perf/ffbench.c - platform/external/valgrind - Git at Google

 // This small program computes a Fast Fourier Transform.  It tests
 // Valgrind's handling of FP operations.  It is representative of all
 // programs that do a lot of FP operations.

 // Licensing: This program is closely based on the one of the same name from
 // http://www.fourmilab.ch/.  The front page of that site says:
 //
 //   "Except for a few clearly-marked exceptions, all the material on this
 //   site is in the public domain and may be used in any manner without
 //   permission, restriction, attribution, or compensation."

 /*

 	Two-dimensional FFT benchmark

 	Designed and implemented by John Walker in April of 1989.

 	This  benchmark executes a specified number of passes (default
 	20) through a loop in which each  iteration  performs  a  fast
 	Fourier transform of a square matrix (default size 256x256) of
 	complex numbers (default precision double),  followed  by  the
 	inverse  transform.   After  all loop iterations are performed
 	the results are checked against known correct values.

 	This benchmark is intended for use on C implementations  which
         define  "int"  as  32 bits or longer and permit allocation and
 	direct addressing of arrays larger than one megabyte.

 	If CAPOUT is defined,  the  result  after  all	iterations  is
 	written  as  a	CA  Lab  pattern  file.   This is intended for
 	debugging in case horribly wrong results  are  obtained  on  a
 	given machine.

 	Archival  timings  are	run  with the definitions below set as
 	follows: Float = double, Asize = 256, Passes = 20, CAPOUT  not
 	defined.

 	Time (seconds)		    System

             2393.93       Sun 3/260, SunOS 3.4, C, "-f68881 -O".
 			  (John Walker).

             1928          Macintosh IIx, MPW C 3.0, "-mc68020
                           -mc68881 -elems881 -m".  (Hugh Hoover).

             1636.1        Sun 4/110, "cc -O3 -lm".  (Michael McClary).
 			  The suspicion is that this is software
 			  floating point.

             1556.7        Macintosh II, A/UX, "cc -O -lm"
 			  (Michael McClary).

 	    1388.8	  Sun 386i/250, SunOS 4.0.1 C
                           "-O /usr/lib/trig.il".  (James Carrington).

 	    1331.93	  Sun 3/60, SunOS 4.0.1, C,
                           "-O4 -f68881 /usr/lib/libm.il"
 			  (Bob Elman).

             1204.0        Apollo Domain DN4000, C, "-cpu 3000 -opt 4".
 			  (Sam Crupi).

 	    1174.66	  Compaq 386/25, SCO Xenix 386 C.
 			  (Peter Shieh).

 	    1068	  Compaq 386/25, SCO Xenix 386,
 			  Metaware High C.  (Robert Wenig).

 	    1064.0	  Sun 3/80, SunOS 4.0.3 Beta C
                           "-O3 -f68881 /usr/lib/libm.il".  (James Carrington).

 	    1061.4	  Compaq 386/25, SCO Xenix, High C 1.4.
 			  (James Carrington).

 	    1059.79	  Compaq 386/25, 387/25, High C 1.4,
 			  DOS|Extender 2.2, 387 inline code
 			  generation.  (Nathan Bender).

 	     777.14	  Compaq 386/25, IIT 3C87-25 (387 Compatible),
 			  High C 1.5, DOS|Extender 2.2, 387 inline
 			  code generation.  (Nathan Bender).

 	     751	  Compaq DeskPro 386/33, High C 1.5 + DOS|Extender,
 			  387 code generation.	(James Carrington).

 	     431.44	  Compaq 386/25, Weitek 3167-25, DOS 3.31,
 			  High C 1.4, DOS|Extender, Weitek code generation.
 			  (Nathan Bender).

