 
      DOUBLE PRECISION FUNCTION DBSI0E(X)
C***BEGIN PROLOGUE  DBSI0E
C***DATE WRITTEN   770701   (YYMMDD)
C***REVISION DATE  820801   (YYMMDD)
C***CATEGORY NO.  C10B1
C***KEYWORDS  BESSEL FUNCTION,DOUBLE PRECISION,EXPONENTIALLY SCALED,
C             FIRST KIND,MODIFIED BESSEL FUNCTION,ORDER ZERO,
C             SPECIAL FUNCTION
C***AUTHOR  FULLERTON, W., (LANL)
C***PURPOSE  Computes the d.p. exponentially scaled hyperbolic Bessel
C            function of the first kind of order zero.
C***DESCRIPTION
C
C DBSI0E(X) calculates the double precision exponentially scaled
C modified (hyperbolic) Bessel function of the first kind of order
C zero for double precision argument X.  The result is the Bessel
C function I0(X) multiplied by EXP(-ABS(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 Series for AI0        on the interval  1.25000E-01 to  3.33333E-01
C                                        with weighted error   2.74E-32
C                                         log weighted error  31.56
C                               significant figures required  30.15
C                                    decimal places required  32.39
C
C Series for AI02       on the interval  0.          to  1.25000E-01
C                                        with weighted error   1.97E-32
C                                         log weighted error  31.71
C                               significant figures required  30.15
C                                    decimal places required  32.63
C***REFERENCES  (NONE)
C***ROUTINES CALLED  D1MACH,DCSEVL,INITDS
C***END PROLOGUE  DBSI0E
 
 
