39 static void construct(
char * file,
int N,
int M,
int Z, fftw_complex *mem)
47 nfft_init_2d(&my_plan,N,N,M/Z);
49 fp=fopen(
"knots.dat",
"r");
53 fscanf(fp,
"%le %le %le",&my_plan.
x[2*j+0],&my_plan.
x[2*j+1],&tmp);
63 my_plan.
f_hat[j] = mem[(z*N*N+N*N*Z/2+j)%(N*N*Z)];
65 if(my_plan.
flags & PRE_PSI)
66 nfft_precompute_psi(&my_plan);
72 fprintf(fp,
"%le %le %le %le %le\n",my_plan.
x[2*j+0],my_plan.
x[2*j+1],tmp/Z-0.5,
73 creal(my_plan.
f[j]),cimag(my_plan.
f[j]));
78 nfft_finalize(&my_plan);
85 static void fft(
int N,
int M,
int Z, fftw_complex *mem)
88 plan = fftw_plan_many_dft(1, &Z, N*N,
93 FFTW_FORWARD, FFTW_ESTIMATE);
96 fftw_destroy_plan(plan);
103 static void read_data(
int N,
int M,
int Z, fftw_complex *mem)
108 fin=fopen(
"input_f.dat",
"r");
114 fscanf(fin,
"%le ",&real );
115 mem[(z*N*N+N*N*Z/2+i)%(N*N*Z)]=real;
121 int main(
int argc,
char **argv)
126 printf(
"usage: ./construct_data FILENAME N M Z\n");
130 mem = (fftw_complex*)
nfft_malloc(
sizeof(fftw_complex) * atoi(argv[2]) * atoi(argv[2]) * atoi(argv[4]));
132 read_data(atoi(argv[2]),atoi(argv[3]),atoi(argv[4]), mem);
134 fft(atoi(argv[2]),atoi(argv[3]),atoi(argv[4]), mem);
136 construct(argv[1],atoi(argv[2]),atoi(argv[3]),atoi(argv[4]), mem);
fftw_complex * f_hat
Fourier coefficients.
static void read_data(int N, int M, int Z, fftw_complex *mem)
read fills the memory with the file input_data_f.dat as the real part of f and with zeros for the ima...
static void fft(int N, int M, int Z, fftw_complex *mem)
fft makes an 1D-ftt for every knot through all layers
data structure for an NFFT (nonequispaced fast Fourier transform) plan with double precision ...
NFFT_INT M_total
Total number of samples.
void * nfft_malloc(size_t n)
double * x
Nodes in time/spatial domain, size is doubles.
unsigned flags
Flags for precomputation, (de)allocation, and FFTW usage, default setting is PRE_PHI_HUT | PRE_PSI | ...
static void construct(char *file, int N, int M, int Z, fftw_complex *mem)
construct makes an 2d-nfft for every slice