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Fix bugs on candidate list pivot rule

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Anh-Dung Phan 2013-11-11 18:23:21 -08:00
parent 0d6ffe6b31
commit 66eda866ca
2 changed files with 57 additions and 43 deletions
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76
src/smt/network_flow.h
View file

@ -156,24 +156,29 @@ namespace smt {
private: private:
edge_id m_next_edge; edge_id m_next_edge;
svector<edge_id> m_candidates; svector<edge_id> m_candidates;
unsigned num_candidates; unsigned m_num_candidates;
unsigned m_minor_step;
unsigned m_current_length;
static const unsigned NUM_CANDIDATES = 10; static const unsigned NUM_CANDIDATES = 10;
static const unsigned MINOR_STEP_LIMIT = 5;
public: public:
candidate_list_pivot(graph & g, vector<numeral> & potentials, candidate_list_pivot(graph & g, vector<numeral> & potentials,
svector<edge_state> & states, edge_id & enter_id) : svector<edge_state> & states, edge_id & enter_id) :
pivot_rule_impl(g, potentials, states, enter_id), pivot_rule_impl(g, potentials, states, enter_id),
m_next_edge(0), m_next_edge(0),
num_candidates(NUM_CANDIDATES), m_minor_step(0),
m_candidates(num_candidates) { m_current_length(0),
m_num_candidates(NUM_CANDIDATES),
m_candidates(m_num_candidates) {
} }
bool choose_entering_edge() { bool choose_entering_edge() {
if (m_candidates.empty()) { if (m_current_length == 0 || m_minor_step == MINOR_STEP_LIMIT) {
// Build the candidate list // Build the candidate list
unsigned num_edges = m_graph.get_num_edges(); unsigned num_edges = m_graph.get_num_edges();
numeral max = numeral::zero(); numeral max = numeral::zero();
unsigned count = 0; m_current_length = 0;
for (unsigned i = m_next_edge; i < m_next_edge + num_edges; ++i) { for (unsigned i = m_next_edge; i < m_next_edge + num_edges; ++i) {
edge_id id = (i >= num_edges) ? i - num_edges : i; edge_id id = (i >= num_edges) ? i - num_edges : i;
node src = m_graph.get_source(id); node src = m_graph.get_source(id);
@ -181,16 +186,18 @@ namespace smt {
if (m_states[id] != BASIS) { if (m_states[id] != BASIS) {
numeral cost = m_potentials[src] - m_potentials[tgt] - m_graph.get_weight(id); numeral cost = m_potentials[src] - m_potentials[tgt] - m_graph.get_weight(id);
if (cost.is_pos()) { if (cost.is_pos()) {
m_candidates[count++] = id; m_candidates[m_current_length] = id;
++m_current_length;
if (cost > max) { if (cost > max) {
max = cost; max = cost;
m_enter_id = id; m_enter_id = id;
} }
} }
if (count >= num_candidates) break; if (m_current_length >= m_num_candidates) break;
} }
} }
m_next_edge = m_enter_id; m_next_edge = m_enter_id;
m_minor_step = 1;
if (max.is_pos()) { if (max.is_pos()) {
TRACE("network_flow", { TRACE("network_flow", {
tout << "Found entering edge " << m_enter_id << " between node "; tout << "Found entering edge " << m_enter_id << " between node ";
@ -202,36 +209,37 @@ namespace smt {
TRACE("network_flow", tout << "Found no entering edge...\n";); TRACE("network_flow", tout << "Found no entering edge...\n";);
return false; return false;
} }
else {
numeral max = numeral::zero(); ++m_minor_step;
unsigned last = m_candidates.size(); numeral max = numeral::zero();
for (unsigned i = 0; i < last; ++i) { for (unsigned i = 0; i < m_current_length; ++i) {
edge_id id = m_candidates[i]; edge_id id = m_candidates[i];
node src = m_graph.get_source(id); node src = m_graph.get_source(id);
node tgt = m_graph.get_target(id); node tgt = m_graph.get_target(id);
if (m_states[id] != BASIS) { if (m_states[id] != BASIS) {
numeral cost = m_potentials[src] - m_potentials[tgt] - m_graph.get_weight(id); numeral cost = m_potentials[src] - m_potentials[tgt] - m_graph.get_weight(id);
if (cost > max) { if (cost > max) {
max = cost; max = cost;
m_enter_id = id; m_enter_id = id;
} }
// Remove stale candidates // Remove stale candidates
if (!cost.is_pos()) { if (!cost.is_pos()) {
m_candidates[i] = m_candidates[--last]; --m_current_length;
} m_candidates[i] = m_candidates[m_current_length];
--i;
} }
} }
if (max.is_pos()) {
TRACE("network_flow", {
tout << "Found entering edge " << m_enter_id << " between node ";
tout << m_graph.get_source(m_enter_id) << " and node " << m_graph.get_target(m_enter_id);
tout << " with reduced cost = " << max << "...\n";
});
return true;
}
TRACE("network_flow", tout << "Found no entering edge...\n";);
return false;
} }
if (max.is_pos()) {
TRACE("network_flow", {
tout << "Found entering edge " << m_enter_id << " between node ";
tout << m_graph.get_source(m_enter_id) << " and node " << m_graph.get_target(m_enter_id);
tout << " with reduced cost = " << max << "...\n";
});
return true;
}
TRACE("network_flow", tout << "Found no entering edge...\n";);
return false;
}; };
}; };

24
src/smt/spanning_tree_def.h
View file

@ -333,23 +333,29 @@ namespace smt {
SASSERT(m_pred[q] == v); SASSERT(m_pred[q] == v);
SASSERT(is_preorder_traversal(v, get_final(v))); SASSERT(is_preorder_traversal(v, get_final(v)));
node prev = find_rev_thread(v); node prev = find_rev_thread(v);
node final_q = get_final(q); node f_q = get_final(q);
node final_v = get_final(v); node f_v = get_final(v);
node next = m_thread[final_v]; node next = m_thread[f_v];
node alpha = find_rev_thread(q); node alpha = find_rev_thread(q);
if (final_q == final_v) { if (f_q == f_v) {
m_thread[final_q] = v; SASSERT(f_q != v && alpha != next);
m_thread[f_q] = v;
m_thread[alpha] = next; m_thread[alpha] = next;
f_q = alpha;
} }
else { else {
node beta = m_thread[final_q]; node beta = m_thread[f_q];
m_thread[final_q] = v; SASSERT(f_q != v && alpha != beta);
m_thread[f_q] = v;
m_thread[alpha] = beta; m_thread[alpha] = beta;
f_q = f_v;
} }
SASSERT(prev != q);
m_thread[prev] = q; m_thread[prev] = q;
m_pred[v] = q; m_pred[v] = q;
SASSERT(is_preorder_traversal(q, get_final(q))); // Notes: f_q has to be used since m_depth hasn't been updated yet.
SASSERT(is_preorder_traversal(q, f_q));
} }
/** /**