SLATEC Routines --- DBESI1 ---

*DECK DBESI1
      DOUBLE PRECISION FUNCTION DBESI1 (X)
C***BEGIN PROLOGUE  DBESI1
C***PURPOSE  Compute the modified (hyperbolic) Bessel function of the
C            first kind of order one.
C***LIBRARY   SLATEC (FNLIB)
C***CATEGORY  C10B1
C***TYPE      DOUBLE PRECISION (BESI1-S, DBESI1-D)
C***KEYWORDS  FIRST KIND, FNLIB, HYPERBOLIC BESSEL FUNCTION,
C             MODIFIED BESSEL FUNCTION, ORDER ONE, SPECIAL FUNCTIONS
C***AUTHOR  Fullerton, W., (LANL)
C***DESCRIPTION
C
C DBESI1(X) calculates the double precision modified (hyperbolic)
C Bessel function of the first kind of order one and double precision
C argument X.
C
C Series for BI1        on the interval  0.          to  9.00000E+00
C                                        with weighted error   1.44E-32
C                                         log weighted error  31.84
C                               significant figures required  31.45
C                                    decimal places required  32.46
C
C***REFERENCES  (NONE)
C***ROUTINES CALLED  D1MACH, DBSI1E, 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  DBESI1