cbunk.f

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      SUBROUTINE cbunk(Z, FNU, KODE, MR, N, Y, NZ, TOL, ELIM, ALIM)
C***BEGIN PROLOGUE  CBUNK
C***REFER TO  CBESK,CBESH
C
C     CBUNK COMPUTES THE K BESSEL FUNCTION FOR FNU.GT.FNUL.
C     ACCORDING TO THE UNIFORM ASYMPTOTIC EXPANSION FOR K(FNU,Z)
C     IN CUNK1 AND THE EXPANSION FOR H(2,FNU,Z) IN CUNK2
C
C***ROUTINES CALLED  CUNK1,CUNK2
C***END PROLOGUE  CBUNK
      COMPLEX y, z
      REAL alim, ax, ay, elim, fnu, tol, xx, yy
      INTEGER kode, mr, n, nz
      dimension y(n)
      nz = 0
      xx = REAL(z)
      yy = aimag(z)
      ax = abs(xx)*1.7321e0
      ay = abs(yy)
      IF (ay.GT.ax) go to 10
C-----------------------------------------------------------------------
C     ASYMPTOTIC EXPANSION FOR K(FNU,Z) FOR LARGE FNU APPLIED IN
C     -PI/3.LE.ARG(Z).LE.PI/3
C-----------------------------------------------------------------------
      CALL cunk1(z, fnu, kode, mr, n, y, nz, tol, elim, alim)
      go to 20
   10 CONTINUE
C-----------------------------------------------------------------------
C     ASYMPTOTIC EXPANSION FOR H(2,FNU,Z*EXP(M*HPI)) FOR LARGE FNU
C     APPLIED IN PI/3.LT.ABS(ARG(Z)).LE.PI/2 WHERE M=+I OR -I
C     AND HPI=PI/2
C-----------------------------------------------------------------------
      CALL cunk2(z, fnu, kode, mr, n, y, nz, tol, elim, alim)
   20 CONTINUE
      RETURN
      END