/**
* reconstruct makes a 2d-adjoint-nfft
*/
static void reconstruct(char* filename, int N, int M, int weight)
{
int j; /* some variables */
double weights; /* store one weight temporary */
double real,imag; /* to read the real and imag part of a complex number */
nfft_plan my_plan; /* plan for the two dimensional nfft */
FILE* fin; /* input file */
FILE* fweight; /* input file for the weights */
FILE *fout_real; /* output file */
FILE *fout_imag; /* output file */
int my_N[2],my_n[2];
int flags = PRE_PHI_HUT| PRE_PSI |MALLOC_X| MALLOC_F_HAT|
MALLOC_F| FFTW_INIT| FFT_OUT_OF_PLACE|
FFTW_MEASURE| FFTW_DESTROY_INPUT;
/* initialise nfft */
my_N[0]=N; my_n[0]=ceil(N*1.2);
my_N[1]=N; my_n[1]=ceil(N*1.2);
nfft_init_guru(&my_plan, 2, my_N, M, my_n, 6,flags,
FFTW_MEASURE| FFTW_DESTROY_INPUT);
fin=fopen(filename,"r");
fweight=fopen("weights.dat","r");
for(j=0;j<my_plan.M_total;j++)
{
fscanf(fweight,"%le ",&weights);
fscanf(fin,"%le %le %le %le",&my_plan.x[2*j+0],&my_plan.x[2*j+1],&real,&imag);
my_plan.f[j] = real + _Complex_I*imag;
if (weight)
my_plan.f[j] = my_plan.f[j] * weights;
}
fclose(fweight);
/* precompute psi */
if(my_plan.nfft_flags & PRE_PSI)
nfft_precompute_psi(&my_plan);
/* precompute full psi */
if(my_plan.nfft_flags & PRE_FULL_PSI)
nfft_precompute_full_psi(&my_plan);
/* compute the adjoint nfft */
nfft_adjoint(&my_plan);
fout_real=fopen("output_real.dat","w");
fout_imag=fopen("output_imag.dat","w");
for (j=0;j<N*N;j++) {
fprintf(fout_real,"%le ",creal(my_plan.f_hat[j]));
fprintf(fout_imag,"%le ",cimag(my_plan.f_hat[j]));
}
fclose(fin);
fclose(fout_real);
fclose(fout_imag);
nfft_finalize(&my_plan);
}
/**
* reconstruct makes an 2d-adjoint-nfft for every slice
*/
static void reconstruct(char* filename,int N,int M,int Z, int weight ,fftw_complex *mem)
{
int j,k,z; /* some variables */
double weights; /* store one weight temporary */
double tmp; /* tmp to read the obsolent z from the input file */
double real,imag; /* to read the real and imag part of a complex number */
nfft_plan my_plan; /* plan for the two dimensional nfft */
int my_N[2],my_n[2]; /* to init the nfft */
FILE* fin; /* input file */
FILE* fweight; /* input file for the weights */
/* initialise my_plan */
my_N[0]=N; my_n[0]=ceil(N*1.2);
my_N[1]=N; my_n[1]=ceil(N*1.2);
nfft_init_guru(&my_plan, 2, my_N, M/Z, my_n, 6, PRE_PHI_HUT| PRE_PSI|
MALLOC_X| MALLOC_F_HAT| MALLOC_F|
FFTW_INIT| FFT_OUT_OF_PLACE,
FFTW_MEASURE| FFTW_DESTROY_INPUT);
/* precompute lin psi if set */
if(my_plan.nfft_flags & PRE_LIN_PSI)
nfft_precompute_lin_psi(&my_plan);
fin=fopen(filename,"r");
for(z=0;z<Z;z++) {
fweight=fopen("weights.dat","r");
for(j=0;j<my_plan.M_total;j++)
{
fscanf(fweight,"%le ",&weights);
fscanf(fin,"%le %le %le %le %le",
&my_plan.x[2*j+0],&my_plan.x[2*j+1],&tmp,&real,&imag);
my_plan.f[j] = real + _Complex_I*imag;
if(weight)
my_plan.f[j] = my_plan.f[j] * weights;
}
fclose(fweight);
/* precompute psi if set just one time because the knots equal each slice */
if(z==0 && my_plan.nfft_flags & PRE_PSI)
nfft_precompute_psi(&my_plan);
/* precompute full psi if set just one time because the knots equal each slice */
if(z==0 && my_plan.nfft_flags & PRE_FULL_PSI)
nfft_precompute_full_psi(&my_plan);
/* compute the adjoint nfft */
nfft_adjoint(&my_plan);
for(k=0;k<my_plan.N_total;k++) {
/* write every slice in the memory.
