 
      FUNCTION GAMLN(X)
C
C     WRITTEN BY D. E. AMOS, SEPTEMBER, 1977.
C
C     REFERENCES
C         SAND-77-1518
C
C         COMPUTER APPROXIMATIONS BY J.F.HART, ET.AL., SIAM SERIES IN
C         APPLIED MATHEMATICS, WILEY, 1968, P.135-136.
C
C         NBS HANDBOOK OF MATHEMATICAL FUNCTIONS, AMS 55, BY
C         M. ABRAMOWITZ AND I.A. STEGUN, DECEMBER. 1955, P.257.
C
C     ABSTRACT
C         GAMLN COMPUTES THE NATURAL LOG OF THE GAMMA FUNCTION FOR
C         X.GT.0. A RATIONAL CHEBYSHEV APPROXIMATION IS USED ON
C         8.LT.X.LT.1000., THE ASYMPTOTIC EXPANSION FOR X.GE.1000. AND
C         A RATIONAL CHEBYSHEV APPROXIMATION ON 2.LT.X.LT.3. FOR
C         0.LT.X.LT.8. AND X NON-INTEGRAL, FORWARD OR BACKWARD
C         RECURSION FILLS IN THE INTERVALS  0.LT.X.LT.2 AND
C         3.LT.X.LT.8. FOR X=1.,2.,...,100., GAMLN IS SET TO
C         NATURAL LOGS OF FACTORIALS.
C
C     DESCRIPTION OF ARGUMENTS
C
C         INPUT
C           X      - X.GT.0
C
C         OUTPUT
C           GAMLN  - NATURAL LOG OF THE GAMMA FUNCTION AT X
C
C     ERROR CONDITIONS
C         IMPROPER INPUT ARGUMENT - A FATAL ERROR
C
C
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