ffttest.c

/*
Copyright (c) 2004-2011, Max-Planck-Society
All rights reserved.

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    * Redistributions in binary form must reproduce the above copyright
      notice, this list of conditions and the following disclaimer in the
      documentation and/or other materials provided with the distribution.
    * Neither the name of the Max-Planck-Society nor the
      names of its contributors may be used to endorse or promote products
      derived from this software without specific prior written permission.

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WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE MAX-PLANCK-SOCIETY BE LIABLE FOR ANY
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(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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*/

/*
 *  libfftpack is being developed at the Max-Planck-Institut fuer Astrophysik
 *  and financially supported by the Deutsches Zentrum fuer Luft- und Raumfahrt
 *  (DLR).
 */

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

#include "fftpack.h"
#include "ls_fft.h"
#include "bluestein.h"

#define maxlen 4096

static void fill_random (double *data, double *odata, size_t length)
  {
  size_t m;
  for (m=0; m<length; ++m)
    data[m] = odata[m] = rand()/(RAND_MAX+1.0)-0.5;
  }
static void fill_random_c (double *data, double *odata, size_t length)
  {
  size_t m;
  for (m=0; m<length; ++m)
    {
    data[2*m] = odata[2*m] = rand()/(RAND_MAX+1.0)-0.5;
    data[2*m+1] = odata[2*m+1] = 0.;
    }
  }

static void normalize (double *data, size_t length, double norm)
  {
  size_t m;
  for (m=0; m<length; ++m)
    data[m] /= norm;
  }

static double errcalc (double *data, double *odata, size_t length)
  {
  size_t m;
  double sum, errsum;
  sum = errsum = 0;
  for (m=0; m<length; ++m)
    {
    errsum += (data[m]-odata[m])*(data[m]-odata[m]);
    sum += odata[m]*odata[m];
    }
  return sqrt(errsum/sum);
  }

static void test_real(void)
  {
  double data[2*maxlen], odata[2*maxlen];
  int length;
  double err;
  const double epsilon=3e-15;
  real_plan plan;
  for (length=1; length<=maxlen; ++length)
    {
    fill_random_c (data, odata, length);
    plan = make_real_plan (length);
    real_plan_forward_c(plan, data);
    real_plan_backward_c(plan, data);
    normalize (data, 2*length, length);
    kill_real_plan (plan);
    err = errcalc (data, odata, 2*length);
    if (err>epsilon) printf("problem at real length %i: %e\n",length,err);
    }
  for (length=1; length<=maxlen; ++length)
    {
    fill_random (data, odata, length);
    plan = make_real_plan (length);
    real_plan_forward_fftpack (plan, data);
    real_plan_backward_fftpack (plan, data);
    normalize (data, length, length);
    kill_real_plan (plan);
    err = errcalc (data, odata, length);
    if (err>epsilon) printf("problem at real length %i: %e\n",length,err);
    }
  for (length=1; length<=maxlen; ++length)
    {
    fill_random (data, odata, length);
    plan = make_real_plan (length);
    real_plan_forward_fftw (plan, data);
    real_plan_backward_fftw (plan, data);
    normalize (data, length, length);
    kill_real_plan (plan);
    err = errcalc (data, odata, length);
    if (err>epsilon) printf("problem at real length %i: %e\n",length,err);
    }
  for (length=1; length<=maxlen; ++length)
    {
    fill_random (data, odata, length);
    plan = make_real_plan (length);
    real_plan_forward_fftw (plan, data);
    halfcomplex2fftpack (data,plan->length);
    real_plan_backward_fftpack (plan, data);
    normalize (data, length, length);
    kill_real_plan (plan);
    err = errcalc (data, odata, length);
    if (err>epsilon) printf("problem at real length %i: %e\n",length,err);
    }
  for (length=1; length<=maxlen; ++length)
    {
    fill_random (data, odata, length);
    plan = make_real_plan (length);
    real_plan_forward_fftpack (plan, data);
    fftpack2halfcomplex (data,plan->length);
    real_plan_backward_fftw (plan, data);
    normalize (data, length, length);
    kill_real_plan (plan);
    err = errcalc (data, odata, length);
    if (err>epsilon) printf("problem at real length %i: %e\n",length,err);
    }
  }

static void test_complex(void)
  {
  double data[2*maxlen], odata[2*maxlen];
  int length;
  double err;
  const double epsilon=3e-15;
  complex_plan plan;
  for (length=1; length<=maxlen; ++length)
    {
    fill_random (data, odata, 2*length);
    plan = make_complex_plan (length);
    complex_plan_forward(plan, data);
    complex_plan_backward(plan, data);
    normalize (data, 2*length, length);
    kill_complex_plan (plan);
    err = errcalc (data, odata, 2*length);
    if (err>epsilon) printf("problem at complex length %i: %e\n",length,err);
    }
  }

int main(void)
  {
  test_real();
  test_complex();
  return 0;
  }