add numerical recipes library

lib/nr/k_and_r/recipes/fredex.c

@@ -0,0 +1,31 @@
+
+#include <stdio.h>
+#include <math.h>
+#include "nrutil.h"
+#define PI 3.14159265
+#define N 40
+
+main()  /* Program fredex */
+{
+	void lubksb(),ludcmp(),quadmx();
+	float **a,d,*g,x;
+	int *indx,j;
+
+	indx=ivector(1,N);
+	a=matrix(1,N,1,N);
+	g=vector(1,N);
+	quadmx(a,N);
+	ludcmp(a,N,indx,&d);
+	for (j=1;j<=N;j++) g[j]=sin((j-1)*PI/(N-1));
+	lubksb(a,N,indx,g);
+	for (j=1;j<=N;j++) {
+		x=(j-1)*PI/(N-1);
+		printf("%6.2d %12.6f %12.6f\n",j,x,g[j]);
+	}
+	free_vector(g,1,N);
+	free_matrix(a,1,N,1,N);
+	free_ivector(indx,1,N);
+	return 0;
+}
+#undef N
+#undef PI