2.1.18.18 ocmath_tps_eval

Description

This function evaluate the value of given points using thin plate spline method.

Syntax

int ocmath_tps_eval( int np, const double * px, const double * py, double * pz, ocmath_strTPS * strTPS, bool bExtrapolation = true, double dNAN = NANUM, double dTol = 1E-3 )

Parameters

np

[input] the number of points to evaluate.

px

[input] arrays contain the x coordinates of the interpolation points.

py

[input] arrays contain the y coordinates of the interpolation points.

pz

[output] the interpolant value of the given points.

strTPS

[input] the structure contains the thin plate spline interpolation coefficients.

bExtrapolation

[input] the function will perform extrapolation on the points outside of the data hull if bExtrapolation = TRUE; or assign dNAN to all the outside poins if bExtrapolation = FALSE;

dNAN

[Input] the outside points will be set to dNAN if bExtrapolation = false. It is ignored when bExtrapolation = true.

dTol

[input] If bExtrapolation = false, the polygon that outline the margin of scatter data points will be inflated by dTol. This tolerence value is useful when the margin of scatter is a straight line but some points deviate by a small amout.

Return

OE_NOERROR for successful or

OE_TPS_FIT for error caused by ocmath_tps_fit or

OE_NULL_POINTER if pointer is null.

Examples

EX1

#include <wks2mat.h>
int ocmath_tps_eval_ex1()
{
	double			vX[]={1,2,3,4,5,6,7,8};
	double			vY[]={8,7,6,5,4,3,2,1};
	double			vZ[]={2,8,2,8,2,8,2,8};
	int				nPoints = 8;
	double			dRegularization,dSmooth  = 0;
	double			dx,dy,dz;
	int				nSamp = 6;
	const double	fInv = 1.0/(double)nSamp;
	ocmath_strTPS strTPS;
	ocmath_tps_initial(&strTPS);
	int nRet = ocmath_tps_fit(nPoints,vX,vY,vZ,dSmooth,&strTPS,&dRegularization);
	if(nRet <0)
		return 0;

	for(int jj = 0;jj<= nSamp; jj++ )
	{
		dy = fInv*jj;
		for(int ii = 0; ii<= nSamp; ii++)
		{
			dx = fInv*ii;
			if(ocmath_tps_eval(1,&dx,&dy,&dz,&strTPS) < 0)
				return 0;
			else
				printf("%9.6f\t",dz);
		}
		printf("\n");
	}
	
	return 1;
}

Remark

See Also

ocmath_tps_fit

Header to Include

wks2mat.h

Reference