add numerical recipes library

lib/nr/ansi/examples/xgaucof.c

@@ -0,0 +1,44 @@
+
+/* Driver for routine gaucof */
+
+#include <stdio.h>
+#define NRANSI
+#include "nr.h"
+#include "nrutil.h"
+
+#define NP 64
+#define SQRTPI 1.7724539
+
+int main(void)
+{
+	/* Test with Gauss-Hermite */
+	int i,n;
+	float amu0,check,*a,*b,*x,*w;
+
+	a=vector(1,NP);
+	b=vector(1,NP);
+	x=vector(1,NP);
+	w=vector(1,NP);
+	for (;;) {
+		printf("Enter N:\n");
+		if (scanf("%d",&n) == EOF) break;
+		for (i=1;i<n;i++) {
+			a[i]=0.0;
+			b[i+1]=i*0.5;
+		}
+		a[n]=0.0;
+		/* b[1] is arbitrary for call to tqli */
+		amu0=SQRTPI;
+		gaucof(n,a,b,amu0,x,w);
+		printf("%3s %10s %14s\n","#","x(i)","w(i)");
+		for (i=1;i<=n;i++) printf("%3d %14.6e %14.6e\n",i,x[i],w[i]);
+		for (check=0.0,i=1;i<=n;i++) check += w[i];
+		printf("\nCheck value: %15.7e  should be: %15.7e\n",check,SQRTPI);
+	}
+	free_vector(w,1,NP);
+	free_vector(x,1,NP);
+	free_vector(b,1,NP);
+	free_vector(a,1,NP);
+	return 0;
+}
+#undef NRANSI