kml_?_spline_eval_deriv2
Return the second-order derivative of the interpolation function at a given point (x). The interpolation object spline and accelerator xacc are used in the calculation. If x is outside the range of xarr, an error message is returned.
Interface Definition
int kml_float_spline_eval_deriv2_e(const kml_float_spline *spline, float x,
kml_spline_accel *a, float *d2)
float kml_float_spline_eval_deriv2(const kml_float_spline *spline, float x, kml_spline_accel *a)
int kml_double_spline_eval_deriv2_e(const kml_double_spline *spline, double x, kml_interp_accel *a, double *d2);
double kml_double_spline_eval_deriv2(const kml_double_spline *spline, double x, kml_interp_accel *a);
Parameters
Parameter |
Type |
Description |
Input/Output |
|---|---|---|---|
spline |
kml_float_spline*, kml_double_spline* |
Pointer to an interpolation object. |
Input |
x |
float, double |
Value of the solution point x. |
Input |
y |
float, double |
Value of the solution point y. |
Input |
a |
kml_spline_accel * |
Pointer to an accelerator object. |
Input |
Dependencies
#include "kipl.h"
Examples
const size_t xMin = 4;
const size_t xMax = 2048;
const size_t xSize = 4;
const float xValLo = 1;
const float xValHi = 2;
float xArr[4] = {1,1.33,1.67,2};
float* yArr = (float*)malloc(xSize * sizeof(float));
float x = 1;
float y = 0;
kml_float_spline *spline = kml_float_spline_alloc(kml_float_interp_cspline, xSize);
kml_interp_accel *xacc = kml_interp_accel_alloc();
kml_float_spline_init(spline, xSize, xArr, yArr);
y = kml_float_spline_eval_deriv2(spline, xArr, x, xacc);
kml_float_spline_free(spline);
kml_interp_accel_free(xacc);