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- *DECK COSDG
- FUNCTION COSDG (X)
- C***BEGIN PROLOGUE COSDG
- C***PURPOSE Compute the cosine of an argument in degrees.
- C***LIBRARY SLATEC (FNLIB)
- C***CATEGORY C4A
- C***TYPE SINGLE PRECISION (COSDG-S, DCOSDG-D)
- C***KEYWORDS COSINE, DEGREES, ELEMENTARY FUNCTIONS, FNLIB,
- C TRIGONOMETRIC
- C***AUTHOR Fullerton, W., (LANL)
- C***DESCRIPTION
- C
- C COSDG(X) evaluates the cosine for real X in degrees.
- C
- C***REFERENCES (NONE)
- C***ROUTINES CALLED (NONE)
- C***REVISION HISTORY (YYMMDD)
- C 770601 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 COSDG
- C JUNE 1977 EDITION. W. FULLERTON, C3, LOS ALAMOS SCIENTIFIC LAB.
- SAVE RADDEG
- DATA RADDEG / .017453292519943296E0 /
- C
- C***FIRST EXECUTABLE STATEMENT COSDG
- COSDG = COS (RADDEG*X)
- C
- IF (MOD(X,90.).NE.0.) RETURN
- N = ABS(X)/90.0 + 0.5
- N = MOD (N, 2)
- IF (N.EQ.0) COSDG = SIGN (1.0, COSDG)
- IF (N.EQ.1) COSDG = 0.0
- C
- RETURN
- END
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