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