add numerical recipes library

lib/nr/k_and_r/recipes/splin2.c

@@ -0,0 +1,20 @@
+
+#include "nrutil.h"
+
+void splin2(x1a,x2a,ya,y2a,m,n,x1,x2,y)
+float **y2a,**ya,*y,x1,x1a[],x2,x2a[];
+int m,n;
+{
+	void spline(),splint();
+	int j;
+	float *ytmp,*yytmp;
+
+	ytmp=vector(1,m);
+	yytmp=vector(1,m);
+	for (j=1;j<=m;j++)
+		splint(x2a,ya[j],y2a[j],n,x2,&yytmp[j]);
+	spline(x1a,yytmp,m,1.0e30,1.0e30,ytmp);
+	splint(x1a,yytmp,ytmp,m,x1,y);
+	free_vector(yytmp,1,m);
+	free_vector(ytmp,1,m);
+}