NFFT  3.3.1
construct_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 
00019 #include "config.h"
00020 
00021 #include <stdlib.h>
00022 #include <math.h>
00023 #ifdef HAVE_COMPLEX_H
00024 #include <complex.h>
00025 #endif
00026 
00027 #include "nfft3.h"
00028 
00038 static void construct(char * file, int N, int M)
00039 {
00040   int j,k;            /* some variables */
00041   double real;
00042   nfft_plan my_plan;  /* plan for the two dimensional nfft  */
00043   FILE* fp;
00044   FILE* fk;
00045   FILE* fi;
00046 
00047   /* initialise my_plan */
00048   nfft_init_2d(&my_plan,N,N,M);
00049 
00050   fp=fopen("knots.dat","r");
00051 
00052   for(j=0;j<my_plan.M_total;j++)
00053   {
00054     fscanf(fp,"%le %le ",&my_plan.x[2*j+0],&my_plan.x[2*j+1]);
00055   }
00056   fclose(fp);
00057 
00058   fi=fopen("input_f.dat","r");
00059   fk=fopen(file,"w");
00060 
00061   for(j=0;j<N;j++)
00062   {
00063     for(k=0;k<N;k++) {
00064       fscanf(fi,"%le ",&real);
00065       my_plan.f_hat[(N*j+k)] = real;
00066     }
00067   }
00068 
00069   if(my_plan.flags & PRE_PSI)
00070     nfft_precompute_psi(&my_plan);
00071 
00072   nfft_trafo(&my_plan);
00073 
00074   for(j=0;j<my_plan.M_total;j++)
00075   {
00076     fprintf(fk,"%le %le %le %le\n",my_plan.x[2*j+0],my_plan.x[2*j+1],creal(my_plan.f[j]),cimag(my_plan.f[j]));
00077   }
00078   fclose(fk);
00079   fclose(fi);
00080 
00081   nfft_finalize(&my_plan);
00082 }
00083 
00084 int main(int argc, char **argv)
00085 {
00086   if (argc <= 3) {
00087     printf("usage: ./construct_data FILENAME N M\n");
00088     return 1;
00089   }
00090 
00091   construct(argv[1],atoi(argv[2]),atoi(argv[3]));
00092 
00093   return 1;
00094 }
00095 /* \} */