bool Dynamic::get_seed (Point<float>& p, Point<float>& d)
{
uint64_t samples = 0;
std::uniform_int_distribution<size_t> uniform_int (0, fixels.size()-2);
while (1) {
++samples;
const size_t fixel_index = 1 + uniform_int (rng.rng);
const Fixel& fixel = fixels[fixel_index];
if (fixel.get_seed_prob (mu()) > rng()) {
const Point<int>& v (fixel.get_voxel());
const Point<float> vp (v[0]+rng()-0.5, v[1]+rng()-0.5, v[2]+rng()-0.5);
p = transform.voxel2scanner (vp);
bool good_seed = !act;
if (!good_seed) {
if (act->check_seed (p)) {
// Make sure that the seed point has not left the intended voxel
const Point<float> new_v_float (transform.scanner2voxel (p));
const Point<int> new_v (std::round (new_v_float[0]), std::round (new_v_float[1]), std::round (new_v_float[2]));
good_seed = (new_v == v);
}
}
if (good_seed) {
d = fixel.get_dir();
#ifdef DYNAMIC_SEED_DEBUGGING
write_seed (p);
#endif
std::lock_guard<std::mutex> lock (mutex);
total_samples += samples;
++total_seeds;
return true;
}
}
}
return false;
}
// ----- create/delete givens matrix ----- //
givens_sequence_list *generate_givens(){
givens_sequence_list *gsl_r, *gsl_cur;
givens_matrix_list *gml=NULL, *gml_cur;
int *shfl;
alloc_matrix_int(&shfl, MATRIX_SIZE);
for(int i=0; i<MATRIX_SIZE; i++)
shfl[i] = i;
// Fisher-Yates shuffle
for(int i=0; i<MATRIX_SIZE-1; i++){
int k = uniform_int(i,MATRIX_SIZE-1);
int tmp = shfl[k];
shfl[k] = shfl[i];
shfl[i] = tmp;
}
gsl_r = create_givens_sequence_list();
gsl_cur = gsl_r;
const int gm_num = MATRIX_SIZE/GS_NUM;
for(int i=0; i<GS_NUM; i++){
gsl_cur = create_givens_sequence_list();
for(int j=0; j<gm_num/2; j++){
gml_cur = create_givens_matrix_list();
givens_matrix *gm = create_givens_matrix(shfl[gm_num*i + 2*j],shfl[gm_num*i+2*j+1], uniform()*2*MATH_PI);
gml_cur->gm = gm;
if(j == 0){
gsl_cur->gml = gml_cur;
}else{
gml->next = gml_cur;
}
gml = gml_cur;
}
if(i == 0)
gsl_r = gsl_cur;
gsl_cur = gsl_cur->next;
}
free_matrix_int(&shfl);
return gsl_r;
}