 	     344.9	  Compaq 486/25, Metaware High C 1.6, Phar Lap
 			  DOS|Extender, in-line floating point.  (Nathan
 			  Bender).

 	     324.2	  Data General Motorola 88000, 16 Mhz, Gnu C.

              323.1        Sun 4/280, C, "-O4".  (Eric Hill).

 	     254	  Compaq SystemPro 486/33, High C 1.5 + DOS|Extender,
 			  387 code generation.	(James Carrington).

 	     242.8	  Silicon Graphics Personal IRIS, MIPS R2000A,
                           12.5 Mhz, "-O3" (highest level optimisation).
 			  (Mike Zentner).

              233.0        Sun SPARCStation 1, C, "-O4", SunOS 4.0.3.
 			  (Nathan Bender).

 	     187.30	  DEC PMAX 3100, MIPS 2000 chip.
 			  (Robert Wenig).

              120.46       Sun SparcStation 2, C, "-O4", SunOS 4.1.1.
 			  (John Walker).

              120.21       DEC 3MAX, MIPS 3000, "-O4".

 	      98.0	  Intel i860 experimental environment,
 			  OS/2, data caching disabled.	(Kern
 			  Sibbald).

 	      34.9	  Silicon Graphics Indigo², MIPS R4400,
                           175 Mhz, IRIX 5.2, "-O".

 	      32.4	  Pentium 133, Windows NT, Microsoft Visual
 			  C++ 4.0.

 	      17.25	  Silicon Graphics Indigo², MIPS R4400,
                           175 Mhz, IRIX 6.5, "-O3".

 	      14.10	  Dell Dimension XPS R100, Pentium II 400 MHz,
 			  Windows 98, Microsoft Visual C 5.0.

 	      10.7	  Hewlett-Packard Kayak XU 450Mhz Pentium II,
 			  Microsoft Visual C++ 6.0, Windows NT 4.0sp3.	(Nathan Bender).

 	       5.09	  Sun Ultra 2, UltraSPARC V9, 300 MHz, gcc -O3.

 	       0.846	  Dell Inspiron 9100, Pentium 4, 3.4 GHz, gcc -O3.

 */

 #include <stdio.h>
 #include <stdlib.h>
 #include <math.h>
 #include <string.h>

 /*  The  program  may  be  run	with  Float defined as either float or
     double.  With IEEE arithmetic, the same answers are generated  for
     either floating point mode.  */

 #define Float	 double 	   /* Floating point type used in FFT */

 #define Asize	 256		   /* Array edge size */
 #define Passes	 20		   /* Number of FFT/Inverse passes */

 #define max(a,b) ((a)>(b)?(a):(b))
 #define min(a,b) ((a)<=(b)?(a):(b))

 /*

 	Multi-dimensional fast Fourier transform

         Adapted from Press et al., "Numerical Recipes in C".

 */

 #define SWAP(a,b) tempr=(a); (a)=(b); (b)=tempr

 static void fourn(data, nn, ndim, isign)
   Float data[];
   int nn[], ndim, isign;
 {
 	register int i1, i2, i3;
 	int i2rev, i3rev, ip1, ip2, ip3, ifp1, ifp2;
 	int ibit, idim, k1, k2, n, nprev, nrem, ntot;
 	Float tempi, tempr;
 	double theta, wi, wpi, wpr, wr, wtemp;

