add numerical recipes library

lib/nr/ansi/recipes/splin2.c

@@ -0,0 +1,22 @@
+
+#define NRANSI
+#include "nrutil.h"
+
+void splin2(float x1a[], float x2a[], float **ya, float **y2a, int m, int n,
+	float x1, float x2, float *y)
+{
+	void spline(float x[], float y[], int n, float yp1, float ypn, float y2[]);
+	void splint(float xa[], float ya[], float y2a[], int n, float x, float *y);
+	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);
+}
+#undef NRANSI