add numerical recipes library

lib/nr/cpp/recipes/mprove.cpp

@@ -0,0 +1,18 @@
+#include "nr.h"
+
+void NR::mprove(Mat_I_DP &a, Mat_I_DP &alud, Vec_I_INT &indx, Vec_I_DP &b,
+	Vec_IO_DP &x)
+{
+	int i,j;
+
+	int n=x.size();
+	Vec_DP r(n);
+	for (i=0;i<n;i++) {
+		long double sdp = -b[i];
+		for (j=0;j<n;j++)
+			sdp += (long double) a[i][j]*(long double) x[j];
+		r[i]=sdp;
+	}
+	lubksb(alud,indx,r);
+	for (i=0;i<n;i++) x[i] -= r[i];
+}