add numerical recipes library

lib/nr/ansi/examples/xchsone.c

@@ -0,0 +1,39 @@
+
+/* Driver for routine chsone */
+
+#include <stdio.h>
+#include <math.h>
+#define NRANSI
+#include "nr.h"
+#include "nrutil.h"
+
+#define NBINS 10
+#define NPTS 2000
+
+int main(void)
+{
+	long idum=(-15);
+	int i,ibin,j;
+	float chsq,df,prob,x,*bins,*ebins;
+
+	bins=vector(1,NBINS);
+	ebins=vector(1,NBINS);
+	for (j=1;j<=NBINS;j++) bins[j]=0.0;
+	for (i=1;i<=NPTS;i++) {
+		x=expdev(&idum);
+		ibin=(int) (x*NBINS/3.0)+1;
+		if (ibin <= NBINS) ++bins[ibin];
+	}
+	for (i=1;i<=NBINS;i++)
+		ebins[i]=3.0*NPTS/NBINS*exp(-3.0*(i-0.5)/NBINS);
+	chsone(bins,ebins,NBINS,0,&df,&chsq,&prob);
+	printf("%15s %15s\n","expected","observed");
+	for (i=1;i<=NBINS;i++)
+		printf("%14.2f %15.2f\n",ebins[i],bins[i]);
+	printf("\n%19s %10.4f\n","chi-squared:",chsq);
+	printf("%19s %10.4f\n","probability:",prob);
+	free_vector(ebins,1,NBINS);
+	free_vector(bins,1,NBINS);
+	return 0;
+}
+#undef NRANSI