 
      FUNCTION BESK1(X)
C***BEGIN PROLOGUE  BESK1
C***DATE WRITTEN   770401   (YYMMDD)
C***REVISION DATE  820801   (YYMMDD)
C***CATEGORY NO.  C10B1
C***KEYWORDS  BESSEL FUNCTION,HYPERBOLIC BESSEL FUNCTION,
C             MODIFIED BESSEL FUNCTION,ORDER ONE,THIRD KIND
C***AUTHOR  FULLERTON, W., (LANL)
C***PURPOSE  Computes the hyperbolic Bessel function of the third kind
C            of order one
C***DESCRIPTION
C
C BESK1(X) computes the modified (hyperbolic) Bessel function of third
C kind of order one for real argument X, where X .GT. 0.
C
C Series for BK1        on the interval  0.          to  4.00000D+00
C                                        with weighted error   7.02E-18
C                                         log weighted error  17.15
C                               significant figures required  16.73
C                                    decimal places required  17.67
C***REFERENCES  (NONE)
C***ROUTINES CALLED  BESI1,BESK1E,CSEVL,INITS,R1MACH,XERROR
C***END PROLOGUE  BESK1
 
 
