NFFT  3.3.2
construct_data_2d1d.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 "config.h"
00019 
00020 #include <stdlib.h>
00021 #include <math.h>
00022 #ifdef HAVE_COMPLEX_H
00023 #include <complex.h>
00024 #endif
00025 
00026 #include "nfft3.h"
00027 
00037 static void construct(char * file, int N, int M, int Z, fftw_complex *mem)
00038 {
00039   int j,z;                /* some variables */
00040   double tmp;             /* a placeholder */
00041   nfft_plan my_plan;      /* plan for the two dimensional nfft  */
00042   FILE* fp;
00043 
00044   /* initialise my_plan */
00045   nfft_init_2d(&my_plan,N,N,M/Z);
00046 
00047   fp=fopen("knots.dat","r");
00048 
00049   for(j=0;j<my_plan.M_total;j++)
00050   {
00051     fscanf(fp,"%le %le %le",&my_plan.x[2*j+0],&my_plan.x[2*j+1],&tmp);
00052   }
00053   fclose(fp);
00054 
00055   fp=fopen(file,"w");
00056 
00057   for(z=0;z<Z;z++) {
00058     tmp = (double) z;
00059 
00060     for(j=0;j<N*N;j++)
00061       my_plan.f_hat[j] = mem[(z*N*N+N*N*Z/2+j)%(N*N*Z)];
00062 
00063     if(my_plan.flags & PRE_PSI)
00064       nfft_precompute_psi(&my_plan);
00065 
00066     nfft_trafo(&my_plan);
00067 
00068     for(j=0;j<my_plan.M_total;j++)
00069     {
00070       fprintf(fp,"%le %le %le %le %le\n",my_plan.x[2*j+0],my_plan.x[2*j+1],tmp/Z-0.5,
00071               creal(my_plan.f[j]),cimag(my_plan.f[j]));
00072     }
00073   }
00074   fclose(fp);
00075 
00076   nfft_finalize(&my_plan);
00077 }
00078 
00083 static void fft(int N,int M,int Z, fftw_complex *mem)
00084 {
00085   fftw_plan plan;
00086   plan = fftw_plan_many_dft(1, &Z, N*N,
00087                                   mem, NULL,
00088                                   N*N, 1,
00089                                   mem, NULL,
00090                                   N*N,1 ,
00091                                   FFTW_FORWARD, FFTW_ESTIMATE);
00092 
00093   fftw_execute(plan); /* execute the fft */
00094   fftw_destroy_plan(plan);
00095 }
00096 
00101 static void read_data(int N,int M,int Z, fftw_complex *mem)
00102 {
00103   int i,z;
00104   double real;
00105   FILE* fin;
00106   fin=fopen("input_f.dat","r");
00107 
00108   for(z=0;z<Z;z++)
00109   {
00110     for(i=0;i<N*N;i++)
00111     {
00112       fscanf(fin,"%le ",&real );
00113       mem[(z*N*N+N*N*Z/2+i)%(N*N*Z)]=real;
00114     }
00115   }
00116   fclose(fin);
00117 }
00118 
00119 int main(int argc, char **argv)
00120 {
00121   fftw_complex *mem;
00122 
00123   if (argc <= 4) {
00124     printf("usage: ./construct_data FILENAME N M Z\n");
00125     return 1;
00126   }
00127 
00128   mem = (fftw_complex*) nfft_malloc(sizeof(fftw_complex) * atoi(argv[2]) * atoi(argv[2]) * atoi(argv[4]));
00129 
00130   read_data(atoi(argv[2]),atoi(argv[3]),atoi(argv[4]), mem);
00131 
00132   fft(atoi(argv[2]),atoi(argv[3]),atoi(argv[4]), mem);
00133 
00134   construct(argv[1],atoi(argv[2]),atoi(argv[3]),atoi(argv[4]), mem);
00135 
00136   nfft_free(mem);
00137 
00138   return 1;
00139 }
00140 /* \} */