add numerical recipes library

lib/nr/ansi/recipes/chsone.c

@@ -0,0 +1,18 @@
+
+void chsone(float bins[], float ebins[], int nbins, int knstrn, float *df,
+	float *chsq, float *prob)
+{
+	float gammq(float a, float x);
+	void nrerror(char error_text[]);
+	int j;
+	float temp;
+
+	*df=nbins-knstrn;
+	*chsq=0.0;
+	for (j=1;j<=nbins;j++) {
+		if (ebins[j] <= 0.0) nrerror("Bad expected number in chsone");
+		temp=bins[j]-ebins[j];
+		*chsq += temp*temp/ebins[j];
+	}
+	*prob=gammq(0.5*(*df),0.5*(*chsq));
+}