add numerical recipes library

lib/nr/ansi/examples/xtoeplz.c

@@ -0,0 +1,32 @@
+
+/* Driver for routine toeplz */
+
+#include <stdio.h>
+#define NRANSI
+#include "nr.h"
+
+#define N 5
+#define TWON (2*N)
+
+int main(void)
+{
+	int i,j;
+	float sum,r[TWON+1],x[N+1],y[N+1];
+
+	for (i=1;i<=N;i++) y[i]=0.1*i;
+	for (i=1;i<TWON;i++) r[i]=1.0/i;
+	toeplz(r,x,y,N);
+	printf("Solution vector:\n");
+	for (i=1;i<=N;i++)
+		printf("%7s%1d%s %13f\n","x[",i,"] =",x[i]);
+	printf("\nTest of solution:\n");
+	printf("%13s %12s\n","mtrx*soln","original");
+	for (i=1;i<=N;i++) {
+		sum=0.0;
+		for (j=1;j<=N;j++)
+			sum += (r[N+i-j]*x[j]);
+		printf("%12.4f %12.4f\n",sum,y[i]);
+	}
+	return 0;
+}
+#undef NRANSI