add numerical recipes library

lib/nr/ansi/examples/xelle.c

@@ -0,0 +1,43 @@
+
+/* Driver for routine elle */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+#define NRANSI
+#include "nr.h"
+#include "nrutil.h"
+
+#define MAXSTR 80
+
+#define FAC (3.1415926535/180.0)
+
+int main(void)
+{
+	char txt[MAXSTR];
+	int i,nval;
+	float ak,alpha,phi,val;
+	FILE *fp;
+
+	if ((fp = fopen("fncval.dat","r")) == NULL)
+		nrerror("Data file fncval.dat not found\n");
+	fgets(txt,MAXSTR,fp);
+	while (strncmp(txt,"Legendre Elliptic Integral Second Kind",38)) {
+		fgets(txt,MAXSTR,fp);
+		if (feof(fp)) nrerror("Data not found in fncval.dat\n");
+	}
+	fscanf(fp,"%d %*s",&nval);
+	printf("\n%s\n",txt);
+	printf("%5s %10s %11s %22s\n","phi","sin(alpha)","actual","elle(phi,ak)");
+	for (i=1;i<=nval;i++) {
+		fscanf(fp,"%f %f %f",&phi,&alpha,&val);
+		alpha=alpha*FAC;
+		ak=sin(alpha);
+		phi=phi*FAC;
+		printf("%6.2f %6.2f %18.6e %18.6e\n",phi,ak,val,elle(phi,ak));
+	}
+	fclose(fp);
+	return 0;
+}
+#undef NRANSI