/* nag_specfun_bessel_zeros (s17alc) Example Program.
*
* Copyright 2024 Numerical Algorithms Group.
*
* NAG C Library
*
* Mark 30.1, 2024.
*
*/
#include <math.h>
#include <nag.h>
#include <stdio.h>
int main(void) {
#define NMAX 100
Integer exit_status = 0, i, mode, n;
NagError fail;
double a, rel, *x = 0;
INIT_FAIL(fail);
/* Skip heading in data file */
scanf("%*[^\n]");
printf("nag_specfun_bessel_zeros (s17alc) Example Program Results\n\n");
if (!(x = NAG_ALLOC(NMAX, double))) {
printf("Allocation failure\n");
exit_status = -1;
goto END;
}
/* nag_machine_precision (x02ajc).
* The machine precision
*/
rel = sqrt(nag_machine_precision);
scanf("%lf %" NAG_IFMT " %" NAG_IFMT "", &a, &n, &mode);
/* nag_specfun_bessel_zeros (s17alc).
* Zeros of Bessel functions J_alpha(x), (J_alpha')(x),
* Y_alpha(x) or (Y_alpha')(x)
*/
nag_specfun_bessel_zeros(a, n, mode, rel, x, &fail);
if (fail.code == NE_NOERROR) {
printf(" a n mode\n");
printf(" %4.1f%3" NAG_IFMT "%6" NAG_IFMT "\n\n", a, n, mode);
if (mode == 1)
printf("Leading n positive zeros of J\n");
else if (mode == 2)
printf("Leading n positive zeros of Y\n");
else if (mode == 3) {
if (a == 0.0)
printf("Leading n non-negative zeros of J'\n");
else
printf("Leading n positive zeros of J'\n");
} else if (mode == 4)
printf("Leading n positive zeros of Y'\n\n");
for (i = 0; i <= n - 1; ++i)
printf(" x = %13.4e\n", x[i]);
printf("\n");
} else {
printf("Error from nag_specfun_bessel_zeros (s17alc).\n%s\n", fail.message);
exit_status = 1;
goto END;
}
END:
NAG_FREE(x);
return exit_status;
}