here we make an fftshift direct */
mem[(Z*N*N/2+z*N*N+ k)%(Z*N*N)] = my_plan.f_hat[k];
}
}
fclose(fin);
nfft_finalize(&my_plan);
}
static void reconstruct(char* filename,int N,int M,int iteration , int weight)
{
int j,k,l;
double t0, t1;
double time,min_time,max_time,min_inh,max_inh;
double t,real,imag;
double w,epsilon=0.0000003; /* epsilon is a the break criterium for
the iteration */;
mri_inh_3d_plan my_plan;
solver_plan_complex my_iplan;
FILE* fp,*fw,*fout_real,*fout_imag,*finh,*ftime;
int my_N[3],my_n[3];
int flags = PRE_PHI_HUT| PRE_PSI |MALLOC_X| MALLOC_F_HAT|
MALLOC_F| FFTW_INIT| FFT_OUT_OF_PLACE;
unsigned infft_flags = CGNR | PRECOMPUTE_DAMP;
double Ts;
double W;
int N3;
int m=2;
double sigma = 1.25;
ftime=fopen("readout_time.dat","r");
finh=fopen("inh.dat","r");
min_time=INT_MAX; max_time=INT_MIN;
for(j=0;j<M;j++)
{
fscanf(ftime,"%le ",&time);
if(time<min_time)
min_time = time;
if(time>max_time)
max_time = time;
}
fclose(ftime);
Ts=(min_time+max_time)/2.0;
min_inh=INT_MAX; max_inh=INT_MIN;
for(j=0;j<N*N;j++)
{
fscanf(finh,"%le ",&w);
if(w<min_inh)
min_inh = w;
if(w>max_inh)
max_inh = w;
}
fclose(finh);
N3=ceil((MAX(fabs(min_inh),fabs(max_inh))*(max_time-min_time)/2.0+m/(2*sigma))*4*sigma);
/* N3 has to be even */
if(N3%2!=0)
N3++;
W= MAX(fabs(min_inh),fabs(max_inh))/(0.5-((double) m)/N3);
my_N[0]=N;my_n[0]=ceil(N*sigma);
my_N[1]=N; my_n[1]=ceil(N*sigma);
my_N[2]=N3; my_n[2]=ceil(N3*sigma);
/* initialise nfft */
mri_inh_3d_init_guru(&my_plan, my_N, M, my_n, m, sigma, flags,
FFTW_MEASURE| FFTW_DESTROY_INPUT);
if (weight)
infft_flags = infft_flags | PRECOMPUTE_WEIGHT;
/* initialise my_iplan, advanced */
solver_init_advanced_complex(&my_iplan,(nfft_mv_plan_complex*)(&my_plan), infft_flags );
/* get the weights */
if(my_iplan.flags & PRECOMPUTE_WEIGHT)
{
fw=fopen("weights.dat","r");
for(j=0;j<my_plan.M_total;j++)
{
fscanf(fw,"%le ",&my_iplan.w[j]);
}
fclose(fw);
}
/* get the damping factors */
if(my_iplan.flags & PRECOMPUTE_DAMP)
{
for(j=0;j<N;j++){
for(k=0;k<N;k++) {
int j2= j-N/2;
int k2= k-N/2;
double r=sqrt(j2*j2+k2*k2);
if(r>(double) N/2)
my_iplan.w_hat[j*N+k]=0.0;
else
my_iplan.w_hat[j*N+k]=1.0;
}
}
}
fp=fopen(filename,"r");
ftime=fopen("readout_time.dat","r");
for(j=0;j<my_plan.M_total;j++)
{
fscanf(fp,"%le %le %le %le",&my_plan.plan.x[3*j+0],&my_plan.plan.x[3*j+1],&real,&imag);
my_iplan.y[j]=real+ _Complex_I*imag;
fscanf(ftime,"%le ",&my_plan.plan.x[3*j+2]);
my_plan.plan.x[3*j+2] = (my_plan.plan.x[3*j+2]-Ts)*W/N3;
}
fclose(fp);
fclose(ftime);
finh=fopen("inh.dat","r");
for(j=0;j<N*N;j++)
{
fscanf(finh,"%le ",&my_plan.w[j]);
my_plan.w[j]/=W;
}
fclose(finh);
if(my_plan.plan.flags & PRE_PSI) {
