add numerical recipes library

lib/nr/cpp/recipes/hypdrv.cpp

@@ -0,0 +1,20 @@
+#include <complex>
+#include "nr.h"
+using namespace std;
+
+extern complex<DP> aa,bb,cc,z0,dz;
+
+void NR::hypdrv(const DP s, Vec_I_DP &yy, Vec_O_DP &dyyds)
+{
+	complex<DP> z,y[2],dyds[2];
+
+	y[0]=complex<DP>(yy[0],yy[1]);
+	y[1]=complex<DP>(yy[2],yy[3]);
+	z=z0+s*dz;
+	dyds[0]=y[1]*dz;
+	dyds[1]=(aa*bb*y[0]-(cc-(aa+bb+1.0)*z)*y[1])*dz/(z*(1.0-z));
+	dyyds[0]=real(dyds[0]);
+	dyyds[1]=imag(dyds[0]);
+	dyyds[2]=real(dyds[1]);
+	dyyds[3]=imag(dyds[1]);
+}