add numerical recipes library

lib/nr/ansi/examples/xconvlv.c

@@ -0,0 +1,54 @@
+
+/* Driver for routine convlv */
+
+#include <stdio.h>
+#define NRANSI
+#include "nr.h"
+#include "nrutil.h"
+
+#define N 16        /* data array size */
+#define M 9         /* response function dimension - must be odd */
+#define N2 (2*N)
+
+int main(void)
+{
+	unsigned long i,j;
+	int isign;
+	float cmp,*data,*respns,*resp,*ans;
+
+	data=vector(1,N);
+	respns=vector(1,N);
+	resp=vector(1,N);
+	ans=vector(1,N2);
+	for (i=1;i<=N;i++)
+		if ((i >= N/2-N/8) && (i <= N/2+N/8))
+			data[i]=1.0;
+		else
+			data[i]=0.0;
+	for (i=1;i<=M;i++) {
+		if ((i > 2) && (i < 7))
+			respns[i]=1.0;
+		else
+			respns[i]=0.0;
+		resp[i]=respns[i];
+	}
+	isign=1;
+	convlv(data,N,resp,M,isign,ans);
+	/* compare with a direct convolution */
+	printf("%3s %14s %13s\n","i","CONVLV","Expected");
+	for (i=1;i<=N;i++) {
+		cmp=0.0;
+		for (j=1;j<=M/2;j++) {
+			cmp += data[((i-j-1+N) % N)+1]*respns[j+1];
+			cmp += data[((i+j-1) % N)+1]*respns[M-j+1];
+		}
+		cmp += data[i]*respns[1];
+		printf("%3ld %15.6f %12.6f\n",i,ans[i],cmp);
+	}
+	free_vector(ans,1,N2);
+	free_vector(resp,1,N);
+	free_vector(respns,1,N);
+	free_vector(data,1,N);
+	return 0;
+}
+#undef NRANSI