nfft_precompute_psi(&my_plan.plan);
}
if(my_plan.plan.flags & PRE_FULL_PSI) {
nfft_precompute_full_psi(&my_plan.plan);
}
/* init some guess */
for(j=0;j<my_plan.N_total;j++)
{
my_iplan.f_hat_iter[j]=0.0;
}
t0 = nfft_clock_gettime_seconds();
/* inverse trafo */
solver_before_loop_complex(&my_iplan);
for(l=0;l<iteration;l++)
{
/* break if dot_r_iter is smaller than epsilon*/
if(my_iplan.dot_r_iter<epsilon)
break;
fprintf(stderr,"%e, %i of %i\n",sqrt(my_iplan.dot_r_iter),
l+1,iteration);
solver_loop_one_step_complex(&my_iplan);
}
t1 = nfft_clock_gettime_seconds();
t = t1-t0;
fout_real=fopen("output_real.dat","w");
fout_imag=fopen("output_imag.dat","w");
for (j=0;j<N*N;j++) {
/* Verschiebung wieder herausrechnen */
my_iplan.f_hat_iter[j]*=cexp(-2.0*_Complex_I*M_PI*Ts*my_plan.w[j]*W);
fprintf(fout_real,"%le ",creal(my_iplan.f_hat_iter[j]));
fprintf(fout_imag,"%le ",cimag(my_iplan.f_hat_iter[j]));
}
fclose(fout_real);
fclose(fout_imag);
solver_finalize_complex(&my_iplan);
mri_inh_3d_finalize(&my_plan);
}
/** precomputation for fastsum */
void fastsum_precompute(fastsum_plan *ths)
{
int j,k,t;
int n_total;
ticks t0, t1;
ths->MEASURE_TIME_t[0] = 0.0;
ths->MEASURE_TIME_t[1] = 0.0;
ths->MEASURE_TIME_t[2] = 0.0;
ths->MEASURE_TIME_t[3] = 0.0;
#ifdef MEASURE_TIME
t0 = getticks();
#endif
if (ths->flags & NEARFIELD_BOXES)
{
BuildBox(ths);
}
else
{
/** sort source knots */
BuildTree(ths->d,0,ths->x,ths->alpha,ths->N_total);
}
#ifdef MEASURE_TIME
t1 = getticks();
ths->MEASURE_TIME_t[3] += nfft_elapsed_seconds(t1,t0);
#endif
#ifdef MEASURE_TIME
t0 = getticks();
#endif
/** precompute spline values for near field*/
if (!(ths->flags & EXACT_NEARFIELD))
{
if (ths->d==1)
#pragma omp parallel for default(shared) private(k)
for (k=-ths->Ad/2-2; k <= ths->Ad/2+2; k++)
ths->Add[k+ths->Ad/2+2] = regkern1(ths->k, ths->eps_I*(double)k/ths->Ad*2, ths->p, ths->kernel_param, ths->eps_I, ths->eps_B);
else
#pragma omp parallel for default(shared) private(k)
for (k=0; k <= ths->Ad+2; k++)
ths->Add[k] = regkern3(ths->k, ths->eps_I*(double)k/ths->Ad, ths->p, ths->kernel_param, ths->eps_I, ths->eps_B);
}
#ifdef MEASURE_TIME
t1 = getticks();
ths->MEASURE_TIME_t[0] += nfft_elapsed_seconds(t1,t0);
#endif
#ifdef MEASURE_TIME
t0 = getticks();
#endif
/** init NFFT plan for transposed transform in first step*/
for (k=0; k<ths->mv1.M_total; k++)
for (t=0; t<ths->mv1.d; t++)
ths->mv1.x[ths->mv1.d*k+t] = - ths->x[ths->mv1.d*k+t]; /* note the factor -1 for transposed transform instead of adjoint*/
/** precompute psi, the entries of the matrix B */
if(ths->mv1.nfft_flags & PRE_LIN_PSI)
nfft_precompute_lin_psi(&(ths->mv1));
if(ths->mv1.nfft_flags & PRE_PSI)
