SLATEC Routines --- DBESI0 ---

*DECK DBESI0
      DOUBLE PRECISION FUNCTION DBESI0 (X)
C***BEGIN PROLOGUE  DBESI0
C***PURPOSE  Compute the hyperbolic Bessel function of the first kind
C            of order zero.
C***LIBRARY   SLATEC (FNLIB)
C***CATEGORY  C10B1
C***TYPE      DOUBLE PRECISION (BESI0-S, DBESI0-D)
C***KEYWORDS  FIRST KIND, FNLIB, HYPERBOLIC BESSEL FUNCTION,
C             MODIFIED BESSEL FUNCTION, ORDER ZERO, SPECIAL FUNCTIONS
C***AUTHOR  Fullerton, W., (LANL)
C***DESCRIPTION
C
C DBESI0(X) calculates the double precision modified (hyperbolic)
C Bessel function of the first kind of order zero and double
C precision argument X.
C
C Series for BI0        on the interval  0.          to  9.00000E+00
C                                        with weighted error   9.51E-34
C                                         log weighted error  33.02
C                               significant figures required  33.31
C                                    decimal places required  33.65
C
C***REFERENCES  (NONE)
C***ROUTINES CALLED  D1MACH, DBSI0E, DCSEVL, INITDS, XERMSG
C***REVISION HISTORY  (YYMMDD)
C   770701  DATE WRITTEN
C   890531  Changed all specific intrinsics to generic.  (WRB)
C   890531  REVISION DATE from Version 3.2
C   891214  Prologue converted to Version 4.0 format.  (BAB)
C   900315  CALLs to XERROR changed to CALLs to XERMSG.  (THJ)
C***END PROLOGUE  DBESI0