add numerical recipes library

lib/nr/ansi/examples/xlinmin.c

@@ -0,0 +1,48 @@
+
+/* Driver for routine linmin */
+
+#include <stdio.h>
+#include <math.h>
+#define NRANSI
+#include "nr.h"
+#include "nrutil.h"
+
+#define NDIM 3
+#define PIO2 1.5707963
+
+float func(float x[])
+{
+	int i;
+	float f=0.0;
+
+	for (i=1;i<=3;i++) f += (x[i]-1.0)*(x[i]-1.0);
+	return f;
+}
+
+int main(void)
+{
+	int i,j;
+	float fret,sr2,x,*p,*xi;
+
+	p=vector(1,NDIM);
+	xi=vector(1,NDIM);
+	printf("\nMinimum of a 3-d quadratic centered\n");
+	printf("at (1.0,1.0,1.0). Minimum is found\n");
+	printf("along a series of radials.\n\n");
+	printf("%9s %12s %12s %14s \n","x","y","z","minimum");
+	for (i=0;i<=10;i++) {
+		x=PIO2*i/10.0;
+		sr2=sqrt(2.0);
+		xi[1]=sr2*cos(x);
+		xi[2]=sr2*sin(x);
+		xi[3]=1.0;
+		p[1]=p[2]=p[3]=0.0;
+		linmin(p,xi,NDIM,&fret,func);
+		for (j=1;j<=3;j++) printf("%12.6f ",p[j]);
+		printf("%12.6f\n",fret);
+	}
+	free_vector(xi,1,NDIM);
+	free_vector(p,1,NDIM);
+	return 0;
+}
+#undef NRANSI