1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
|
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <gsl/gsl_math.h>
#include <gsl/gsl_matrix.h>
#include <gsl/gsl_bspline.h>
int
main (void)
{
const size_t nbreak = 6;
const size_t spline_order = 4;
gsl_bspline_workspace *w = gsl_bspline_alloc(spline_order, nbreak);
const size_t p = gsl_bspline_ncontrol(w);
const size_t n = 300;
const double a = 0.0;
const double b = 1.0;
const double dx = (b - a) / (n - 1.0);
gsl_matrix *dB = gsl_matrix_alloc(p, spline_order);
size_t i, j, k;
/* uniform breakpoints on [a, b] */
gsl_bspline_init_uniform(a, b, w);
/* output knot vector */
gsl_vector_fprintf(stdout, w->knots, "%f");
printf("\n\n");
for (i = 0; i < spline_order; ++i)
{
for (j = 0; j < n; ++j)
{
double xj = j * dx;
gsl_bspline_eval_deriv_basis(xj, i, dB, w);
printf("%f ", xj);
for (k = 0; k < p; ++k)
printf("%f ", gsl_matrix_get(dB, k, i));
printf("\n");
}
printf("\n\n");
}
gsl_matrix_free(dB);
gsl_bspline_free(w);
return 0;
}
|
