add numerical recipes library

lib/nr/cpp/recipes/rebin.cpp

@@ -0,0 +1,19 @@
+#include "nr.h"
+
+void NR::rebin(const DP rc, const int nd, Vec_I_DP &r, Vec_O_DP &xin,
+	Mat_IO_DP &xi, const int j)
+{
+	int i,k=0;
+	DP dr=0.0,xn=0.0,xo=0.0;
+
+	for (i=0;i<nd-1;i++) {
+		while (rc > dr)
+			dr += r[(++k)-1];
+		if (k > 1) xo=xi[j][k-2];
+		xn=xi[j][k-1];
+		dr -= rc;
+		xin[i]=xn-(xn-xo)*dr/r[k-1];
+	}
+	for (i=0;i<nd-1;i++) xi[j][i]=xin[i];
+	xi[j][nd-1]=1.0;
+}