flowtype Graph<captype,tcaptype,flowtype>::maxflow(bool reuse_trees, Block<node_id>* _changed_list)
{
node *i, *j, *current_node = NULL;
arc *a;
nodeptr *np, *np_next;
if (!nodeptr_block)
{
nodeptr_block = new DBlock<nodeptr>(NODEPTR_BLOCK_SIZE, error_function);
}
changed_list = _changed_list;
if (maxflow_iteration == 0 && reuse_trees) { if (error_function) (*error_function)("reuse_trees cannot be used in the first call to maxflow()!"); exit(1); }
if (changed_list && !reuse_trees) { if (error_function) (*error_function)("changed_list cannot be used without reuse_trees!"); exit(1); }
if (reuse_trees) maxflow_reuse_trees_init();
else maxflow_init();
// main loop
while ( 1 )
{
// test_consistency(current_node);
if ((i=current_node))
{
i -> next = NULL; /* remove active flag */
if (!i->parent) i = NULL;
}
if (!i)
{
if (!(i = next_active())) break;
}
/* growth */
if (!i->is_sink)
{
/* grow source tree */
for (a=i->first; a; a=a->next)
if (a->r_cap)
{
j = a -> head;
if (!j->parent)
{
j -> is_sink = 0;
j -> parent = a -> sister;
j -> TS = i -> TS;
j -> DIST = i -> DIST + 1;
set_active(j);
add_to_changed_list(j);
}
else if (j->is_sink) break;
else if (j->TS <= i->TS &&
j->DIST> i->DIST)
{
/* heuristic - trying to make the distance from j to the source shorter */
j -> parent = a -> sister;
j -> TS = i -> TS;
j -> DIST = i -> DIST + 1;
}
}
}
else
{
/* grow sink tree */
for (a=i->first; a; a=a->next)
if (a->sister->r_cap)
{
j = a -> head;
if (!j->parent)
{
j -> is_sink = 1;
j -> parent = a -> sister;
j -> TS = i -> TS;
j -> DIST = i -> DIST + 1;
set_active(j);
add_to_changed_list(j);
}
else if (!j->is_sink) { a = a -> sister; break; }
else if (j->TS <= i->TS &&
j->DIST> i->DIST)
{
/* heuristic - trying to make the distance from j to the sink shorter */
j -> parent = a -> sister;
j -> TS = i -> TS;
j -> DIST = i -> DIST + 1;
}
}
}
TIME ++;
if (a)
{
i -> next = i; /* set active flag */
current_node = i;
/* augmentation */
augment(a);
/* augmentation end */
/* adoption */
while ((np=orphan_first))
{
np_next = np -> next;
np -> next = NULL;
while ((np=orphan_first))
{
orphan_first = np -> next;
i = np -> ptr;
nodeptr_block -> Delete(np);
if (!orphan_first) orphan_last = NULL;
if (i->is_sink) process_sink_orphan(i);
else process_source_orphan(i);
}
orphan_first = np_next;
}
/* adoption end */
}
else current_node = NULL;
}
// test_consistency();
if (!reuse_trees || (maxflow_iteration % 64) == 0)
{
delete nodeptr_block;
nodeptr_block = NULL;
}
maxflow_iteration ++;
return flow;
}
void Graph<captype,tcaptype,flowtype>::maxflow_reuse_trees_init()
{
node* i;
node* j;
node* queue = queue_first[1];
arc* a;
nodeptr* np;
queue_first[0] = queue_last[0] = NULL;
queue_first[1] = queue_last[1] = NULL;
orphan_first = orphan_last = NULL;
TIME ++;
while ((i=queue))
{
queue = i->next;
if (queue == i) queue = NULL;
i->next = NULL;
i->is_marked = 0;
set_active(i);
if (i->tr_cap == 0)
{
if (i->parent) set_orphan_rear(i);
continue;
}
if (i->tr_cap> 0)
{
if (!i->parent || i->is_sink)
{
i->is_sink = 0;
for (a=i->first; a; a=a->next)
{
j = a->head;
if (!j->is_marked)
{
if (j->parent == a->sister) set_orphan_rear(j);
if (j->parent && j->is_sink && a->r_cap> 0) set_active(j);
}
}
