NFFT 3.5.3alpha
accuracy.c
1/*
2 * Copyright (c) 2002, 2017 Jens Keiner, Stefan Kunis, Daniel Potts
3 *
4 * This program is free software; you can redistribute it and/or modify it under
5 * the terms of the GNU General Public License as published by the Free Software
6 * Foundation; either version 2 of the License, or (at your option) any later
7 * version.
8 *
9 * This program is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
11 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
12 * details.
13 *
14 * You should have received a copy of the GNU General Public License along with
15 * this program; if not, write to the Free Software Foundation, Inc., 51
16 * Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
17 */
18
19#include <math.h>
20#include <stdlib.h>
21#include <complex.h>
22
23#include "nfft3.h"
24
26#define CSWAP(x,y) {double _Complex * NFFT_SWAP_temp__; \
27 NFFT_SWAP_temp__=(x); (x)=(y); (y)=NFFT_SWAP_temp__;}
28
29void accuracy(int d)
30{
31 int m,t;
32 nnfft_plan my_plan;
33 double _Complex *slow;
34
35 int N[d],n[d];
36 int M_total,N_total;
37 M_total=10000;N_total=1;
38
39 slow=(double _Complex*)nfft_malloc(M_total*sizeof(double _Complex));
40
41 for(t=0; t<d; t++)
42 {
43 N[t]=(1<<(12/d));
44 n[t]=2*N[t];
45 N_total*=N[t];
46 }
47
49 for(m=0; m<10; m++)
50 {
51 nnfft_init_guru(&my_plan, d, N_total, M_total, N, n, m,
54
55
57 nfft_vrand_shifted_unit_double(my_plan.x, d*my_plan.M_total);
58 nfft_vrand_shifted_unit_double(my_plan.v, d*my_plan.N_total);
59
61 if(my_plan.nnfft_flags & PRE_PSI)
62 nnfft_precompute_psi(&my_plan);
63
64 if(my_plan.nnfft_flags & PRE_LIN_PSI)
66
67 if(my_plan.nnfft_flags & PRE_FULL_PSI)
69
71 if(my_plan.nnfft_flags & PRE_PHI_HUT)
73
75 nfft_vrand_unit_complex(my_plan.f_hat, my_plan.N_total);
76
78 nnfft_trafo_direct(&my_plan);
79
80 CSWAP(my_plan.f,slow);
81
83 nnfft_trafo(&my_plan);
84
85 printf("%e, %e\n",
86 nfft_error_l_infty_complex(slow, my_plan.f, M_total),
87 nfft_error_l_infty_1_complex(slow, my_plan.f, M_total, my_plan.f_hat,
88 my_plan.N_total));
89
91 nnfft_finalize(&my_plan);
92 }
93}
94
95int main(void)
96{
97 int d;
98 for(d=1; d<4; d++)
99 accuracy(d);
100
101 return 1;
102}
#define MALLOC_F_HAT
Definition nfft3.h:194
#define MALLOC_X
Definition nfft3.h:193
#define PRE_FULL_PSI
Definition nfft3.h:192
#define PRE_PSI
Definition nfft3.h:191
#define MALLOC_F
Definition nfft3.h:195
#define PRE_LIN_PSI
Definition nfft3.h:189
#define PRE_PHI_HUT
Definition nfft3.h:187
#define CSWAP(x, y)
Swap two vectors.
Definition infft.h:139
#define MALLOC_V
Definition nfft3.h:429
Header file for the nfft3 library.
void nfft_vrand_unit_complex(fftw_complex *x, const NFFT_INT n)
Inits a vector of random complex numbers in .
void nnfft_precompute_lin_psi(nnfft_plan *ths_plan)
create a lookup table
Definition nnfft.c:367
void nnfft_precompute_full_psi(nnfft_plan *ths_plan)
computes all entries of B explicitly
Definition nnfft.c:424
void nfft_vrand_shifted_unit_double(double *x, const NFFT_INT n)
Inits a vector of random double numbers in .
void nnfft_trafo(nnfft_plan *ths_plan)
user routines
Definition nnfft.c:291
void nnfft_precompute_phi_hut(nnfft_plan *ths_plan)
initialisation of direct transform
Definition nnfft.c:347
void * nfft_malloc(size_t n)
data structure for an NNFFT (nonequispaced in time and frequency fast Fourier transform) plan with do...
Definition nfft3.h:425
double * v
nodes (in fourier domain)
Definition nfft3.h:425
NFFT_INT M_total
Total number of samples.
Definition nfft3.h:425
unsigned nnfft_flags
flags for precomputation, malloc
Definition nfft3.h:425
NFFT_INT N_total
Total number of Fourier coefficients.
Definition nfft3.h:425
fftw_complex * f
Samples.
Definition nfft3.h:425
fftw_complex * f_hat
Fourier coefficients.
Definition nfft3.h:425
double * x
nodes (in time/spatial domain)
Definition nfft3.h:425