*DECK BESKS SUBROUTINE BESKS (XNU, X, NIN, BK) C***BEGIN PROLOGUE BESKS C***PURPOSE Compute a sequence of modified Bessel functions of the C third kind of fractional order. C***LIBRARY SLATEC (FNLIB) C***CATEGORY C10B3 C***TYPE SINGLE PRECISION (BESKS-S, DBESKS-D) C***KEYWORDS FNLIB, FRACTIONAL ORDER, MODIFIED BESSEL FUNCTION, C SEQUENCE OF BESSEL FUNCTIONS, SPECIAL FUNCTIONS, C THIRD KIND C***AUTHOR Fullerton, W., (LANL) C***DESCRIPTION C C BESKS computes a sequence of modified Bessel functions of the third C kind of order XNU + I at X, where X .GT. 0, XNU lies in (-1,1), C and I = 0, 1, ... , NIN - 1, if NIN is positive and I = 0, 1, ... , C NIN + 1, if NIN is negative. On return, the vector BK(.) Contains C the results at X for order starting at XNU. C C***REFERENCES (NONE) C***ROUTINES CALLED BESKES, R1MACH, XERMSG C***REVISION HISTORY (YYMMDD) C 770601 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 BESKS DIMENSION BK(*) SAVE XMAX DATA XMAX / 0.0 / C***FIRST EXECUTABLE STATEMENT BESKS IF (XMAX.EQ.0.0) XMAX = -LOG (R1MACH(1)) C IF (X .GT. XMAX) CALL XERMSG ('SLATEC', 'BESKS', + 'X SO BIG BESSEL K UNDERFLOWS', 1, 2) C CALL BESKES (XNU, X, NIN, BK) C EXPXI = EXP (-X) N = ABS (NIN) DO 20 I=1,N BK(I) = EXPXI * BK(I) 20 CONTINUE C RETURN END