slatec-bessel-cpp/f2c/zbunk.cpp

/* zbunk.f -- translated by f2c (version 20100827).
   This file no longer depends on f2c.
*/

#include "slatec-internal.hpp"

int zbunk_(double *zr, double *zi, double const *fnu,
	integer const *kode, integer *mr, integer const *n, double *yr, double *
	yi, integer *nz, double *tol, double *elim, double *alim)
{
    double ax, ay;

/* ***BEGIN PROLOGUE  ZBUNK */
/* ***SUBSIDIARY */
/* ***PURPOSE  Subsidiary to ZBESH and ZBESK */
/* ***LIBRARY   SLATEC */
/* ***TYPE      ALL (CBUNI-A, ZBUNI-A) */
/* ***AUTHOR  Amos, D. E., (SNL) */
/* ***DESCRIPTION */

/*     ZBUNK COMPUTES THE K BESSEL FUNCTION FOR FNU.GT.FNUL. */
/*     ACCORDING TO THE UNIFORM ASYMPTOTIC EXPANSION FOR K(FNU,Z) */
/*     IN ZUNK1 AND THE EXPANSION FOR H(2,FNU,Z) IN ZUNK2 */

/* ***SEE ALSO  ZBESH, ZBESK */
/* ***ROUTINES CALLED  ZUNK1, ZUNK2 */
/* ***REVISION HISTORY  (YYMMDD) */
/*   830501  DATE WRITTEN */
/*   910415  Prologue converted to Version 4.0 format.  (BAB) */
/* ***END PROLOGUE  ZBUNK */
/*     COMPLEX Y,Z */
/* ***FIRST EXECUTABLE STATEMENT  ZBUNK */
    /* Parameter adjustments */
    --yi;
    --yr;

    /* Function Body */
    *nz = 0;
    ax = abs(*zr) * 1.7321;
    ay = abs(*zi);
    if (ay > ax) {
	goto L10;
    }
/* ----------------------------------------------------------------------- */
/*     ASYMPTOTIC EXPANSION FOR K(FNU,Z) FOR LARGE FNU APPLIED IN */
/*     -PI/3.LE.ARG(Z).LE.PI/3 */
/* ----------------------------------------------------------------------- */
    zunk1_(zr, zi, fnu, kode, mr, n, &yr[1], &yi[1], nz, tol, elim, alim);
    goto L20;
L10:
/* ----------------------------------------------------------------------- */
/*     ASYMPTOTIC EXPANSION FOR H(2,FNU,Z*EXP(M*HPI)) FOR LARGE FNU */
/*     APPLIED IN PI/3.LT.ABS(ARG(Z)).LE.PI/2 WHERE M=+I OR -I */
/*     AND HPI=PI/2 */
/* ----------------------------------------------------------------------- */
    zunk2_(zr, zi, fnu, kode, mr, n, &yr[1], &yi[1], nz, tol, elim, alim);
L20:
    return 0;
} /* zbunk_ */