nfft_precompute_psi(&(ths->mv1));
if(ths->mv1.nfft_flags & PRE_FULL_PSI)
nfft_precompute_full_psi(&(ths->mv1));
#ifdef MEASURE_TIME
t1 = getticks();
ths->MEASURE_TIME_t[1] += nfft_elapsed_seconds(t1,t0);
#endif
/** init Fourier coefficients */
for(k=0; k<ths->mv1.M_total;k++)
ths->mv1.f[k] = ths->alpha[k];
#ifdef MEASURE_TIME
t0 = getticks();
#endif
/** init NFFT plan for transform in third step*/
for (j=0; j<ths->mv2.M_total; j++)
for (t=0; t<ths->mv2.d; t++)
ths->mv2.x[ths->mv2.d*j+t] = - ths->y[ths->mv2.d*j+t]; /* note the factor -1 for conjugated transform instead of standard*/
/** precompute psi, the entries of the matrix B */
if(ths->mv2.nfft_flags & PRE_LIN_PSI)
nfft_precompute_lin_psi(&(ths->mv2));
if(ths->mv2.nfft_flags & PRE_PSI)
nfft_precompute_psi(&(ths->mv2));
if(ths->mv2.nfft_flags & PRE_FULL_PSI)
nfft_precompute_full_psi(&(ths->mv2));
#ifdef MEASURE_TIME
t1 = getticks();
ths->MEASURE_TIME_t[2] += nfft_elapsed_seconds(t1,t0);
#endif
#ifdef MEASURE_TIME
t0 = getticks();
#endif
/** precompute Fourier coefficients of regularised kernel*/
n_total = 1;
for (t=0; t<ths->d; t++)
n_total *= ths->n;
#pragma omp parallel for default(shared) private(j,k,t)
for (j=0; j<n_total; j++)
{
if (ths->d==1)
ths->b[j] = regkern1(ths->k, (double)j / (ths->n) - 0.5, ths->p, ths->kernel_param, ths->eps_I, ths->eps_B)/n_total;
else
{
k=j;
ths->b[j]=0.0;
for (t=0; t<ths->d; t++)
{
ths->b[j] += ((double)(k % (ths->n)) / (ths->n) - 0.5) * ((double)(k % (ths->n)) / (ths->n) - 0.5);
k = k / (ths->n);
}
ths->b[j] = regkern3(ths->k, sqrt(ths->b[j]), ths->p, ths->kernel_param, ths->eps_I, ths->eps_B)/n_total;
}
}
nfft_fftshift_complex(ths->b, ths->mv1.d, ths->mv1.N);
fftw_execute(ths->fft_plan);
nfft_fftshift_complex(ths->b, ths->mv1.d, ths->mv1.N);
#ifdef MEASURE_TIME
t1 = getticks();
ths->MEASURE_TIME_t[0] += nfft_elapsed_seconds(t1,t0);
#endif
}
/**
* reconstruct makes an inverse 3d-nfft
*/
static void reconstruct(char* filename,int N,int M,int Z,int iteration, int weight)
{
int j,k,z,l; /* some variables */
double real,imag; /* to read the real and imag part of a complex number */
nfft_plan my_plan; /* plan for the two dimensional nfft */
solver_plan_complex my_iplan; /* plan for the two dimensional infft */
FILE* fin; /* input file */
FILE* fout_real; /* output file (real part) */
FILE* fout_imag; /* output file (imag part) */
int my_N[3],my_n[3]; /* to init the nfft */
double epsilon=0.0000003; /* tmp to read the obsolent z from 700.acs
epsilon is a the break criterion for
the iteration */
unsigned infft_flags = CGNR | PRECOMPUTE_DAMP; /* flags for the infft */
/* initialise my_plan, specific.
