add numerical recipes library

lib/nr/ansi/recipes/gaucof.c

@@ -0,0 +1,26 @@
+
+#include <math.h>
+#define NRANSI
+#include "nrutil.h"
+
+void gaucof(int n, float a[], float b[], float amu0, float x[], float w[])
+{
+	void eigsrt(float d[], float **v, int n);
+	void tqli(float d[], float e[], int n, float **z);
+	int i,j;
+	float **z;
+
+	z=matrix(1,n,1,n);
+	for (i=1;i<=n;i++) {
+		if (i != 1) b[i]=sqrt(b[i]);
+		for (j=1;j<=n;j++) z[i][j]=(float)(i == j);
+	}
+	tqli(a,b,n,z);
+	eigsrt(a,z,n);
+	for (i=1;i<=n;i++) {
+		x[i]=a[i];
+		w[i]=amu0*z[1][i]*z[1][i];
+	}
+	free_matrix(z,1,n,1,n);
+}
+#undef NRANSI