1 files changed, 121 insertions, 0 deletions
diff --git a/ffts/Numerical-Recipes-testing/rfftTest.c b/ffts/Numerical-Recipes-testing/rfftTest.c
new file mode 100644
index 0000000..b5e6c92
--- /dev/null
+++ b/ffts/Numerical-Recipes-testing/rfftTest.c
@@ -0,0 +1,121 @@
+/*  A program to test real forward and inverse fast fourier transform routines	*/
+
+#include <NR.H>	/* uses realft from numerical recipes in C to verify riffts */
+			/*change fmin in numerical recipes to fminnr to avoid conflict with fp.h */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <fp.h>
+#include <math.h>
+#include "fftlib.h"
+#include "fftext.h"
+
+#if macintosh
+#include <timer.h>
+#endif
+
+#define NSIZES 	24		/* the number of different fft sizes to test */
+
+#define	BIPRAND(a) (2.0/(RAND_MAX+1.0)*a-1.0)
+
+void main(){
+long 	fftSize[NSIZES] = 	/* size of FFTs, must be powers of 2 */
+		{2,		4, 		8,		16, 		32, 		64, 		128, 	256,
+		512, 	1024, 	2048, 	4096, 	8192, 	16384, 	32768, 	65536,
+		131072, 	262144, 	524288, 	1048576, 	2097152, 	4194304, 	8388608, 	16777216};
+float	*a;
+const long N2 = 2;		/* the number ffts to test at each size */
+long 	isize;
+long 	i1;
+long 	i2;
+long 	TheErr;
+long		N;
+long		M;
+float 	maxerrifft;
+float 	maxerrfft;
+
+unsigned int	randseed = 777;
+int		rannum;
+#if macintosh
+	UnsignedWide 		TheTime1;
+	Microseconds(&TheTime1);
+	randseed = TheTime1.lo;
+#endif
+
+printf(" %6d  Byte Floats \n", sizeof(a[0]));
+printf(" randseed = %10u\n", randseed);
+for (isize = 0; isize < NSIZES; isize++){
+
+	srand(randseed);
+	N = fftSize[isize];
+	printf("rffts size = %8d,  ", N);
+	M = roundtol(LOG2(N));
+
+	TheErr = 0;
+	TheErr = fftInit(M);
+
+	if(!TheErr){
+		a = (float *) malloc(N2*N*sizeof(float) );
+		if (a == 0) TheErr = 2;
+	}
+
+	if(!TheErr){
+
+			/*  set up a simple test case */
+		for (i1=0; i1<N2*N; i1++){
+			rannum = rand();
+			a[i1] = BIPRAND(rannum);
+		}
+
+			/*  first use realft from numerical recipes in C to verify riffts */
+			/*  unfortunately  numerical recipes in C uses backwards time */
+			/*  forward fft, so our answer comes out time reversed */
+		for (i2=0; i2<N2; i2++){
+			realft((a+i2*N)-1, N, 1);
+		}
+		riffts(a, M, N2);
+
+		srand(randseed);
+		for (i2=0; i2<N2; i2++){
+			rannum = rand();
+			maxerrifft = fabs(BIPRAND(rannum)-a[i2*N]);
+			for (i1=1; i1<N; i1++){
+				rannum = rand();
+				maxerrifft = fmax(maxerrifft, fabs(BIPRAND(rannum)-a[i2*N+N-i1]));
+			}
+		}
+
+		printf("maxerrifft = %6.4e,  ", maxerrifft);
+
+			/*  now use iffts to verify ffts */
+		srand(randseed);
+		for (i1=0; i1<N2*N; i1++){
+			rannum = rand();
+			a[i1] = BIPRAND(rannum);
+		}
+
+		riffts(a, M, N2);
+		rffts(a, M, N2);
+
+		maxerrfft = 0;
+		srand(randseed);
+		for (i1=0; i1<N2*N; i1++){
+			rannum = rand();
+			maxerrfft = fmax(maxerrfft, fabs(BIPRAND(rannum)-a[i1]));
+		}
+
+		printf("maxerrfft = %6.4e\n", maxerrfft);
+
+		fftFree();
+		free(a);
+		a = 0;
+	}
+	else{
+		if(TheErr==2)	printf(" out of memory \n");
+		else	printf(" error \n");
+		fftFree();
+	}
+}
+printf(" Done. \n");
+return;
+}