add numerical recipes library

lib/nr/ansi/examples/xddpoly.c

@@ -0,0 +1,45 @@
+
+/* Driver for routine ddpoly */
+
+#include <stdio.h>
+#define NRANSI
+#include "nr.h"
+#include "nrutil.h"
+
+#define NC 5
+#define ND NC-1
+#define NP 20
+
+int main(void)
+{
+	int i,j,k;
+	float x,pwr,*pd,**d;
+	static float c[NC+1]={-1.0,5.0,-10.0,10.0,-5.0,1.0};
+	static char *a[ND+1]={"polynomial:", "first deriv:",
+		"second deriv:","third deriv:","fourth deriv:"};
+
+	pd=vector(0,ND);
+	d=matrix(0,ND,1,NP);
+	for (i=1;i<=NP;i++) {
+		x=0.1*i;
+		ddpoly(c,NC,x,pd,ND);
+		for (j=0;j<=ND;j++) d[j][i]=pd[j];
+	}
+	for (i=0;i<=ND;i++) {
+		printf("%6s %s \n"," ",a[i]);
+		printf("%12s %17s %15s\n","x","DDPOLY","actual");
+		for (j=1;j<=NP;j++) {
+			x=0.1*j;
+			pwr=1.0;
+			for (k=1;k<=NC-i;k++) pwr *= x-1.0;
+			printf("%15.6f %15.6f %15.6f\n",x,d[i][j],
+				(factrl(NC)/factrl(NC-i))*pwr);
+		}
+		printf("press ENTER to continue...\n");
+		(void) getchar();
+	}
+	free_matrix(d,0,ND,1,NP);
+	free_vector(pd,0,ND);
+	return 0;
+}
+#undef NRANSI