# besj1.f

          FUNCTION BESJ1 (X)
    C***BEGIN PROLOGUE  BESJ1
    C***PURPOSE  Compute the Bessel function of the first kind of order one.
    C***LIBRARY   SLATEC (FNLIB)
    C***CATEGORY  C10A1
    C***TYPE      SINGLE PRECISION (BESJ1-S, DBESJ1-D)
    C***KEYWORDS  BESSEL FUNCTION, FIRST KIND, FNLIB, ORDER ONE,
    C             SPECIAL FUNCTIONS
    C***AUTHOR  Fullerton, W., (LANL)
    C***DESCRIPTION
    C
    C BESJ1(X) calculates the Bessel function of the first kind of
    C order one for real argument X.
    C
    C Series for BJ1        on the interval  0.          to  1.60000D+01
    C                                        with weighted error   4.48E-17
    C                                         log weighted error  16.35
    C                               significant figures required  15.77
    C                                    decimal places required  16.89
    C
    C Series for BM1        on the interval  0.          to  6.25000D-02
    C                                        with weighted error   5.61E-17
    C                                         log weighted error  16.25
    C                               significant figures required  14.97
    C                                    decimal places required  16.91
    C
    C Series for BTH1       on the interval  0.          to  6.25000D-02
    C                                        with weighted error   4.10E-17
    C                                         log weighted error  16.39
    C                               significant figures required  15.96
    C                                    decimal places required  17.08
    C
    C***REFERENCES  (NONE)
    C***ROUTINES CALLED  CSEVL, INITS, R1MACH, XERMSG
    C***REVISION HISTORY  (YYMMDD)
    C   780601  DATE WRITTEN
    C   890210  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   900326  Removed duplicate information from DESCRIPTION section.
    C           (WRB)
    C***END PROLOGUE  BESJ1