we don't precompute psi */
my_N[0]=Z; my_n[0]=ceil(Z*1.2);
my_N[1]=N; my_n[1]=ceil(N*1.2);
my_N[2]=N; my_n[2]=ceil(N*1.2);
nfft_init_guru(&my_plan, 3, my_N, M, my_n, 6,
PRE_PHI_HUT| PRE_PSI |MALLOC_X| MALLOC_F_HAT|
MALLOC_F| FFTW_INIT| FFT_OUT_OF_PLACE,
FFTW_MEASURE| FFTW_DESTROY_INPUT);
/* precompute lin psi */
if(my_plan.nfft_flags & PRE_LIN_PSI)
nfft_precompute_lin_psi(&my_plan);
if (weight)
infft_flags = infft_flags | PRECOMPUTE_WEIGHT;
/* initialise my_iplan, advanced */
solver_init_advanced_complex(&my_iplan,(nfft_mv_plan_complex*)(&my_plan), infft_flags );
/* get the weights */
if(my_iplan.flags & PRECOMPUTE_WEIGHT)
{
fin=fopen("weights.dat","r");
for(j=0;j<M;j++)
{
fscanf(fin,"%le ",&my_iplan.w[j]);
}
fclose(fin);
}
/* get the damping factors */
if(my_iplan.flags & PRECOMPUTE_DAMP)
{
for(j=0;j<N;j++){
for(k=0;k<N;k++) {
for(z=0;z<N;z++) {
int j2= j-N/2;
int k2= k-N/2;
int z2= z-N/2;
double r=sqrt(j2*j2+k2*k2+z2*z2);
if(r>(double) N/2)
my_iplan.w_hat[z*N*N+j*N+k]=0.0;
else
my_iplan.w_hat[z*N*N+j*N+k]=1.0;
}
}
}
}
/* open the input file */
fin=fopen(filename,"r");
/* open the output files */
fout_real=fopen("output_real.dat","w");
fout_imag=fopen("output_imag.dat","w");
/* read x,y,freal and fimag from the knots */
for(j=0;j<M;j++)
{
fscanf(fin,"%le %le %le %le %le ",&my_plan.x[3*j+1],&my_plan.x[3*j+2], &my_plan.x[3*j+0],
&real,&imag);
my_iplan.y[j] = real + _Complex_I*imag;
}
/* precompute psi */
if(my_plan.nfft_flags & PRE_PSI)
nfft_precompute_psi(&my_plan);
/* precompute full psi */
if(my_plan.nfft_flags & PRE_FULL_PSI)
nfft_precompute_full_psi(&my_plan);
/* init some guess */
for(k=0;k<my_plan.N_total;k++)
my_iplan.f_hat_iter[k]=0.0;
/* inverse trafo */
solver_before_loop_complex(&my_iplan);
for(l=0;l<iteration;l++)
{
/* break if dot_r_iter is smaller than epsilon*/
if(my_iplan.dot_r_iter<epsilon)
break;
fprintf(stderr,"%e, %i of %i\n",sqrt(my_iplan.dot_r_iter),
l+1,iteration);
solver_loop_one_step_complex(&my_iplan);
}
for(l=0;l<Z;l++)
{
for(k=0;k<N*N;k++)
{
/* write every Layer in the files */
fprintf(fout_real,"%le ",creal(my_iplan.f_hat_iter[ k+N*N*l ]));
fprintf(fout_imag,"%le ",cimag(my_iplan.f_hat_iter[ k+N*N*l ]));
}
fprintf(fout_real,"\n");
fprintf(fout_imag,"\n");
}
fclose(fout_real);
fclose(fout_imag);
solver_finalize_complex(&my_iplan);
nfft_finalize(&my_plan);
}
/** inverse NFFT-based mpolar FFT */
static int inverse_mpolar_fft(fftw_complex *f, int T, int R, fftw_complex *f_hat, int NN, int max_i, int m)
{
ticks t0, t1;
