# besi0e.f

          FUNCTION BESI0E (X)
    C***BEGIN PROLOGUE  BESI0E
    C***PURPOSE  Compute the exponentially scaled modified (hyperbolic)
    C            Bessel function of the first kind of order zero.
    C***LIBRARY   SLATEC (FNLIB)
    C***CATEGORY  C10B1
    C***TYPE      SINGLE PRECISION (BESI0E-S, DBSI0E-D)
    C***KEYWORDS  EXPONENTIALLY SCALED, FIRST KIND, FNLIB,
    C             HYPERBOLIC BESSEL FUNCTION, MODIFIED BESSEL FUNCTION,
    C             ORDER ZERO, SPECIAL FUNCTIONS
    C***AUTHOR  Fullerton, W., (LANL)
    C***DESCRIPTION
    C
    C BESI0E(X) calculates the exponentially scaled modified (hyperbolic)
    C Bessel function of the first kind of order zero for real argument X;
    C i.e., EXP(-ABS(X))*I0(X).
    C
    C
    C Series for BI0        on the interval  0.          to  9.00000D+00
    C                                        with weighted error   2.46E-18
    C                                         log weighted error  17.61
    C                               significant figures required  17.90
    C                                    decimal places required  18.15
    C
    C
    C Series for AI0        on the interval  1.25000D-01 to  3.33333D-01
    C                                        with weighted error   7.87E-17
    C                                         log weighted error  16.10
    C                               significant figures required  14.69
    C                                    decimal places required  16.76
    C
    C
    C Series for AI02       on the interval  0.          to  1.25000D-01
    C                                        with weighted error   3.79E-17
    C                                         log weighted error  16.42
    C                               significant figures required  14.86
    C                                    decimal places required  17.09
    C
    C***REFERENCES  (NONE)
    C***ROUTINES CALLED  CSEVL, INITS, R1MACH
    C***REVISION HISTORY  (YYMMDD)
    C   770701  DATE WRITTEN
    C   890313  REVISION DATE from Version 3.2
    C   891214  Prologue converted to Version 4.0 format.  (BAB)
    C***END PROLOGUE  BESI0E