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Viewing changes to routines/dcd/gamln1.f

  • Committer: Bazaar Package Importer
  • Author(s): Torsten Werner
  • Date: 2002-03-21 16:57:43 UTC
  • Revision ID: james.westby@ubuntu.com-20020321165743-e9mv12c1tb1plztg
Tags: upstream-2.6
Import upstream version 2.6

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routines/dcd/gamln1.f
 
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      DOUBLE PRECISION FUNCTION gamln1(a)
 
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C-----------------------------------------------------------------------
 
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C     EVALUATION OF LN(GAMMA(1 + A)) FOR -0.2 .LE. A .LE. 1.25
 
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C-----------------------------------------------------------------------
 
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C     .. Scalar Arguments ..
 
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      DOUBLE PRECISION a
 
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C     ..
 
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C     .. Local Scalars ..
 
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      DOUBLE PRECISION p0,p1,p2,p3,p4,p5,p6,q1,q2,q3,q4,q5,q6,r0,r1,r2,
 
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     +                 r3,r4,r5,s1,s2,s3,s4,s5,w,x
 
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C     ..
 
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C     .. Data statements ..
 
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C----------------------
 
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      DATA p0/.577215664901533D+00/,p1/.844203922187225D+00/,
 
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     +     p2/-.168860593646662D+00/,p3/-.780427615533591D+00/,
 
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     +     p4/-.402055799310489D+00/,p5/-.673562214325671D-01/,
 
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     +     p6/-.271935708322958D-02/
 
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      DATA q1/.288743195473681D+01/,q2/.312755088914843D+01/,
 
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     +     q3/.156875193295039D+01/,q4/.361951990101499D+00/,
 
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     +     q5/.325038868253937D-01/,q6/.667465618796164D-03/
 
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      DATA r0/.422784335098467D+00/,r1/.848044614534529D+00/,
 
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     +     r2/.565221050691933D+00/,r3/.156513060486551D+00/,
 
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     +     r4/.170502484022650D-01/,r5/.497958207639485D-03/
 
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      DATA s1/.124313399877507D+01/,s2/.548042109832463D+00/,
 
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     +     s3/.101552187439830D+00/,s4/.713309612391000D-02/,
 
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     +     s5/.116165475989616D-03/
 
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C     ..
 
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C     .. Executable Statements ..
 
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C----------------------
 
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      IF (a.GE.0.6D0) GO TO 10
 
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      w = ((((((p6*a+p5)*a+p4)*a+p3)*a+p2)*a+p1)*a+p0)/
 
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     +    ((((((q6*a+q5)*a+q4)*a+q3)*a+q2)*a+q1)*a+1.0D0)
 
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      gamln1 = -a*w
 
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      RETURN
 
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C
 
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   10 x = (a-0.5D0) - 0.5D0
 
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      w = (((((r5*x+r4)*x+r3)*x+r2)*x+r1)*x+r0)/
 
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     +    (((((s5*x+s4)*x+s3)*x+s2)*x+s1)*x+1.0D0)
 
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      gamln1 = x*w
 
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      RETURN
 
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      END