add numerical recipes library

lib/nr/cpp/recipes/mpinv.cpp

@@ -0,0 +1,37 @@
+#include "nr.h"
+
+void NR::mpinv(Vec_O_UCHR &u, Vec_I_UCHR &v)
+{
+	const int MF=4;
+	const DP BI=1.0/256.0;
+	int i,j,mm;
+	DP fu,fv;
+
+	int n=u.size();
+	int m=v.size();
+	Vec_UCHR s(n+m),r(2*n+m);
+	mm=MIN(MF,m);
+	fv=DP(v[mm-1]);
+	for (j=mm-2;j>=0;j--) {
+		fv *= BI;
+		fv += v[j];
+	}
+	fu=1.0/fv;
+	for (j=0;j<n;j++) {
+		i=int(fu);
+		u[j]=(unsigned char) i;
+		fu=256.0*(fu-i);
+	}
+	for (;;) {
+		mpmul(s,u,v);
+		mplsh(s);
+		mpneg(s);
+		s[0] += (unsigned char) 2;
+		mpmul(r,s,u);
+		mplsh(r);
+		mpmov(u,r);
+		for (j=1;j<n-1;j++)
+			if (s[j] != 0) break;
+		if (j==n-1) return;
+	}
+}