int j,k; /**< index for nodes and freqencies */
nfft_plan my_nfft_plan; /**< plan for the nfft-2D */
solver_plan_complex my_infft_plan; /**< plan for the inverse nfft */
double *x, *w; /**< knots and associated weights */
int l; /**< index for iterations */
int N[2],n[2];
int M; /**< number of knots */
N[0]=NN; n[0]=2*N[0]; /**< oversampling factor sigma=2 */
N[1]=NN; n[1]=2*N[1]; /**< oversampling factor sigma=2 */
x = (double *)nfft_malloc(5*T*R/2*(sizeof(double)));
if (x==NULL)
return -1;
w = (double *)nfft_malloc(5*T*R/4*(sizeof(double)));
if (w==NULL)
return -1;
/** init two dimensional NFFT plan */
M=mpolar_grid(T,R,x,w);
nfft_init_guru(&my_nfft_plan, 2, N, M, n, m,
PRE_PHI_HUT| PRE_PSI| MALLOC_X | MALLOC_F_HAT| MALLOC_F| FFTW_INIT | FFT_OUT_OF_PLACE,
FFTW_MEASURE| FFTW_DESTROY_INPUT);
/** init two dimensional infft plan */
solver_init_advanced_complex(&my_infft_plan,(nfft_mv_plan_complex*)(&my_nfft_plan), CGNR | PRECOMPUTE_WEIGHT );
/** init nodes, given samples and weights */
for(j=0;j<my_nfft_plan.M_total;j++)
{
my_nfft_plan.x[2*j+0] = x[2*j+0];
my_nfft_plan.x[2*j+1] = x[2*j+1];
my_infft_plan.y[j] = f[j];
my_infft_plan.w[j] = w[j];
}
/** precompute psi, the entries of the matrix B */
if(my_nfft_plan.nfft_flags & PRE_LIN_PSI)
nfft_precompute_lin_psi(&my_nfft_plan);
if(my_nfft_plan.nfft_flags & PRE_PSI)
nfft_precompute_psi(&my_nfft_plan);
if(my_nfft_plan.nfft_flags & PRE_FULL_PSI)
nfft_precompute_full_psi(&my_nfft_plan);
/** initialise damping factors */
if(my_infft_plan.flags & PRECOMPUTE_DAMP)
for(j=0;j<my_nfft_plan.N[0];j++)
for(k=0;k<my_nfft_plan.N[1];k++)
{
my_infft_plan.w_hat[j*my_nfft_plan.N[1]+k]=
(sqrt(pow(j-my_nfft_plan.N[0]/2,2)+pow(k-my_nfft_plan.N[1]/2,2))>(my_nfft_plan.N[0]/2)?0:1);
}
/** initialise some guess f_hat_0 */
for(k=0;k<my_nfft_plan.N_total;k++)
my_infft_plan.f_hat_iter[k] = 0.0 + _Complex_I*0.0;
t0 = getticks();
/** solve the system */
solver_before_loop_complex(&my_infft_plan);
if (max_i<1)
{
l=1;
for(k=0;k<my_nfft_plan.N_total;k++)
my_infft_plan.f_hat_iter[k] = my_infft_plan.p_hat_iter[k];
}
else
{
for(l=1;l<=max_i;l++)
{
solver_loop_one_step_complex(&my_infft_plan);
}
}
t1 = getticks();
GLOBAL_elapsed_time = nfft_elapsed_seconds(t1,t0);
/** copy result */
for(k=0;k<my_nfft_plan.N_total;k++)
f_hat[k] = my_infft_plan.f_hat_iter[k];
/** finalise the plans and free the variables */
solver_finalize_complex(&my_infft_plan);
nfft_finalize(&my_nfft_plan);
nfft_free(x);
nfft_free(w);
return EXIT_SUCCESS;
