void incomplete_qr(int m, int n, const int *Acolstart, const int *Arowindex, const double *Avalue,
double Qdroptol,
const int *Rcolstart, const int *Rrowindex, double *Rvalue, double *Rdiag)
{
// column storage for intermediate Q
std::vector<StaticSparseVector> Q(n);
// for each column of Q, how many more times it will be used in making R
// (once this gets decremented to zero, we can free the column)
std::vector<int> dependency_count(n,0);
for(int i=0; i<n; ++i){
for(int a=Rcolstart[i]; a<Rcolstart[i+1]; ++a){
int j=Rrowindex[a];
if(j<i) ++dependency_count[j];
}
}
// construct R a column at a time
for(int i=0; i<n; ++i){
DynamicSparseVector q;
copy_column(Acolstart[i], Acolstart[i+1], Arowindex, Avalue, q);
for(int a=Rcolstart[i]; a<Rcolstart[i+1]; ++a){
int j=Rrowindex[a];
if(j<i){
Rvalue[a]=dot_product(Q[j], q);
add_to_vector(-Rvalue[a], Q[j], q);
--dependency_count[j];
if(dependency_count[j]==0) Q[j].clear();
}else // j>i
Rvalue[a]=0; // ideally structure of R is upper triangular, so this waste of space won't happen
}
Rdiag[i]=vector_norm(q);
copy_large_entries(q, Qdroptol*Rdiag[i], Q[i]);
normalize(Q[i]);
}
}
void add_point(face_t *self, const char *point_string) {
string_iterator_t *it;
int *v;
int *vt;
int *vn;
switch(nb_delimiters(point_string, SUB_DELIMITER)) {
// f v1 v2 v3 [v*]*
case 0:
v = malloc(sizeof(int));
*v = atoi(point_string);
add_to_vector(self->vertexes, v);
break;
// f v1/vt1 v2/vt2 v3/vt3 [v*/vt*]*
case 1:
it = new_string_iterator(point_string, SUB_DELIMITER);
v = malloc(sizeof(int));
vt = malloc(sizeof(int));
if(self->textures == NULL) {
self->textures = new_vector(MINIMAL_POINTS);
}
*v = atoi(it->current_string);
add_to_vector(self->vertexes, v);
next_string_iterator(it);
*vt = atoi(it->current_string);
add_to_vector(self->textures, vt);
free_string_iterator(it);
break;
// f v1/vt1/vn1 v2/vt2/vn2 v3/vt3/vn3 [v*/vt*/vn*]*
case 2:
it = new_string_iterator(point_string, SUB_DELIMITER);
v = malloc(sizeof(int));
vt = malloc(sizeof(int));
vn = malloc(sizeof(int));
if(self->textures == NULL) {
self->textures = new_vector(MINIMAL_POINTS);
}
if(self->normals == NULL) {
self->normals = new_vector(MINIMAL_POINTS);
}
*v = atoi(it->current_string);
add_to_vector(self->vertexes, v);
next_string_iterator(it);
*vn = atoi(it->current_string);
next_string_iterator(it);
// case ?/?/?
if(it->good) {
*vt = *vn;
add_to_vector(self->textures, vt);
*vn = atoi(it->current_string);
// case ?//?
} else {
free(vt);
free_vector(self->textures);
self->textures = NULL;
}
add_to_vector(self->normals, vn);
free_string_iterator(it);
break;
}
}