 	ntot = 1;
 	for (idim = 1; idim <= ndim; idim++)
 	   ntot *= nn[idim];
 	nprev = 1;
 	for (idim = ndim; idim >= 1; idim--) {
 	   n = nn[idim];
 	   nrem = ntot / (n * nprev);
 	   ip1 = nprev << 1;
 	   ip2 = ip1 * n;
 	   ip3 = ip2 * nrem;
 	   i2rev = 1;
 	   for (i2 = 1; i2 <= ip2; i2 += ip1) {
 	      if (i2 < i2rev) {
 		 for (i1 = i2; i1 <= i2 + ip1 - 2; i1 += 2) {
 		    for (i3 = i1; i3 <= ip3; i3 += ip2) {
 		       i3rev = i2rev + i3 - i2;
 		       SWAP(data[i3], data[i3rev]);
 		       SWAP(data[i3 + 1], data[i3rev + 1]);
 		    }
 		 }
 	      }
 	      ibit = ip2 >> 1;
 	      while (ibit >= ip1 && i2rev > ibit) {
 		 i2rev -= ibit;
 		 ibit >>= 1;
 	      }
 	      i2rev += ibit;
 	   }
 	   ifp1 = ip1;
 	   while (ifp1 < ip2) {
 	      ifp2 = ifp1 << 1;
 	      theta = isign * 6.28318530717959 / (ifp2 / ip1);
 	      wtemp = sin(0.5 * theta);
 	      wpr = -2.0 * wtemp * wtemp;
 	      wpi = sin(theta);
 	      wr = 1.0;
 	      wi = 0.0;
 	      for (i3 = 1; i3 <= ifp1; i3 += ip1) {
 		 for (i1 = i3; i1 <= i3 + ip1 - 2; i1 += 2) {
 		    for (i2 = i1; i2 <= ip3; i2 += ifp2) {
 		       k1 = i2;
 		       k2 = k1 + ifp1;
 		       tempr = wr * data[k2] - wi * data[k2 + 1];
 		       tempi = wr * data[k2 + 1] + wi * data[k2];
 		       data[k2] = data[k1] - tempr;
 		       data[k2 + 1] = data[k1 + 1] - tempi;
 		       data[k1] += tempr;
 		       data[k1 + 1] += tempi;
 		    }
 		 }
 		 wr = (wtemp = wr) * wpr - wi * wpi + wr;
 		 wi = wi * wpr + wtemp * wpi + wi;
 	      }
 	      ifp1 = ifp2;
 	   }
 	   nprev *= n;
 	}
 }
 #undef SWAP

 int main()
 {
 	int i, j, k, l, m, npasses = Passes, faedge;
 	Float *fdata /* , *fd */ ;
 	static int nsize[] = {0, 0, 0};
 	long fanum, fasize;
 	double mapbase, mapscale, /* x, */ rmin, rmax, imin, imax;

 	faedge = Asize; 	   /* FFT array edge size */
 	fanum = faedge * faedge;   /* Elements in FFT array */
 	fasize = ((fanum + 1) * 2 * sizeof(Float)); /* FFT array size */
 	nsize[1] = nsize[2] = faedge;

 	fdata = (Float *) malloc(fasize);
 	if (fdata == NULL) {
            fprintf(stdout, "Can't allocate data array.\n");
 	   exit(1);
 	}

 	/*  Generate data array to process.  */

 #define Re(x,y) fdata[1 + (faedge * (x) + (y)) * 2]
 #define Im(x,y) fdata[2 + (faedge * (x) + (y)) * 2]

 	memset(fdata, 0, fasize);
 	for (i = 0; i < faedge; i++) {
 	   for (j = 0; j < faedge; j++) {
 	      if (((i & 15) == 8) || ((j & 15) == 8))
 		 Re(i, j) = 128.0;
 	   }
 	}

 	for (i = 0; i < npasses; i++) {
 /*printf("Pass %d\n", i);*/
 	   /* Transform image to frequency domain. */
 	   fourn(fdata, nsize, 2, 1);

 	   /*  Back-transform to image. */
 	   fourn(fdata, nsize, 2, -1);
 	}

 	{
 	   double r, ij, ar, ai;
 	   rmin = 1e10; rmax = -1e10;
 	   imin = 1e10; imax = -1e10;
 	   ar = 0;
 	   ai = 0;

 	   for (i = 1; i <= fanum; i += 2) {
 	      r = fdata[i];
 	      ij = fdata[i + 1];
 	      ar += r;
 	      ai += ij;
 	      rmin = min(r, rmin);
 	      rmax = max(r, rmax);
 	      imin = min(ij, imin);
 	      imax = max(ij, imax);
 	   }
 #ifdef DEBUG
            printf("Real min %.4g, max %.4g.  Imaginary min %.4g, max %.4g.\n",
 	      rmin, rmax, imin, imax);
            printf("Average real %.4g, imaginary %.4g.\n",
 	      ar / fanum, ai / fanum);
 #endif
 	   mapbase = rmin;
 	   mapscale = 255 / (rmax - rmin);
 	}

