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https://github.com/Z3Prover/z3
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Add a basic spanning tree
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Anh-Dung Phan
parent
af8da013b5
commit
6ddc838628
4 changed files with 155 additions and 7 deletions
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@ -25,6 +25,7 @@ Revision History:
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#include"trace.h"
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#include"warning.h"
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#include"uint_set.h"
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#include<deque>
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typedef int dl_var;
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@ -953,6 +954,87 @@ public:
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return m_edges;
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}
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void get_neighbours_undirected(dl_var current, svector<dl_var> & neighbours) {
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neighbours.reset();
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edge_id_vector & edges = m_out_edges[current];
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typename edge_id_vector::iterator it = edges.begin(), end = edges.end();
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for (; it != end; ++it) {
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edge_id e_id = *it;
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edge & e = m_edges[e_id];
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if (!e.is_enabled()) continue;
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SASSERT(e.get_source() == current);
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dl_var neighbour = e.get_target();
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neighbours.push_back(neighbour);
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}
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edges = m_in_edges[current];
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it = edges.begin();
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end = edges.end();
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for (; it != end; ++it) {
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edge_id e_id = *it;
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edge & e = m_edges[e_id];
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if (!e.is_enabled()) continue;
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SASSERT(e.get_target() == current);
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dl_var neighbour = e.get_source();
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neighbours.push_back(neighbour);
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}
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}
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void dfs_undirected(dl_var start, svector<dl_var> & threads) {
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threads.reset();
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threads.resize(get_num_nodes());
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uint_set visited;
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svector<dl_var> nodes;
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nodes.push_back(start);
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dl_var prev = -1;
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while(!nodes.empty()) {
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dl_var current = nodes.back();
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nodes.pop_back();
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visited.insert(current);
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if (prev != -1)
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threads[prev] = current;
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prev = current;
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svector<dl_var> neighbours;
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get_neighbours_undirected(current, neighbours);
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for (unsigned i = 0; i < neighbours.size(); ++i) {
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edge_id id;
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SASSERT(prev == -1 || get_edge_id(prev, current, id) || get_edge_id(current, prev, id));
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if (!visited.contains(neighbours[i])) {
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nodes.push_back(neighbours[i]);
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}
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}
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}
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threads[prev] = start;
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}
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void bfs_undirected(dl_var start, svector<dl_var> & parents, svector<dl_var> & depths) {
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parents.reset();
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parents.resize(get_num_nodes());
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depths.reset();
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depths.resize(get_num_nodes());
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uint_set visited;
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std::deque<dl_var> nodes;
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visited.insert(start);
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nodes.push_front(start);
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while(!nodes.empty()) {
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dl_var current = nodes.back();
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nodes.pop_back();
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SASSERT(visited.contains(current));
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svector<dl_var> neighbours;
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get_neighbours_undirected(current, neighbours);
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for (unsigned i = 0; i < neighbours.size(); ++i) {
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dl_var & next = neighbours[i];
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edge_id id;
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SASSERT(get_edge_id(current, next, id) || get_edge_id(next, current, id));
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if (!visited.contains(next)) {
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parents[next] = current;
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depths[next] = depths[current] + 1;
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visited.insert(next);
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nodes.push_front(next);
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}
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}
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}
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}
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template<typename Functor>
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void enumerate_edges(dl_var source, dl_var target, Functor& f) {
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edge_id_vector & edges = m_out_edges[source];
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@ -41,7 +41,7 @@ namespace smt {
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}
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}
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m_step = 0;
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m_tree = alloc(thread_spanning_tree<Ext>, m_graph);
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m_tree = alloc(basic_spanning_tree<Ext>, m_graph);
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}
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template<typename Ext>
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@ -25,8 +25,8 @@ Notes:
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namespace smt {
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template<typename Ext>
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class thread_spanning_tree : public spanning_tree_base, private Ext {
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private:
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class thread_spanning_tree : public spanning_tree_base, protected Ext {
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protected:
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typedef dl_var node;
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typedef dl_edge<Ext> edge;
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typedef dl_graph<Ext> graph;
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@ -57,20 +57,29 @@ namespace smt {
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bool is_ancestor_of(node ancestor, node child);
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public:
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thread_spanning_tree() {};
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thread_spanning_tree(graph & g);
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~thread_spanning_tree() {};
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void initialize(svector<edge_id> const & tree);
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virtual void initialize(svector<edge_id> const & tree);
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void get_descendants(node start, svector<node> & descendants);
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void update(edge_id enter_id, edge_id leave_id);
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virtual void update(edge_id enter_id, edge_id leave_id);
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void get_path(node start, node end, svector<edge_id> & path, svector<bool> & against);
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bool in_subtree_t2(node child);
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bool check_well_formed();
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};
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template<typename Ext>
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class basic_spanning_tree : public thread_spanning_tree<Ext> {
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private:
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graph * m_tree_graph;
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public:
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basic_spanning_tree(graph & g);
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void initialize(svector<edge_id> const & tree);
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void update(edge_id enter_id, edge_id leave_id);
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};
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}
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#endif
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@ -412,6 +412,63 @@ namespace smt {
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SASSERT(children.empty());
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return true;
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}
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// Basic spanning tree
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template<typename Ext>
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basic_spanning_tree<Ext>::basic_spanning_tree(graph & g) : thread_spanning_tree<Ext>(g) {
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}
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template<typename Ext>
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void basic_spanning_tree<Ext>::initialize(svector<edge_id> const & tree) {
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unsigned num_nodes = m_graph.get_num_nodes();
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m_tree_graph = alloc(graph);
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for (unsigned i = 0; i < num_nodes; ++i) {
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m_tree_graph->init_var(i);
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}
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vector<edge> const & es = m_graph.get_all_edges();
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svector<edge_id>::const_iterator it = tree.begin(), end = tree.end();
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for(; it != end; ++it) {
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edge const & e = es[*it];
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m_tree_graph->add_edge(e.get_source(), e.get_target(), e.get_weight(), explanation());
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}
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node root = num_nodes - 1;
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m_tree_graph->bfs_undirected(root, m_pred, m_depth);
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m_tree_graph->dfs_undirected(root, m_thread);
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}
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template<typename Ext>
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void basic_spanning_tree<Ext>::update(edge_id enter_id, edge_id leave_id) {
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if (m_tree_graph)
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dealloc(m_tree_graph);
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m_tree_graph = alloc(graph);
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unsigned num_nodes = m_graph.get_num_nodes();
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for (unsigned i = 0; i < num_nodes; ++i) {
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m_tree_graph->init_var(i);
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}
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vector<edge> const & es = m_graph.get_all_edges();
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svector<edge_id>::const_iterator it = m_tree.begin(), end = m_tree.end();
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for(; it != end; ++it) {
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edge const & e = es[*it];
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if (leave_id != *it) {
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m_tree_graph->add_edge(e.get_source(), e.get_target(), e.get_weight(), explanation());
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}
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}
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m_tree_graph->add_edge(m_graph.get_source(enter_id), m_graph.get_target(enter_id), m_graph.get_weight(enter_id), explanation());
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node root = num_nodes - 1;
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m_tree_graph->bfs_undirected(root, m_pred, m_depth);
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m_tree_graph->dfs_undirected(root, m_thread);
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for (node x = m_thread[root]; x != root; x = m_thread[x]) {
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edge_id id;
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VERIFY(m_graph.get_edge_id(x, m_pred[x], id));
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m_tree[x] = id;
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}
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}
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}
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#endif
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