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- *DECK GAMR
- FUNCTION GAMR (X)
- C***BEGIN PROLOGUE GAMR
- C***PURPOSE Compute the reciprocal of the Gamma function.
- C***LIBRARY SLATEC (FNLIB)
- C***CATEGORY C7A
- C***TYPE SINGLE PRECISION (GAMR-S, DGAMR-D, CGAMR-C)
- C***KEYWORDS FNLIB, RECIPROCAL GAMMA FUNCTION, SPECIAL FUNCTIONS
- C***AUTHOR Fullerton, W., (LANL)
- C***DESCRIPTION
- C
- C GAMR is a single precision function that evaluates the reciprocal
- C of the gamma function for single precision argument X.
- C
- C***REFERENCES (NONE)
- C***ROUTINES CALLED ALGAMS, GAMMA, XERCLR, XGETF, XSETF
- C***REVISION HISTORY (YYMMDD)
- C 770701 DATE WRITTEN
- C 861211 REVISION DATE from Version 3.2
- C 891214 Prologue converted to Version 4.0 format. (BAB)
- C 900727 Added EXTERNAL statement. (WRB)
- C***END PROLOGUE GAMR
- EXTERNAL GAMMA
- C***FIRST EXECUTABLE STATEMENT GAMR
- GAMR = 0.0
- IF (X.LE.0.0 .AND. AINT(X).EQ.X) RETURN
- C
- CALL XGETF (IROLD)
- CALL XSETF (1)
- IF (ABS(X).GT.10.0) GO TO 10
- GAMR = 1.0/GAMMA(X)
- CALL XERCLR
- CALL XSETF (IROLD)
- RETURN
- C
- 10 CALL ALGAMS (X, ALNGX, SGNGX)
- CALL XERCLR
- CALL XSETF (IROLD)
- GAMR = SGNGX * EXP(-ALNGX)
- RETURN
- C
- END
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