 	/* See if we got the right answers. */

 	m = 0;
 	for (i = 0; i < faedge; i++) {
 	   for (j = 0; j < faedge; j++) {
 	      k = (Re(i, j) - mapbase) * mapscale;
 	      l = (((i & 15) == 8) || ((j & 15) == 8)) ? 255 : 0;
 	      if (k != l) {
 		 m++;
 		 fprintf(stdout,
                     "Wrong answer at (%d,%d)!  Expected %d, got %d.\n",
 		    i, j, l, k);
 	      }
 	   }
 	}
 	if (m == 0) {
            fprintf(stdout, "%d passes.  No errors in results.\n", npasses);
 	} else {
            fprintf(stdout, "%d passes.  %d errors in results.\n",
 	      npasses, m);
 	}

 #ifdef CAPOUT

 	/* Output the result of the transform as a CA Lab pattern
 	   file for debugging. */

 	{
 #define SCRX  322
 #define SCRY  200
 #define SCRN  (SCRX * SCRY)
 	   unsigned char patarr[SCRY][SCRX];
 	   FILE *fp;

 /*  Map user external state numbers to internal state index  */

 #define UtoI(x)     (((((x) >> 1) & 0x7F) | ((x) << 7)) & 0xFF)

 	   /* Copy data from FFT buffer to map. */

 	   memset(patarr, 0, sizeof patarr);
 	   l = (SCRX - faedge) / 2;
 	   m = (faedge > SCRY) ? 0 : ((SCRY - faedge) / 2);
 	   for (i = 1; i < faedge; i++) {
 	      for (j = 0; j < min(SCRY, faedge); j++) {
 		 k = (Re(i, j) - mapbase) * mapscale;
 		 patarr[j + m][i + l] = UtoI(k);
 	      }
 	   }

 	   /* Dump pattern map to file. */

            fp = fopen("fft.cap", "w");
 	   if (fp == NULL) {
               fprintf(stdout, "Cannot open output file.\n");
 	      exit(0);
 	   }
            putc(':', fp);
 	   putc(1, fp);
 	   fwrite(patarr, SCRN, 1, fp);
 	   putc(6, fp);
 	   fclose(fp);
 	}
 #endif

 	return 0;
 }
	// This small program computes a Fast Fourier Transform. It tests
	// Valgrind's handling of FP operations. It is representative of all
	// programs that do a lot of FP operations.

	// Licensing: This program is closely based on the one of the same name from
	// http://www.fourmilab.ch/. The front page of that site says:
	//
	// "Except for a few clearly-marked exceptions, all the material on this
	// site is in the public domain and may be used in any manner without
	// permission, restriction, attribution, or compensation."

	/*

	Two-dimensional FFT benchmark

	Designed and implemented by John Walker in April of 1989.

	This benchmark executes a specified number of passes (default
	20) through a loop in which each iteration performs a fast
	Fourier transform of a square matrix (default size 256x256) of
	complex numbers (default precision double), followed by the
	inverse transform. After all loop iterations are performed
	the results are checked against known correct values.

	This benchmark is intended for use on C implementations which
	define "int" as 32 bits or longer and permit allocation and
	direct addressing of arrays larger than one megabyte.

	If CAPOUT is defined, the result after all iterations is
	written as a CA Lab pattern file. This is intended for
	debugging in case horribly wrong results are obtained on a
	given machine.

	Archival timings are run with the definitions below set as
	follows: Float = double, Asize = 256, Passes = 20, CAPOUT not
	defined.

