besi1e.f
FUNCTION BESI1E (X)
C***BEGIN PROLOGUE BESI1E
C***PURPOSE Compute the exponentially scaled modified (hyperbolic)
C Bessel function of the first kind of order one.
C***LIBRARY SLATEC (FNLIB)
C***CATEGORY C10B1
C***TYPE SINGLE PRECISION (BESI1E-S, DBSI1E-D)
C***KEYWORDS EXPONENTIALLY SCALED, FIRST KIND, FNLIB,
C HYPERBOLIC BESSEL FUNCTION, MODIFIED BESSEL FUNCTION,
C ORDER ONE, SPECIAL FUNCTIONS
C***AUTHOR Fullerton, W., (LANL)
C***DESCRIPTION
C
C BESI1E(X) calculates the exponentially scaled modified (hyperbolic)
C Bessel function of the first kind of order one for real argument X;
C i.e., EXP(-ABS(X))*I1(X).
C
C Series for BI1 on the interval 0. to 9.00000D+00
C with weighted error 2.40E-17
C log weighted error 16.62
C significant figures required 16.23
C decimal places required 17.14
C
C Series for AI1 on the interval 1.25000D-01 to 3.33333D-01
C with weighted error 6.98E-17
C log weighted error 16.16
C significant figures required 14.53
C decimal places required 16.82
C
C Series for AI12 on the interval 0. to 1.25000D-01
C with weighted error 3.55E-17
C log weighted error 16.45
C significant figures required 14.69
C decimal places required 17.12
C
C***REFERENCES (NONE)
C***ROUTINES CALLED CSEVL, INITS, R1MACH, XERMSG
C***REVISION HISTORY (YYMMDD)
C 770401 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 920618 Removed space from variable names. (RWC, WRB)
C***END PROLOGUE BESI1E