add numerical recipes library

lib/nr/ansi/examples/xmedfit.c

@@ -0,0 +1,45 @@
+
+/* Driver for routine medfit */
+
+#include <stdio.h>
+#define NRANSI
+#include "nr.h"
+#include "nrutil.h"
+
+#define NPT 100
+#define SPREAD 0.1
+#define NDATA NPT
+
+int main(void)
+{
+	long idum=(-1984);
+	int i,mwt=1;
+	float a,abdev,b,chi2,q,siga,sigb;
+	float *x,*y,*sig;
+
+	x=vector(1,NDATA);
+	y=vector(1,NDATA);
+	sig=vector(1,NDATA);
+	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;
+	}
+	fit(x,y,NPT,sig,mwt,&a,&b,&siga,&sigb,&chi2,&q);
+	printf("\nAccording to routine FIT the result is:\n");
+	printf("   a =  %8.4f   uncertainty:  %8.4f\n",a,siga);
+	printf("   b =  %8.4f   uncertainty:  %8.4f\n",b,sigb);
+	printf("   chi-squared:  %8.4f  for  %4d  points\n",chi2,NPT);
+	printf("   goodness-of-fit:  %8.4f\n",q);
+	printf("\nAccording to routine MEDFIT the result is:\n");
+	medfit(x,y,NPT,&a,&b,&abdev);
+	printf("   a =  %8.4f\n",a);
+	printf("   b =  %8.4f\n",b);
+	printf("   absolute deviation (per data point): %8.4f\n",abdev);
+	printf("   (note: gaussian SPREAD is %8.4f)\n",SPREAD);
+	free_vector(sig,1,NDATA);
+	free_vector(y,1,NDATA);
+	free_vector(x,1,NDATA);
+	return 0;
+}
+#undef NRANSI