3.1.3 API Reference

accuracy.c

/*
 * Copyright (c) 2002, 2009 Jens Keiner, Stefan Kunis, Daniel Potts
 *
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by the Free Software
 * Foundation; either version 2 of the License, or (at your option) any later
 * version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 51
 * Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 */

/* $Id: accuracy.c 3198 2009-05-27 14:16:50Z keiner $ */

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

#include "nfft3util.h"
#include "nfft3.h"

void accuracy(int d)
{
  int m,t;
  nnfft_plan my_plan;
  double _Complex *slow;

  int N[d],n[d];
  int M_total,N_total;
  M_total=10000;N_total=1;

  slow=(double _Complex*)nfft_malloc(M_total*sizeof(double _Complex));

  for(t=0; t<d; t++)
    {
      N[t]=(1<<(12/d));
      n[t]=2*N[t];
      N_total*=N[t];
    }

  for(m=0; m<10; m++)
    {
      nnfft_init_guru(&my_plan, d, N_total, M_total, N, n, m,
          PRE_PSI| PRE_PHI_HUT|
          MALLOC_X| MALLOC_V| MALLOC_F_HAT| MALLOC_F);


      nfft_vrand_shifted_unit_double(my_plan.x, d*my_plan.M_total);
      nfft_vrand_shifted_unit_double(my_plan.v, d*my_plan.N_total);

      if(my_plan.nnfft_flags & PRE_PSI)
        nnfft_precompute_psi(&my_plan);

      if(my_plan.nnfft_flags & PRE_LIN_PSI)
        nnfft_precompute_lin_psi(&my_plan);

      if(my_plan.nnfft_flags & PRE_FULL_PSI)
        nnfft_precompute_full_psi(&my_plan);

      if(my_plan.nnfft_flags & PRE_PHI_HUT)
        nnfft_precompute_phi_hut(&my_plan);

      nfft_vrand_unit_complex(my_plan.f_hat, my_plan.N_total);

      nndft_trafo(&my_plan);

      NFFT_SWAP_complex(my_plan.f,slow);

      nnfft_trafo(&my_plan);

      printf("%e, %e\n",
       nfft_error_l_infty_complex(slow, my_plan.f, M_total),
       nfft_error_l_infty_1_complex(slow, my_plan.f, M_total, my_plan.f_hat,
             my_plan.N_total));

      nnfft_finalize(&my_plan);
    }
}

int main(void)
{
  int d;
  for(d=1; d<4; d++)
    accuracy(d);

  return 1;
}

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