add numerical recipes library

lib/nr/ansi/examples/xfixrts.c

@@ -0,0 +1,56 @@
+
+/* Driver for routine fixrts */
+
+#include <stdio.h>
+#define NRANSI
+#include "nr.h"
+#include "complex.h"
+
+#define NPOLES 6
+#define NP1 (NPOLES+1)
+#define ONE Complex(1.0,0.0)
+#define TRUE 1
+
+int main(void)
+{
+	int i,polish=TRUE;
+	static float d[NP1]=
+		{0.0,6.0,-15.0,20.0,-15.0,6.0,0.0};
+	fcomplex zcoef[NP1],zeros[NP1],z1,z2;
+
+	/* finding roots of (z-1.0)^6=1.0 */
+	/* first write roots */
+	zcoef[NPOLES]=ONE;
+	for (i=NPOLES-1;i>=0;i--)
+		zcoef[i] = Complex(-d[NPOLES-i],0.0);
+	zroots(zcoef,NPOLES,zeros,polish);
+	printf("Roots of (z-1.0)^6 = 1.0\n");
+	printf("%24s %27s \n","Root","(z-1.0)^6");
+	for (i=1;i<=NPOLES;i++) {
+		z1=Csub(zeros[i],ONE);
+		z2=Cmul(z1,z1);
+		z1=Cmul(z1,z2);
+		z1=Cmul(z1,z1);
+		printf("%6d %12.6f %12.6f %12.6f %12.6f\n",
+			i,zeros[i].r,zeros[i].i,z1.r,z1.i);
+	}
+	/* now fix them to lie within unit circle */
+	fixrts(d,NPOLES);
+	/* check results */
+	zcoef[NPOLES]=ONE;
+	for (i=NPOLES-1;i>=0;i--)
+		zcoef[i] = Complex(-d[NPOLES-i],0.0);
+	zroots(zcoef,NPOLES,zeros,polish);
+	printf("\nRoots reflected in unit circle\n");
+	printf("%24s %27s \n","Root","(z-1.0)^6");
+	for (i=1;i<=NPOLES;i++) {
+		z1=Csub(zeros[i],ONE);
+		z2=Cmul(z1,z1);
+		z1=Cmul(z1,z2);
+		z1=Cmul(z1,z1);
+		printf("%6d %12.6f %12.6f %12.6f %12.6f\n",
+			i,zeros[i].r,zeros[i].i,z1.r,z1.i);
+	}
+	return 0;
+}
+#undef NRANSI