add numerical recipes library

lib/nr/ansi/recipes/mpinv.c

@@ -0,0 +1,50 @@
+
+#define NRANSI
+#include "nrutil.h"
+#define MF 4
+#define BI (1.0/256)
+
+void mpinv(unsigned char u[], unsigned char v[], int n, int m)
+{
+	void mpmov(unsigned char u[], unsigned char v[], int n);
+	void mpmul(unsigned char w[], unsigned char u[], unsigned char v[], int n,
+		int m);
+	void mpneg(unsigned char u[], int n);
+	unsigned char *rr,*s;
+	int i,j,maxmn,mm;
+	float fu,fv;
+
+	maxmn=IMAX(n,m);
+	rr=cvector(1,1+(maxmn<<1));
+	s=cvector(1,maxmn);
+	mm=IMIN(MF,m);
+	fv=(float) v[mm];
+	for (j=mm-1;j>=1;j--) {
+		fv *= BI;
+		fv += v[j];
+	}
+	fu=1.0/fv;
+	for (j=1;j<=n;j++) {
+		i=(int) fu;
+		u[j]=(unsigned char) i;
+		fu=256.0*(fu-i);
+	}
+	for (;;) {
+		mpmul(rr,u,v,n,m);
+		mpmov(s,&rr[1],n);
+		mpneg(s,n);
+		s[1] -= 254;
+		mpmul(rr,s,u,n,n);
+		mpmov(u,&rr[1],n);
+		for (j=2;j<n;j++)
+			if (s[j]) break;
+		if (j==n) {
+			free_cvector(s,1,maxmn);
+			free_cvector(rr,1,1+(maxmn<<1));
+			return;
+		}
+	}
+}
+#undef MF
+#undef BI
+#undef NRANSI