add numerical recipes library

lib/nr/ansi/examples/xavevar.c

@@ -0,0 +1,31 @@
+
+/* Driver for routine avevar */
+
+#include <stdio.h>
+#define NRANSI
+#include "nr.h"
+#include "nrutil.h"
+
+#define NPTS 1000
+#define EPS 0.1
+
+int main(void)
+{
+	int i,j;
+	long idum=(-5);
+	float ave,shift,vrnce,*data;
+
+	data=vector(1,NPTS);
+	/* generate gaussian distributed data */
+	printf("\n%9s %11s %12s\n","shift","average","variance");
+	for (i=1;i<=11;i++) {
+		shift=(i-1)*EPS;
+		for (j=1;j<=NPTS;j++)
+			data[j]=shift+i*gasdev(&idum);
+		avevar(data,NPTS,&ave,&vrnce);
+		printf("%8.2f %11.2f %12.2f\n",shift,ave,vrnce);
+	}
+	free_vector(data,1,NPTS);
+	return 0;
+}
+#undef NRANSI