1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
|
*DECK DLGAMS
SUBROUTINE DLGAMS (X, DLGAM, SGNGAM)
C***BEGIN PROLOGUE DLGAMS
C***PURPOSE Compute the logarithm of the absolute value of the Gamma
C function.
C***LIBRARY SLATEC (FNLIB)
C***CATEGORY C7A
C***TYPE DOUBLE PRECISION (ALGAMS-S, DLGAMS-D)
C***KEYWORDS ABSOLUTE VALUE OF THE LOGARITHM OF THE GAMMA FUNCTION,
C FNLIB, SPECIAL FUNCTIONS
C***AUTHOR Fullerton, W., (LANL)
C***DESCRIPTION
C
C DLGAMS(X,DLGAM,SGNGAM) calculates the double precision natural
C logarithm of the absolute value of the Gamma function for
C double precision argument X and stores the result in double
C precision argument DLGAM.
C
C***REFERENCES (NONE)
C***ROUTINES CALLED DLNGAM
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***END PROLOGUE DLGAMS
DOUBLE PRECISION X, DLGAM, SGNGAM, DLNGAM
C***FIRST EXECUTABLE STATEMENT DLGAMS
DLGAM = DLNGAM(X)
SGNGAM = 1.0D0
IF (X.GT.0.D0) RETURN
C
INT = MOD (-AINT(X), 2.0D0) + 0.1D0
IF (INT.EQ.0) SGNGAM = -1.0D0
C
RETURN
END
|
