besk0.f

      FUNCTION BESK0 (X)
C***BEGIN PROLOGUE  BESK0
C***PURPOSE  Compute the modified (hyperbolic) Bessel function of the
C            third kind of order zero.
C***LIBRARY   SLATEC (FNLIB)
C***CATEGORY  C10B1
C***TYPE      SINGLE PRECISION (BESK0-S, DBESK0-D)
C***KEYWORDS  FNLIB, HYPERBOLIC BESSEL FUNCTION,
C             MODIFIED BESSEL FUNCTION, ORDER ZERO, SPECIAL FUNCTIONS,
C             THIRD KIND
C***AUTHOR  Fullerton, W., (LANL)
C***DESCRIPTION
C
C BESK0(X) calculates the modified (hyperbolic) Bessel function
C of the third kind of order zero for real argument X .GT. 0.0.
C
C Series for BK0        on the interval  0.          to  4.00000D+00
C                                        with weighted error   3.57E-19
C                                         log weighted error  18.45
C                               significant figures required  17.99
C                                    decimal places required  18.97
C
C***REFERENCES  (NONE)
C***ROUTINES CALLED  BESI0, BESK0E, CSEVL, INITS, R1MACH, XERMSG
C***REVISION HISTORY  (YYMMDD)
C   770401  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   900326  Removed duplicate information from DESCRIPTION section.
C           (WRB)
C***END PROLOGUE  BESK0