zero for error).

This function returns an error if there is no data stored.

getMinX()

int warptwin::InterpolateBilinear::getMinX

(

double &

minX

)

const

Returns the minimum x-value from the stored data.

Parameters

[out]

minX

The minimum x-value will be written here if the function succeeds.

Returns

Integer error code (0 for success, non-zero for error).

This function returns an error if there is no data stored.

getMinY()

int warptwin::InterpolateBilinear::getMinY

(

double &

minX

)

const

Returns the minimum y-value from the stored data.

Parameters

[out]

minY

The minimum y-value will be written here if the function succeeds.

Returns

Integer error code (0 for success, non-zero for error).

This function returns an error if there is no data stored.

interpolate()

int warptwin::InterpolateBilinear::interpolate	(	double	x,
		double	y,
		double &	zInterpolated )

Performs bilinear interpolation given an (x, y) value pair.

Parameters

[in]	x	The x-value for which to interpolate.
[in]	y	The y-value for which to interpolate.
[out]	zInterpolated	The interpolated z-value will be written here if the function succeeds.

Returns

Integer error code (0 for success, non-zero for error).

If x or y is out of the bounds of the stored table, this function returns a non-zero error code. If there are not enough points to perform interpolation, it returns a non-zero error code as well.

setData()

int warptwin::InterpolateBilinear::setData	(	const std::vector< double > &	xValues,
		const std::vector< double > &	yValues,
		const std::vector< std::vector< double > > &	zValues )

Sets the data for the interpolator.

Parameters

xValues	A vector of x-values (must be sorted in ascending order).
yValues	A vector of y-values (must be sorted in ascending order).
zValues	A matrix of z-values whose ith row and jth col corresponds to the point x[i], y[j]

Returns

An integer error code (0 for success, non-zero for error).

This function replaces any previously stored data with the new x, y, and z values. It is required that xValues.size() == zValues.size() and yValues.size() == zValues[0].size(). It is alse required that xValues and yValues is sorted in ascending order. If these conditions are not met, a non-zero error code is returned.

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The documentation for this class was generated from the following files:

• /Users/mickey/Documents/Projects/warptwin/cpp/src/utils/InterpolateBilinear.h
• /Users/mickey/Documents/Projects/warptwin/cpp/src/utils/InterpolateBilinear.cpp