add numerical recipes library

lib/nr/ansi/examples/xquad3d.c

@@ -0,0 +1,55 @@
+
+/* Driver for routine quad3d */
+
+#include <stdio.h>
+#include <math.h>
+#define NRANSI
+#include "nr.h"
+
+#define PI 3.1415927
+#define NVAL 10
+
+static float xmax;
+
+float func(float x,float y,float z)
+{
+	return x*x+y*y+z*z;
+}
+
+float z1(float x,float y)
+{
+	return (float) -sqrt(xmax*xmax-x*x-y*y);
+}
+
+float z2(float x,float y)
+{
+	return (float) sqrt(xmax*xmax-x*x-y*y);
+}
+
+float yy1(float x)
+{
+	return (float) -sqrt(xmax*xmax-x*x);
+}
+
+float yy2(float x)
+{
+	return (float) sqrt(xmax*xmax-x*x);
+}
+
+int main(void)
+{
+	int i;
+	float xmin,s;
+
+	printf("Integral of r^2 over a spherical volume\n\n");
+	printf("%13s %10s %11s\n","radius","QUAD3D","Actual");
+	for (i=1;i<=NVAL;i++) {
+		xmax=0.1*i;
+		xmin = -xmax;
+		s=quad3d(func,xmin,xmax);
+		printf("%12.2f %12.6f %11.6f\n",
+			xmax,s,4.0*PI*pow(xmax,5.0)/5.0);
+	}
+	return 0;
+}
+#undef NRANSI