add numerical recipes library

lib/nr/ansi/examples/xselect.c

@@ -0,0 +1,41 @@
+
+/* Driver for routine select */
+
+#include <stdio.h>
+#include <stdlib.h>
+#define NRANSI
+#include "nr.h"
+#include "nrutil.h"
+
+#define MAXSTR 80
+#define NP 100
+
+int main(void)
+{
+	char txt[MAXSTR];
+	unsigned long i,k;
+	float *a,*b,q,s;
+	FILE *fp;
+
+	a=vector(1,NP);
+	b=vector(1,NP);
+	if ((fp = fopen("tarray.dat","r")) == NULL)
+		nrerror("Data file tarray.dat not found\n");
+	fgets(txt,MAXSTR,fp);
+	for (i=1;i<=NP;i++) fscanf(fp,"%f",&a[i]);
+	fclose(fp);
+	for (;;) {
+		printf("Input k\n");
+		if (scanf("%lu",&k) == EOF) break;
+		for (i=1;i<=NP;i++) b[i]=a[i];
+		s=selip(k,NP,a);
+		q=select(k,NP,b);
+		printf("Element in sort position %lu is %6.2f\n",k,q);
+		printf("Cross-check from SELIP routine %6.2f\n",s);
+	}
+	free_vector(b,1,NP);
+	free_vector(a,1,NP);
+	printf("Normal completion\n");
+	return 0;
+}
+#undef NRANSI