}
/** NFFT-based mpolar FFT */
static int mpolar_fft(fftw_complex *f_hat, int NN, fftw_complex *f, int T, int R, int m)
{
ticks t0, t1;
int j,k; /**< index for nodes and freqencies */
nfft_plan my_nfft_plan; /**< plan for the nfft-2D */
double *x, *w; /**< knots and associated weights */
int N[2],n[2];
int M; /**< number of knots */
N[0]=NN; n[0]=2*N[0]; /**< oversampling factor sigma=2 */
N[1]=NN; n[1]=2*N[1]; /**< oversampling factor sigma=2 */
x = (double *)nfft_malloc(5*T*R/2*(sizeof(double)));
if (x==NULL)
return -1;
w = (double *)nfft_malloc(5*T*R/4*(sizeof(double)));
if (w==NULL)
return -1;
/** init two dimensional NFFT plan */
M=mpolar_grid(T,R,x,w);
nfft_init_guru(&my_nfft_plan, 2, N, M, n, m,
PRE_PHI_HUT| PRE_PSI| MALLOC_X | MALLOC_F_HAT| MALLOC_F| FFTW_INIT | FFT_OUT_OF_PLACE,
FFTW_MEASURE| FFTW_DESTROY_INPUT);
/** init nodes from mpolar grid*/
for(j=0;j<my_nfft_plan.M_total;j++)
{
my_nfft_plan.x[2*j+0] = x[2*j+0];
my_nfft_plan.x[2*j+1] = x[2*j+1];
}
/** precompute psi, the entries of the matrix B */
if(my_nfft_plan.nfft_flags & PRE_LIN_PSI)
nfft_precompute_lin_psi(&my_nfft_plan);
if(my_nfft_plan.nfft_flags & PRE_PSI)
nfft_precompute_psi(&my_nfft_plan);
if(my_nfft_plan.nfft_flags & PRE_FULL_PSI)
nfft_precompute_full_psi(&my_nfft_plan);
/** init Fourier coefficients from given image */
for(k=0;k<my_nfft_plan.N_total;k++)
my_nfft_plan.f_hat[k] = f_hat[k];
t0 = getticks();
/** NFFT-2D */
nfft_trafo(&my_nfft_plan);
t1 = getticks();
GLOBAL_elapsed_time = nfft_elapsed_seconds(t1,t0);
/** copy result */
for(j=0;j<my_nfft_plan.M_total;j++)
f[j] = my_nfft_plan.f[j];
/** finalise the plans and free the variables */
nfft_finalize(&my_nfft_plan);
nfft_free(x);
nfft_free(w);
return EXIT_SUCCESS;
}
/** computes the inverse discrete Radon transform of Rf
* on the grid given by gridfcn() with T angles and R offsets
* by a NFFT-based CG-type algorithm
*/
int Inverse_Radon_trafo(int (*gridfcn)(), int T, int S, double *Rf, int NN, double *f, int max_i)
{
int j,k; /**< index for nodes and freqencies */
nfft_plan my_nfft_plan; /**< plan for the nfft-2D */
solver_plan_complex my_infft_plan; /**< plan for the inverse nfft */
fftw_complex *fft; /**< variable for the fftw-1Ds */
fftw_plan my_fftw_plan; /**< plan for the fftw-1Ds */
int t,r; /**< index for directions and offsets */
double *x, *w; /**< knots and associated weights */
int l; /**< index for iterations */
int N[2],n[2];
int M=T*S;
N[0]=NN; n[0]=2*N[0];
N[1]=NN; n[1]=2*N[1];