add_to_changed_list(i);
}
}
else
{
if (!i->parent || !i->is_sink)
{
i->is_sink = 1;
for (a=i->first; a; a=a->next)
{
j = a->head;
if (!j->is_marked)
{
if (j->parent == a->sister) set_orphan_rear(j);
if (j->parent && !j->is_sink && a->sister->r_cap> 0) set_active(j);
}
}
add_to_changed_list(i);
}
}
i->parent = TERMINAL;
i -> TS = TIME;
i -> DIST = 1;
}
//test_consistency();
/* adoption */
while ((np=orphan_first))
{
orphan_first = np -> next;
i = np -> ptr;
nodeptr_block -> Delete(np);
if (!orphan_first) orphan_last = NULL;
if (i->is_sink) process_sink_orphan(i);
else process_source_orphan(i);
}
/* adoption end */
//test_consistency();
}
void Graph<captype,tcaptype,flowtype>::process_sink_orphan(node *i)
{
node *j;
arc *a0, *a0_min = NULL, *a;
int d, d_min = INFINITE_D;
/* trying to find a new parent */
for (a0=i->first; a0; a0=a0->next)
if (a0->r_cap)
{
j = a0 -> head;
if (j->is_sink && (a=j->parent))
{
/* checking the origin of j */
d = 0;
while ( 1 )
{
if (j->TS == TIME)
{
d += j -> DIST;
break;
}
a = j -> parent;
d ++;
if (a==TERMINAL)
{
j -> TS = TIME;
j -> DIST = 1;
break;
}
if (a==ORPHAN) { d = INFINITE_D; break; }
j = a -> head;
}
if (d<INFINITE_D) /* j originates from the sink - done */
{
if (d<d_min)
{
a0_min = a0;
d_min = d;
}
/* set marks along the path */
for (j=a0->head; j->TS!=TIME; j=j->parent->head)
{
j -> TS = TIME;
j -> DIST = d --;
}
}
}
}
if (i->parent = a0_min)
{
i -> TS = TIME;
i -> DIST = d_min + 1;
}
else
{
/* no parent is found */
add_to_changed_list(i);
/* process neighbors */
for (a0=i->first; a0; a0=a0->next)
{
j = a0 -> head;
if (j->is_sink && (a=j->parent))
{
if (a0->r_cap) set_active(j);
if (a!=TERMINAL && a!=ORPHAN && a->head==i)
{
set_orphan_rear(j); // add j to the end of the adoption list
}
}
}
}
}
void QPBO<REAL>::maxflow_reuse_trees_init()
{
Node* i;
Node* j;
Node* queue = queue_first[1];
Arc* a;
nodeptr* np;
queue_first[0] = queue_last[0] = NULL;
queue_first[1] = queue_last[1] = NULL;
orphan_first = orphan_last = NULL;
TIME ++;
while ((i=queue))
{
queue = i->next;
if (queue == i) queue = NULL;
if (IsNode0(i))
{
if (i->is_removed) continue;
}
else
{
if (GetMate1(i)->is_removed) continue;
}
i->next = NULL;
i->is_marked = 0;
set_active(i);
if (i->tr_cap == 0)
{
if (i->parent) set_orphan_rear(i);
continue;
}
if (i->tr_cap > 0)
{
if (!i->parent || i->is_sink)
{
i->is_sink = 0;
for (a=i->first; a; a=a->next)
{
j = a->head;
if (!j->is_marked)
{
if (j->parent == a->sister) set_orphan_rear(j);
if (j->parent && j->is_sink && a->r_cap > 0) set_active(j);
}
}
add_to_changed_list(i);
}
}
else
{
if (!i->parent || !i->is_sink)
{
i->is_sink = 1;
for (a=i->first; a; a=a->next)
{
j = a->head;
if (!j->is_marked)
{
if (j->parent == a->sister) set_orphan_rear(j);
if (j->parent && !j->is_sink && a->sister->r_cap > 0) set_active(j);
}
}
add_to_changed_list(i);
}
}
i->parent = QPBO_MAXFLOW_TERMINAL;
i -> TS = TIME;
i -> DIST = 1;
}
code_assert(stage == 1);
//test_consistency();
/* adoption */
while ((np=orphan_first))
{
orphan_first = np -> next;
i = np -> ptr;
nodeptr_block -> Delete(np);
if (!orphan_first) orphan_last = NULL;
if (i->is_sink) process_sink_orphan(i);
else process_source_orphan(i);
}
/* adoption end */
//test_consistency();
}
