SLATEC Routines --- DASYJY ---

*DECK DASYJY
      SUBROUTINE DASYJY (FUNJY, X, FNU, FLGJY, IN, Y, WK, IFLW)
C***BEGIN PROLOGUE  DASYJY
C***SUBSIDIARY
C***PURPOSE  Subsidiary to DBESJ and DBESY
C***LIBRARY   SLATEC
C***TYPE      DOUBLE PRECISION (ASYJY-S, DASYJY-D)
C***AUTHOR  Amos, D. E., (SNLA)
C***DESCRIPTION
C
C                 DASYJY computes Bessel functions J and Y
C               for arguments X.GT.0.0 and orders FNU .GE. 35.0
C               on FLGJY = 1 and FLGJY = -1 respectively
C
C                                  INPUT
C
C      FUNJY - External subroutine JAIRY or YAIRY
C          X - Argument, X.GT.0.0D0
C        FNU - Order of the first Bessel function
C      FLGJY - Selection flag
C              FLGJY =  1.0D0 gives the J function
C              FLGJY = -1.0D0 gives the Y function
C         IN - Number of functions desired, IN = 1 or 2
C
C                                  OUTPUT
C
C         Y  - A vector whose first IN components contain the sequence
C       IFLW - A flag indicating underflow or overflow
C                    return variables for BESJ only
C      WK(1) = 1 - (X/FNU)**2 = W**2
C      WK(2) = SQRT(ABS(WK(1)))
C      WK(3) = ABS(WK(2) - ATAN(WK(2)))  or
C              ABS(LN((1 + WK(2))/(X/FNU)) - WK(2))
C            = ABS((2/3)*ZETA**(3/2))
C      WK(4) = FNU*WK(3)
C      WK(5) = (1.5*WK(3)*FNU)**(1/3) = SQRT(ZETA)*FNU**(1/3)
C      WK(6) = SIGN(1.,W**2)*WK(5)**2 = SIGN(1.,W**2)*ZETA*FNU**(2/3)
C      WK(7) = FNU**(1/3)
C
C     Abstract   **** A Double Precision Routine ****
C         DASYJY implements the uniform asymptotic expansion of
C         the J and Y Bessel functions for FNU.GE.35 and real
C         X.GT.0.0D0. The forms are identical except for a change
C         in sign of some of the terms. This change in sign is
C         accomplished by means of the flag FLGJY = 1 or -1. On
C         FLGJY = 1 the Airy functions AI(X) and DAI(X) are
C         supplied by the external function JAIRY, and on
C         FLGJY = -1 the Airy functions BI(X) and DBI(X) are
C         supplied by the external function YAIRY.
C
C***SEE ALSO  DBESJ, DBESY
C***ROUTINES CALLED  D1MACH, I1MACH
C***REVISION HISTORY  (YYMMDD)
C   750101  DATE WRITTEN
C   890531  Changed all specific intrinsics to generic.  (WRB)
C   890911  Removed unnecessary intrinsics.  (WRB)
C   891004  Correction computation of ELIM.  (WRB)
C   891009  Removed unreferenced variable.  (WRB)
C   891214  Prologue converted to Version 4.0 format.  (BAB)
C   900328  Added TYPE section.  (WRB)
C   910408  Updated the AUTHOR section.  (WRB)
C***END PROLOGUE  DASYJY