fft = (fftw_complex *)nfft_malloc(S*sizeof(fftw_complex));
my_fftw_plan = fftw_plan_dft_1d(S,fft,fft,FFTW_FORWARD,FFTW_MEASURE);
x = (double *)nfft_malloc(2*T*S*(sizeof(double)));
if (x==NULL)
return -1;
w = (double *)nfft_malloc(T*S*(sizeof(double)));
if (w==NULL)
return -1;
/** init two dimensional NFFT plan */
nfft_init_guru(&my_nfft_plan, 2, N, M, n, 4,
PRE_PHI_HUT| PRE_PSI| MALLOC_X | MALLOC_F_HAT| MALLOC_F| FFTW_INIT | FFT_OUT_OF_PLACE,
FFTW_MEASURE| FFTW_DESTROY_INPUT);
/** init two dimensional infft plan */
solver_init_advanced_complex(&my_infft_plan,(nfft_mv_plan_complex*)(&my_nfft_plan), CGNR | PRECOMPUTE_WEIGHT);
/** init nodes and weights of grid*/
gridfcn(T,S,x,w);
for(j=0;j<my_nfft_plan.M_total;j++)
{
my_nfft_plan.x[2*j+0] = x[2*j+0];
my_nfft_plan.x[2*j+1] = x[2*j+1];
if (j%S)
my_infft_plan.w[j] = w[j];
else
my_infft_plan.w[j] = 0.0;
}
/** precompute psi, the entries of the matrix B */
if(my_nfft_plan.nfft_flags & PRE_LIN_PSI)
nfft_precompute_lin_psi(&my_nfft_plan);
if(my_nfft_plan.nfft_flags & PRE_PSI)
nfft_precompute_psi(&my_nfft_plan);
if(my_nfft_plan.nfft_flags & PRE_FULL_PSI)
nfft_precompute_full_psi(&my_nfft_plan);
/** compute 1D-ffts and init given samples and weights */
for(t=0; t<T; t++)
{
/* for(r=0; r<R/2; r++)
fft[r] = cexp(I*KPI*r)*Rf[t*R+(r+R/2)];
for(r=0; r<R/2; r++)
fft[r+R/2] = cexp(I*KPI*r)*Rf[t*R+r];
*/
for(r=0; r<S; r++)
fft[r] = Rf[t*S+r] + _Complex_I*0.0;
nfft_fftshift_complex(fft, 1, &S);
fftw_execute(my_fftw_plan);
nfft_fftshift_complex(fft, 1, &S);
my_infft_plan.y[t*S] = 0.0;
for(r=-S/2+1; r<S/2; r++)
my_infft_plan.y[t*S+(r+S/2)] = fft[r+S/2]/KERNEL(r);
}
/** initialise some guess f_hat_0 */
for(k=0;k<my_nfft_plan.N_total;k++)
my_infft_plan.f_hat_iter[k] = 0.0 + _Complex_I*0.0;
/** solve the system */
solver_before_loop_complex(&my_infft_plan);
if (max_i<1)
{
l=1;
for(k=0;k<my_nfft_plan.N_total;k++)
my_infft_plan.f_hat_iter[k] = my_infft_plan.p_hat_iter[k];
}
else
{
for(l=1;l<=max_i;l++)
{
solver_loop_one_step_complex(&my_infft_plan);
/*if (sqrt(my_infft_plan.dot_r_iter)<=1e-12) break;*/
}
}
/*printf("after %d iteration(s): weighted 2-norm of original residual vector = %g\n",l-1,sqrt(my_infft_plan.dot_r_iter));*/
/** copy result */
for(k=0;k<my_nfft_plan.N_total;k++)
f[k] = creal(my_infft_plan.f_hat_iter[k]);
/** finalise the plans and free the variables */
fftw_destroy_plan(my_fftw_plan);
nfft_free(fft);
solver_finalize_complex(&my_infft_plan);
nfft_finalize(&my_nfft_plan);
nfft_free(x);
nfft_free(w);
return 0;
}