add numerical recipes library

lib/nr/ansi/examples/xamoeba.c

@@ -0,0 +1,49 @@
+
+/* Driver for routine amoeba */
+
+#include <stdio.h>
+#include <math.h>
+#define NRANSI
+#include "nr.h"
+#include "nrutil.h"
+
+#define MP 4
+#define NP 3
+#define FTOL 1.0e-6
+
+float func(float x[])
+{
+	return 0.6-bessj0(SQR(x[1]-0.5)+SQR(x[2]-0.6)+SQR(x[3]-0.7));
+}
+
+int main(void)
+{
+	int i,nfunc,j,ndim=NP;
+	float *x,*y,**p;
+
+	x=vector(1,NP);
+	y=vector(1,MP);
+	p=matrix(1,MP,1,NP);
+	for (i=1;i<=MP;i++) {
+		for (j=1;j<=NP;j++)
+			x[j]=p[i][j]=(i == (j+1) ? 1.0 : 0.0);
+		y[i]=func(x);
+	}
+	amoeba(p,y,ndim,FTOL,func,&nfunc);
+	printf("\nNumber of function evaluations: %3d\n",nfunc);
+	printf("Vertices of final 3-d simplex and\n");
+	printf("function values at the vertices:\n\n");
+	printf("%3s %10s %12s %12s %14s\n\n",
+		"i","x[i]","y[i]","z[i]","function");
+	for (i=1;i<=MP;i++) {
+		printf("%3d ",i);
+		for (j=1;j<=NP;j++) printf("%12.6f ",p[i][j]);
+		printf("%12.6f\n",y[i]);
+	}
+	printf("\nTrue minimum is at (0.5,0.6,0.7)\n");
+	free_matrix(p,1,MP,1,NP);
+	free_vector(y,1,MP);
+	free_vector(x,1,NP);
+	return 0;
+}
+#undef NRANSI