	Time (seconds) System

	2393.93 Sun 3/260, SunOS 3.4, C, "-f68881 -O".
	(John Walker).

	1928 Macintosh IIx, MPW C 3.0, "-mc68020
	-mc68881 -elems881 -m". (Hugh Hoover).

	1636.1 Sun 4/110, "cc -O3 -lm". (Michael McClary).
	The suspicion is that this is software
	floating point.

	1556.7 Macintosh II, A/UX, "cc -O -lm"
	(Michael McClary).

	1388.8 Sun 386i/250, SunOS 4.0.1 C
	"-O /usr/lib/trig.il". (James Carrington).

	1331.93 Sun 3/60, SunOS 4.0.1, C,
	"-O4 -f68881 /usr/lib/libm.il"
	(Bob Elman).

	1204.0 Apollo Domain DN4000, C, "-cpu 3000 -opt 4".
	(Sam Crupi).

	1174.66 Compaq 386/25, SCO Xenix 386 C.
	(Peter Shieh).

	1068 Compaq 386/25, SCO Xenix 386,
	Metaware High C. (Robert Wenig).

	1064.0 Sun 3/80, SunOS 4.0.3 Beta C
	"-O3 -f68881 /usr/lib/libm.il". (James Carrington).

	1061.4 Compaq 386/25, SCO Xenix, High C 1.4.
	(James Carrington).

	1059.79 Compaq 386/25, 387/25, High C 1.4,
	DOS\|Extender 2.2, 387 inline code
	generation. (Nathan Bender).

	777.14 Compaq 386/25, IIT 3C87-25 (387 Compatible),
	High C 1.5, DOS\|Extender 2.2, 387 inline
	code generation. (Nathan Bender).

	751 Compaq DeskPro 386/33, High C 1.5 + DOS\|Extender,
	387 code generation. (James Carrington).

	431.44 Compaq 386/25, Weitek 3167-25, DOS 3.31,
	High C 1.4, DOS\|Extender, Weitek code generation.
	(Nathan Bender).

	344.9 Compaq 486/25, Metaware High C 1.6, Phar Lap
	DOS\|Extender, in-line floating point. (Nathan
	Bender).

	324.2 Data General Motorola 88000, 16 Mhz, Gnu C.

	323.1 Sun 4/280, C, "-O4". (Eric Hill).

	254 Compaq SystemPro 486/33, High C 1.5 + DOS\|Extender,
	387 code generation. (James Carrington).

	242.8 Silicon Graphics Personal IRIS, MIPS R2000A,
	12.5 Mhz, "-O3" (highest level optimisation).
	(Mike Zentner).

	233.0 Sun SPARCStation 1, C, "-O4", SunOS 4.0.3.
	(Nathan Bender).

	187.30 DEC PMAX 3100, MIPS 2000 chip.
	(Robert Wenig).

	120.46 Sun SparcStation 2, C, "-O4", SunOS 4.1.1.
	(John Walker).

	120.21 DEC 3MAX, MIPS 3000, "-O4".

	98.0 Intel i860 experimental environment,
	OS/2, data caching disabled. (Kern
	Sibbald).

	34.9 Silicon Graphics Indigo², MIPS R4400,
	175 Mhz, IRIX 5.2, "-O".

	32.4 Pentium 133, Windows NT, Microsoft Visual
	C++ 4.0.

	17.25 Silicon Graphics Indigo², MIPS R4400,
	175 Mhz, IRIX 6.5, "-O3".

	14.10 Dell Dimension XPS R100, Pentium II 400 MHz,
	Windows 98, Microsoft Visual C 5.0.

	10.7 Hewlett-Packard Kayak XU 450Mhz Pentium II,
	Microsoft Visual C++ 6.0, Windows NT 4.0sp3. (Nathan Bender).

	5.09 Sun Ultra 2, UltraSPARC V9, 300 MHz, gcc -O3.

	0.846 Dell Inspiron 9100, Pentium 4, 3.4 GHz, gcc -O3.

	*/

	#include <stdio.h>
	#include <stdlib.h>
	#include <math.h>
	#include <string.h>

	/* The program may be run with Float defined as either float or
	double. With IEEE arithmetic, the same answers are generated for
	either floating point mode. */

