dbsi1e.f
DOUBLE PRECISION FUNCTION DBSI1E (X)
C***BEGIN PROLOGUE DBSI1E
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 DOUBLE 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 DBSI1E(X) calculates the double precision exponentially scaled
C modified (hyperbolic) Bessel function of the first kind of order
C one for double precision argument X. The result is I1(X)
C multiplied by EXP(-ABS(X)).
C
C Series for BI1 on the interval 0. to 9.00000E+00
C with weighted error 1.44E-32
C log weighted error 31.84
C significant figures required 31.45
C decimal places required 32.46
C
C Series for AI1 on the interval 1.25000E-01 to 3.33333E-01
C with weighted error 2.81E-32
C log weighted error 31.55
C significant figures required 29.93
C decimal places required 32.38
C
C Series for AI12 on the interval 0. to 1.25000E-01
C with weighted error 1.83E-32
C log weighted error 31.74
C significant figures required 29.97
C decimal places required 32.66
C
C***REFERENCES (NONE)
C***ROUTINES CALLED D1MACH, DCSEVL, INITDS, XERMSG
C***REVISION HISTORY (YYMMDD)
C 770701 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***END PROLOGUE DBSI1E