add numerical recipes library

lib/nr/ansi/examples/xwtn.c

@@ -0,0 +1,43 @@
+
+/* Driver for routine wtn */
+#include <stdio.h>
+#include <math.h>
+#define NRANSI
+#include "nr.h"
+#include "nrutil.h"
+
+#define EPS 1.0e-06
+#define NX 8
+#define NY 16
+
+int main(void)
+{
+	unsigned long i,j,l,nerror=0,ntot=NX*NY;
+	float *a,*aorg;
+	static unsigned long ndim[]={0,NX,NY};
+
+	aorg=vector(1,ntot);
+	a=vector(1,ntot);
+	pwtset(12);
+	for (i=1;i<=NX;i++)
+		for (j=1;j<=NY;j++) {
+			l=i+(j-1)*NX;
+			aorg[l]=a[l]=(i == j ? -1.0 : 1.0/sqrt(fabs((float)(i-j))));
+		}
+	wtn(a,ndim,2,1,pwt);
+	/* here, one might set the smallest components to zero, encode and transmit
+	the remaining components as a compressed form of the "image" */
+	wtn(a,ndim,2,-1,pwt);
+	for (l=1;l<=ntot;l++) {
+		if (fabs(aorg[l]-a[l]) >= EPS) {
+			printf("Compare Error at element %ld\n",l);
+			nerror++;
+		}
+	}
+	if (nerror) printf("Number of comparision errors: %ld\n",nerror);
+	else printf("transform-inverse transform check OK\n");
+	free_vector(a,1,ntot);
+	free_vector(aorg,1,ntot);
+	return nerror;
+}
+#undef NRANSI