add numerical recipes library

lib/nr/ansi/examples/xfit.c

@@ -0,0 +1,44 @@
+
+/* Driver for routine fit */
+
+#include <stdio.h>
+#define NRANSI
+#include "nr.h"
+#include "nrutil.h"
+
+#define NPT 100
+#define SPREAD 0.5
+
+int main(void)
+{
+	long idum=(-117);
+	int i,mwt;
+	float a,b,chi2,q,siga,sigb,*x,*y,*sig;
+
+	x=vector(1,NPT);
+	y=vector(1,NPT);
+	sig=vector(1,NPT);
+	for (i=1;i<=NPT;i++) {
+		x[i]=0.1*i;
+		y[i] = -2.0*x[i]+1.0+SPREAD*gasdev(&idum);
+		sig[i]=SPREAD;
+	}
+	for (mwt=0;mwt<=1;mwt++) {
+		fit(x,y,NPT,sig,mwt,&a,&b,&siga,&sigb,&chi2,&q);
+		if (mwt == 0)
+			printf("\nIgnoring standard deviations\n");
+		else
+			printf("\nIncluding standard deviations\n");
+		printf("%12s %9.6f %18s %9.6f \n",
+			"a  =  ",a,"uncertainty:",siga);
+		printf("%12s %9.6f %18s %9.6f \n",
+			"b  =  ",b,"uncertainty:",sigb);
+		printf("%19s %14.6f \n","chi-squared: ",chi2);
+		printf("%23s %10.6f \n","goodness-of-fit: ",q);
+	}
+	free_vector(sig,1,NPT);
+	free_vector(y,1,NPT);
+	free_vector(x,1,NPT);
+	return 0;
+}
+#undef NRANSI