NFFT  3.3.2
reconstruct_data_2d.c
00001 /*
00002  * Copyright (c) 2002, 2016 Jens Keiner, Stefan Kunis, Daniel Potts
00003  *
00004  * This program is free software; you can redistribute it and/or modify it under
00005  * the terms of the GNU General Public License as published by the Free Software
00006  * Foundation; either version 2 of the License, or (at your option) any later
00007  * version.
00008  *
00009  * This program is distributed in the hope that it will be useful, but WITHOUT
00010  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
00011  * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
00012  * details.
00013  *
00014  * You should have received a copy of the GNU General Public License along with
00015  * this program; if not, write to the Free Software Foundation, Inc., 51
00016  * Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
00017  */
00018 #include <math.h>
00019 #include <stdlib.h>
00020 #include <complex.h>
00021 
00022 #include "nfft3.h"
00023 
00033 static void reconstruct(char* filename,int N,int M,int iteration, int weight)
00034 {
00035   int j,k,l;                    /* some variables  */
00036   double t0, t1;
00037   double real,imag,t;           /* to read the real and imag part of a complex number */
00038   nfft_plan my_plan;            /* plan for the two dimensional nfft  */
00039   solver_plan_complex my_iplan; /* plan for the two dimensional infft */
00040   FILE* fin;                    /* input file                         */
00041   FILE* fout_real;              /* output file                        */
00042   FILE* fout_imag;              /* output file                        */
00043   int my_N[2],my_n[2];          /* to init the nfft */
00044   double epsilon=0.0000003;     /* epsilon is a the break criterium for
00045                                    the iteration */
00046   unsigned infft_flags = CGNR | PRECOMPUTE_DAMP;  /* flags for the infft*/
00047   int m = 6;
00048   double alpha = 2.0;
00049   /* initialise my_plan */
00050   my_N[0]=N; my_n[0]=ceil(N*alpha);
00051   my_N[1]=N; my_n[1]=ceil(N*alpha);
00052   nfft_init_guru(&my_plan, 2, my_N, M, my_n, m, PRE_PHI_HUT| PRE_PSI|
00053                          MALLOC_X| MALLOC_F_HAT| MALLOC_F|
00054                          FFTW_INIT| FFT_OUT_OF_PLACE,
00055                          FFTW_MEASURE| FFTW_DESTROY_INPUT);
00056 
00057   /* precompute lin psi if set */
00058   if(my_plan.flags & PRE_LIN_PSI)
00059     nfft_precompute_lin_psi(&my_plan);
00060 
00061   /* set the flags for the infft*/
00062   if (weight)
00063     infft_flags = infft_flags | PRECOMPUTE_WEIGHT;
00064 
00065   /* initialise my_iplan, advanced */
00066   solver_init_advanced_complex(&my_iplan,(nfft_mv_plan_complex*)&my_plan, infft_flags );
00067 
00068   /* get the weights */
00069   if(my_iplan.flags & PRECOMPUTE_WEIGHT)
00070   {
00071     fin=fopen("weights.dat","r");
00072     for(j=0;j<my_plan.M_total;j++)
00073     {
00074         fscanf(fin,"%le ",&my_iplan.w[j]);
00075     }
00076     fclose(fin);
00077   }
00078 
00079   /* get the damping factors */
00080   if(my_iplan.flags & PRECOMPUTE_DAMP)
00081   {
00082     for(j=0;j<N;j++){
00083       for(k=0;k<N;k++) {
00084         int j2= j-N/2;
00085         int k2= k-N/2;
00086         double r=sqrt(j2*j2+k2*k2);
00087         if(r>(double) N/2)
00088           my_iplan.w_hat[j*N+k]=0.0;
00089         else
00090           my_iplan.w_hat[j*N+k]=1.0;
00091       }
00092     }
00093   }
00094 
00095   /* open the input file */
00096   fin=fopen(filename,"r");
00097 
00098   /* read x,y,freal and fimag from the knots */
00099   for(j=0;j<my_plan.M_total;j++)
00100   {
00101     fscanf(fin,"%le %le %le %le ",&my_plan.x[2*j+0],&my_plan.x[2*j+1],
00102     &real,&imag);
00103     my_iplan.y[j] = real + _Complex_I*imag;
00104   }
00105 
00106   fclose(fin);
00107 
00108   /* precompute psi */
00109   if(my_plan.flags & PRE_PSI)
00110     nfft_precompute_psi(&my_plan);
00111 
00112   /* precompute full psi */
00113   if(my_plan.flags & PRE_FULL_PSI)
00114       nfft_precompute_full_psi(&my_plan);
00115 
00116   /* init some guess */
00117   for(k=0;k<my_plan.N_total;k++)
00118     my_iplan.f_hat_iter[k]=0.0;
00119 
00120   t0 = nfft_clock_gettime_seconds();
00121 
00122   /* inverse trafo */
00123   solver_before_loop_complex(&my_iplan);
00124   for(l=0;l<iteration;l++)
00125   {
00126     /* break if dot_r_iter is smaller than epsilon*/
00127     if(my_iplan.dot_r_iter<epsilon)
00128       break;
00129     fprintf(stderr,"%e,  %i of %i\n",sqrt(my_iplan.dot_r_iter),
00130     l+1,iteration);
00131     solver_loop_one_step_complex(&my_iplan);
00132   }
00133 
00134 
00135   t1 = nfft_clock_gettime_seconds();
00136   t=t1-t0;
00137 
00138   fout_real=fopen("output_real.dat","w");
00139   fout_imag=fopen("output_imag.dat","w");
00140 
00141   for(k=0;k<my_plan.N_total;k++) {
00142     fprintf(fout_real,"%le ", creal(my_iplan.f_hat_iter[k]));
00143     fprintf(fout_imag,"%le ", cimag(my_iplan.f_hat_iter[k]));
00144   }
00145 
00146   fclose(fout_real);
00147   fclose(fout_imag);
00148 
00149   /* finalize the infft */
00150   solver_finalize_complex(&my_iplan);
00151 
00152   /* finalize the nfft */
00153   nfft_finalize(&my_plan);
00154 }
00155 
00156 int main(int argc, char **argv)
00157 {
00158   if (argc <= 5) {
00159     printf("usage: ./reconstruct_data_2d FILENAME N M ITER WEIGHTS\n");
00160     return 1;
00161   }
00162 
00163   reconstruct(argv[1],atoi(argv[2]),atoi(argv[3]),atoi(argv[4]),atoi(argv[5]));
00164 
00165   return 1;
00166 }
00167 /* \} */