add numerical recipes library

lib/nr/ansi/recipes/polin2.c

@@ -0,0 +1,19 @@
+
+#define NRANSI
+#include "nrutil.h"
+
+void polin2(float x1a[], float x2a[], float **ya, int m, int n, float x1,
+	float x2, float *y, float *dy)
+{
+	void polint(float xa[], float ya[], int n, float x, float *y, float *dy);
+	int j;
+	float *ymtmp;
+
+	ymtmp=vector(1,m);
+	for (j=1;j<=m;j++) {
+		polint(x2a,ya[j],n,x2,&ymtmp[j],dy);
+	}
+	polint(x1a,ymtmp,m,x1,y,dy);
+	free_vector(ymtmp,1,m);
+}
+#undef NRANSI