add numerical recipes library

lib/nr/ansi/examples/xqromo.c

@@ -0,0 +1,62 @@
+
+/* Driver for routine qromo */
+
+#include <stdio.h>
+#include <math.h>
+#define NRANSI
+#include "nr.h"
+
+#define X1 0.0
+#define X2 1.5707963
+#define X3 3.1415926
+#define AINF 1.0E20
+#define PI 3.1415926
+
+static float funcl(float x)
+{
+	return (float) (sqrt(x)/sin(x));
+}
+
+static float funcu(float x)
+{
+	return (float) (sqrt(PI-x)/sin(x));
+}
+
+static float fncinf(float x)
+{
+
+	return (float) (sin(x)/(x*x));
+}
+
+static float fncend(float x)
+{
+	return (float) (exp(-x)/sqrt(x));
+}
+
+int main(void)
+{
+	float res1,res2,result;
+
+	printf("\nImproper integrals:\n\n");
+	result=qromo(funcl,X1,X2,midsql);
+	printf("Function: sqrt(x)/sin(x)       Interval: (0,pi/2)\n");
+	printf("Using: MIDSQL                  Result: %8.4f\n\n",result);
+	result=qromo(funcu,X2,X3,midsqu);
+	printf("Function: sqrt(pi-x)/sin(x)    Interval: (pi/2,pi)\n");
+	printf("Using: MIDSQU                  Result: %8.4f\n\n",result);
+	result=qromo(fncinf,X2,AINF,midinf);
+	printf("Function: sin(x)/x**2          Interval: (pi/2,infty)\n");
+	printf("Using: MIDINF                  Result: %8.4f\n\n",result);
+	result=qromo(fncinf,-AINF,-X2,midinf);
+	printf("Function: sin(x)/x**2          Interval: (-infty,-pi/2)\n");
+	printf("Using: MIDINF                  Result: %8.4f\n\n",result);
+	res1=qromo(fncend,X1,X2,midsql);
+	res2=qromo(fncend,X2,AINF,midinf);
+	printf("Function: exp(-x)/sqrt(x)      Interval: (0.0,infty)\n");
+	printf("Using: MIDSQL,MIDINF           Result: %8.4f\n\n",res1+res2);
+	res2=qromo(fncend,X2,AINF,midexp);
+	printf("Function: exp(-x)/sqrt(x)      Interval: (0.0,infty)\n");
+	printf("Using: MIDSQL,MIDEXP           Result: %8.4f\n\n",res1+res2);
+	return 0;
+}
+#undef NRANSI