	#define Float double /* Floating point type used in FFT */

	#define Asize 256 /* Array edge size */
	#define Passes 20 /* Number of FFT/Inverse passes */

	#define max(a,b) ((a)>(b)?(a):(b))
	#define min(a,b) ((a)<=(b)?(a):(b))

	/*

	Multi-dimensional fast Fourier transform

	Adapted from Press et al., "Numerical Recipes in C".

	*/

	#define SWAP(a,b) tempr=(a); (a)=(b); (b)=tempr

	static void fourn(data, nn, ndim, isign)
	Float data[];
	int nn[], ndim, isign;
	{
	register int i1, i2, i3;
	int i2rev, i3rev, ip1, ip2, ip3, ifp1, ifp2;
	int ibit, idim, k1, k2, n, nprev, nrem, ntot;
	Float tempi, tempr;
	double theta, wi, wpi, wpr, wr, wtemp;

	ntot = 1;
	for (idim = 1; idim <= ndim; idim++)
	ntot *= nn[idim];
	nprev = 1;
	for (idim = ndim; idim >= 1; idim--) {
	n = nn[idim];
	nrem = ntot / (n * nprev);
	ip1 = nprev << 1;
	ip2 = ip1 * n;
	ip3 = ip2 * nrem;
	i2rev = 1;
	for (i2 = 1; i2 <= ip2; i2 += ip1) {
	if (i2 < i2rev) {
	for (i1 = i2; i1 <= i2 + ip1 - 2; i1 += 2) {
	for (i3 = i1; i3 <= ip3; i3 += ip2) {
	i3rev = i2rev + i3 - i2;
	SWAP(data[i3], data[i3rev]);
	SWAP(data[i3 + 1], data[i3rev + 1]);
	}
	}
	}
	ibit = ip2 >> 1;
	while (ibit >= ip1 && i2rev > ibit) {
	i2rev -= ibit;
	ibit >>= 1;
	}
	i2rev += ibit;
	}
	ifp1 = ip1;
	while (ifp1 < ip2) {
	ifp2 = ifp1 << 1;
	theta = isign * 6.28318530717959 / (ifp2 / ip1);
	wtemp = sin(0.5 * theta);
	wpr = -2.0 * wtemp * wtemp;
	wpi = sin(theta);
	wr = 1.0;
	wi = 0.0;
	for (i3 = 1; i3 <= ifp1; i3 += ip1) {
	for (i1 = i3; i1 <= i3 + ip1 - 2; i1 += 2) {
	for (i2 = i1; i2 <= ip3; i2 += ifp2) {
	k1 = i2;
	k2 = k1 + ifp1;
	tempr = wr * data[k2] - wi * data[k2 + 1];
	tempi = wr * data[k2 + 1] + wi * data[k2];
	data[k2] = data[k1] - tempr;
	data[k2 + 1] = data[k1 + 1] - tempi;
	data[k1] += tempr;
	data[k1 + 1] += tempi;
	}
	}
	wr = (wtemp = wr) * wpr - wi * wpi + wr;
	wi = wi * wpr + wtemp * wpi + wi;
	}
	ifp1 = ifp2;
	}
	nprev *= n;
	}
	}
	#undef SWAP

	int main()
	{
	int i, j, k, l, m, npasses = Passes, faedge;
	Float fdata / , fd / ;
	static int nsize[] = {0, 0, 0};
	long fanum, fasize;
	double mapbase, mapscale, /* x, */ rmin, rmax, imin, imax;

	faedge = Asize; /* FFT array edge size */
	fanum = faedge * faedge; /* Elements in FFT array */
	fasize = ((fanum + 1) * 2 * sizeof(Float)); /* FFT array size */
	nsize[1] = nsize[2] = faedge;

	fdata = (Float *) malloc(fasize);
	if (fdata == NULL) {
	fprintf(stdout, "Can't allocate data array.\n");
	exit(1);
	}

