add numerical recipes library

lib/nr/ansi/examples/xrlft3.c

@@ -0,0 +1,68 @@
+
+/* Driver for routine rlft3 */
+
+#include <stdio.h>
+#include <math.h>
+#define NRANSI
+#include "nr.h"
+#include "nrutil.h"
+#define IPRNT 20
+
+static unsigned long compare(char *string, float ***arr1, float ***arr2,
+	unsigned long len1, unsigned long len2, unsigned long len3, float eps)
+{
+	unsigned long err=0,i1,i2,i3;
+	float a1,a2;
+
+	printf("%s\n",string);
+	for (i1=1;i1<=len1;i1++)
+		for (i2=1;i2<=len2;i2++)
+			for (i3=1;i3<=len3;i3++) {
+				a1=arr1[i1][i2][i3];
+				a2=arr2[i1][i2][i3];
+				if ((a2 == 0.0 && fabs(a1-a2) > eps) || (fabs((a1-a2)/a2) > eps)) {
+					if (++err <= IPRNT)
+						printf("%d %d %d %12.6f %12.6f\n",
+							i1,i2,i3,a1,a2);
+				}
+			}
+	return err;
+}
+
+#define NX 32
+#define NY 8
+#define NZ 16
+
+#define EPS 0.0008
+
+int main(void)
+{
+	long idum=(-3);
+	unsigned long err,i,j,k,nn1=NX,nn2=NY,nn3=NZ;
+	float fnorm,***data1,***data2,**speq1;
+
+	fnorm=(float)nn1*(float)nn2*(float)nn3/2.0;
+	data1=f3tensor(1,nn1,1,nn2,1,nn3);
+	data2=f3tensor(1,nn1,1,nn2,1,nn3);
+	speq1=matrix(1,nn1,1,nn2<<1);
+	for (i=1;i<=nn1;i++)
+		for (j=1;j<=nn2;j++)
+			for (k=1;k<=nn3;k++)
+				data2[i][j][k]=fnorm*(data1[i][j][k]=2*ran1(&idum)-1);
+	rlft3(data1,speq1,nn1,nn2,nn3,1);
+	/* here would be any processing in Fourier space */
+	rlft3(data1,speq1,nn1,nn2,nn3,-1);
+	err=compare("data",data1,data2,nn1,nn2,nn3,EPS);
+	if (err) {
+		printf("Comparison error at tolerance %12.6f\n",EPS);
+		printf("Total number of errors is %d\n",err);
+	}
+	else {
+		printf("Data compares OK to tolerance %12.6f\n",EPS);
+	}
+	free_matrix(speq1,1,nn1,1,nn2<<1);
+	free_f3tensor(data2,1,nn1,1,nn2,1,nn3);
+	free_f3tensor(data1,1,nn1,1,nn2,1,nn3);
+	return (err > 0);
+}
+#undef NRANSI