add numerical recipes library

lib/nr/k_and_r/recipes/quad3d.c

@@ -0,0 +1,38 @@
+
+static float xsav,ysav;
+static float (*nrfunc)();
+
+float quad3d(func,x1,x2)
+float (*func)(),x1,x2;
+{
+	float f1(),qgaus();
+
+	nrfunc=func;
+	return qgaus(f1,x1,x2);
+}
+
+float f1(x)
+float x;
+{
+	float f2(),qgaus();
+	float yy1(),yy2();
+
+	xsav=x;
+	return qgaus(f2,yy1(x),yy2(x));
+}
+
+float f2(y)
+float y;
+{
+	float f3(),qgaus();
+	float z1(),z2();
+
+	ysav=y;
+	return qgaus(f3,z1(xsav,y),z2(xsav,y));
+}
+
+float f3(z)
+float z;
+{
+	return (*nrfunc)(xsav,ysav,z);
+}