ASYIK(3)

SYNOPSIS
SUBROUTINE ASYIK (X, FNU, KODE, FLGIK, RA, ARG, IN, Y)

NAME
asyik - Subsidiary to BESI and BESK

LIBRARY
SLATEC

TYPE
SINGLE PRECISION (ASYIK-S, DASYIK-D)

AUTHOR
Amos, D. E., (SNLA)

DESCRIPTION
ASYIK computes Bessel functions I and K for arguments X.GT.0.0 and orders FNU.GE.35 on FLGIK = 1 and FLGIK = -1 respectively. INPUT X - argument, X.GT.0.0E0 FNU - order of first Bessel function KODE - a parameter to indicate the scaling option KODE=1 returns Y(I)= I/SUB(FNU+I-1)/(X), I=1,IN or Y(I)= K/SUB(FNU+I-1)/(X), I=1,IN on FLGIK = 1.0E0 or FLGIK = -1.0E0 KODE=2 returns Y(I)=EXP(-X)*I/SUB(FNU+I-1)/(X), I=1,IN or Y(I)=EXP( X)*K/SUB(FNU+I-1)/(X), I=1,IN on FLGIK = 1.0E0 or FLGIK = -1.0E0 FLGIK - selection parameter for I or K function FLGIK = 1.0E0 gives the I function FLGIK = -1.0E0 gives the K function RA - SQRT(1.+Z*Z), Z=X/FNU ARG - argument of the leading exponential IN - number of functions desired, IN=1 or 2 OUTPUT Y - a vector whose first in components contain the sequence Abstract ASYIK implements the uniform asymptotic expansion of the I and K Bessel functions for FNU.GE.35 and real X.GT.0.0E0. The forms are identical except for a change in sign of some of the terms. This change in sign is accomplished by means of the flag FLGIK = 1 or -1.

SEE ALSO
BESI, BESK

ROUTINES CALLED
R1MACH

REVISION HISTORY (YYMMDD)
750101 DATE WRITTEN
890531 Changed all specific intrinsics to generic. (WRB)
891214 Prologue converted to Version 4.0 format. (BAB)
900328 Added TYPE section. (WRB)
910408 Updated the AUTHOR section. (WRB)