# dbsi1e.f

          DOUBLE PRECISION FUNCTION DBSI1E (X)
    C***BEGIN PROLOGUE  DBSI1E
    C***PURPOSE  Compute the exponentially scaled modified (hyperbolic)
    C            Bessel function of the first kind of order one.
    C***LIBRARY   SLATEC (FNLIB)
    C***CATEGORY  C10B1
    C***TYPE      DOUBLE PRECISION (BESI1E-S, DBSI1E-D)
    C***KEYWORDS  EXPONENTIALLY SCALED, FIRST KIND, FNLIB,
    C             HYPERBOLIC BESSEL FUNCTION, MODIFIED BESSEL FUNCTION,
    C             ORDER ONE, SPECIAL FUNCTIONS
    C***AUTHOR  Fullerton, W., (LANL)
    C***DESCRIPTION
    C
    C DBSI1E(X) calculates the double precision exponentially scaled
    C modified (hyperbolic) Bessel function of the first kind of order
    C one for double precision argument X.  The result is I1(X)
    C multiplied by EXP(-ABS(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 Series for AI1        on the interval  1.25000E-01 to  3.33333E-01
    C                                        with weighted error   2.81E-32
    C                                         log weighted error  31.55
    C                               significant figures required  29.93
    C                                    decimal places required  32.38
    C
    C Series for AI12       on the interval  0.          to  1.25000E-01
    C                                        with weighted error   1.83E-32
    C                                         log weighted error  31.74
    C                               significant figures required  29.97
    C                                    decimal places required  32.66
    C
    C***REFERENCES  (NONE)
    C***ROUTINES CALLED  D1MACH, 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  DBSI1E