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root/Development/ray/src/common/tcos.c

Comparing ray/src/common/tcos.c (file contents):
Revision 3.6 by greg, Thu Jan 17 22:48:21 2013 UTC vs.
Revision 3.7 by greg, Thu Feb 7 20:19:52 2013 UTC

#	Line 50 | Line 50 | tcos(double x)                         /* approximate cosine */
50		}
51		return(0.);             /* should never be reached */
52		}
53	+
54	+
55	+	/* Fast arctangent approximation due to Rajan et al. 2006 */
56	+	double
57	+	aatan2(double y, double x)
58	+	{
59	+	double  ratio, aratio, val;
60	+
61	+	if (x == 0)
62	+	return (y > 0) ? PI/2. : 3./2.*PI;
63	+
64	+	aratio = (ratio = y/x) >= 0 ? ratio : -ratio;
65	+
66	+	if (aratio > 1.01)
67	+	return PI/2. - aatan2(x, y);
68	+
69	+	val = PI/4.*ratio - ratio*(aratio - 1.)*(0.2447 + 0.0663*aratio);
70	+
71	+	return val + PI*(x < 0);
72	+	}

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