	/* Generate data array to process. */

	#define Re(x,y) fdata[1 + (faedge * (x) + (y)) * 2]
	#define Im(x,y) fdata[2 + (faedge * (x) + (y)) * 2]

	memset(fdata, 0, fasize);
	for (i = 0; i < faedge; i++) {
	for (j = 0; j < faedge; j++) {
	if (((i & 15) == 8) \|\| ((j & 15) == 8))
	Re(i, j) = 128.0;
	}
	}

	for (i = 0; i < npasses; i++) {
	/printf("Pass %d\n", i);/
	/* Transform image to frequency domain. */
	fourn(fdata, nsize, 2, 1);

	/* Back-transform to image. */
	fourn(fdata, nsize, 2, -1);
	}

	{
	double r, ij, ar, ai;
	rmin = 1e10; rmax = -1e10;
	imin = 1e10; imax = -1e10;
	ar = 0;
	ai = 0;

	for (i = 1; i <= fanum; i += 2) {
	r = fdata[i];
	ij = fdata[i + 1];
	ar += r;
	ai += ij;
	rmin = min(r, rmin);
	rmax = max(r, rmax);
	imin = min(ij, imin);
	imax = max(ij, imax);
	}
	#ifdef DEBUG
	printf("Real min %.4g, max %.4g. Imaginary min %.4g, max %.4g.\n",
	rmin, rmax, imin, imax);
	printf("Average real %.4g, imaginary %.4g.\n",
	ar / fanum, ai / fanum);
	#endif
	mapbase = rmin;
	mapscale = 255 / (rmax - rmin);
	}

	/* See if we got the right answers. */

	m = 0;
	for (i = 0; i < faedge; i++) {
	for (j = 0; j < faedge; j++) {
	k = (Re(i, j) - mapbase) * mapscale;
	l = (((i & 15) == 8) \|\| ((j & 15) == 8)) ? 255 : 0;
	if (k != l) {
	m++;
	fprintf(stdout,
	"Wrong answer at (%d,%d)! Expected %d, got %d.\n",
	i, j, l, k);
	}
	}
	}
	if (m == 0) {
	fprintf(stdout, "%d passes. No errors in results.\n", npasses);
	} else {
	fprintf(stdout, "%d passes. %d errors in results.\n",
	npasses, m);
	}

	#ifdef CAPOUT

	/* Output the result of the transform as a CA Lab pattern
	file for debugging. */

	{
	#define SCRX 322
	#define SCRY 200
	#define SCRN (SCRX * SCRY)
	unsigned char patarr[SCRY][SCRX];
	FILE *fp;

	/* Map user external state numbers to internal state index */

	#define UtoI(x) (((((x) >> 1) & 0x7F) \| ((x) << 7)) & 0xFF)

	/* Copy data from FFT buffer to map. */

	memset(patarr, 0, sizeof patarr);
	l = (SCRX - faedge) / 2;
	m = (faedge > SCRY) ? 0 : ((SCRY - faedge) / 2);
	for (i = 1; i < faedge; i++) {
	for (j = 0; j < min(SCRY, faedge); j++) {
	k = (Re(i, j) - mapbase) * mapscale;
	patarr[j + m][i + l] = UtoI(k);
	}
	}

	/* Dump pattern map to file. */

	fp = fopen("fft.cap", "w");
	if (fp == NULL) {
	fprintf(stdout, "Cannot open output file.\n");
	exit(0);
	}
	putc(':', fp);
	putc(1, fp);
	fwrite(patarr, SCRN, 1, fp);
	putc(6, fp);
	fclose(fp);
	}
	#endif

	return 0;
	}