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git-svn-id: http://svn.osgeo.org/metacrs/proj/trunk@776 4e78687f-474d-0410-85f9-8d5e500ac6b2

1 files changed, 49 insertions, 0 deletions

diff --git a/src/pj_zpoly1.c b/src/pj_zpoly1.c
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--- /dev/null
+++ b/src/pj_zpoly1.c
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+/* evaluate complex polynomial */
+#ifndef lint
+static const char SCCSID[]="@(#)pj_zpoly1.c	4.3	93/06/12	GIE	REL";
+#endif
+#include <projects.h>
+/* note: coefficients are always from C_1 to C_n
+**	i.e. C_0 == (0., 0)
+**	n should always be >= 1 though no checks are made
+*/
+	COMPLEX
+pj_zpoly1(COMPLEX z, COMPLEX *C, int n) {
+	COMPLEX a;
+	double t;
+
+	a = *(C += n);
+	while (n-- > 0) {
+		a.r = (--C)->r + z.r * (t = a.r) - z.i * a.i;
+		a.i = C->i + z.r * a.i + z.i * t;
+	}
+	a.r = z.r * (t = a.r) - z.i * a.i;
+	a.i = z.r * a.i + z.i * t;
+	return a;
+}
+/* evaluate complex polynomial and derivative */
+	COMPLEX
+pj_zpolyd1(COMPLEX z, COMPLEX *C, int n, COMPLEX *der) {
+	COMPLEX a, b;
+	double t;
+	int first = 1;
+
+	a = *(C += n);
+	while (n-- > 0) {
+		if (first) {
+			first = 0;
+			b = a;
+		} else {
+			b.r = a.r + z.r * (t = b.r) - z.i * b.i;
+			b.i = a.i + z.r * b.i + z.i * t;
+		}
+		a.r = (--C)->r + z.r * (t = a.r) - z.i * a.i;
+		a.i = C->i + z.r * a.i + z.i * t;
+	}
+	b.r = a.r + z.r * (t = b.r) - z.i * b.i;
+	b.i = a.i + z.r * b.i + z.i * t;
+	a.r = z.r * (t = a.r) - z.i * a.i;
+	a.i = z.r * a.i + z.i * t;
+	*der = b;
+	return a;
+}