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fix bug in PB constraint init_watch handling, adding transitive reduction, HLE, ULT,

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2017-12-01 08:23:55 -08:00
parent 427b5ef002
commit 018411bc58
10 changed files with 248 additions and 136 deletions
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120
src/sat/sat_scc.cpp
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@ -234,17 +234,7 @@ namespace sat {
return to_elim.size();
}
// shuffle vertices to obtain different DAG traversal each time
void scc::shuffle(literal_vector& lits) {
unsigned sz = lits.size();
if (sz > 1) {
for (unsigned i = sz; i-- > 0; ) {
std::swap(lits[i], lits[m_rand(i+1)]);
}
}
}
vector<literal_vector> const& scc::get_big(bool learned) {
void scc::init_big(bool learned) {
unsigned num_lits = m_solver.num_vars() * 2;
m_dag.reset();
m_roots.reset();
@ -263,53 +253,21 @@ namespace sat {
edges.push_back(v);
}
}
shuffle(edges);
shuffle<literal>(edges.size(), edges.c_ptr(), m_rand);
}
return m_dag;
init_dfs_num(learned);
}
void scc::get_dfs_num(bool learned) {
unsigned num_lits = m_solver.num_vars() * 2;
SASSERT(m_left.size() == num_lits);
SASSERT(m_right.size() == num_lits);
literal_vector todo;
// retrieve literals that have no predecessors
for (unsigned l_idx = 0; l_idx < num_lits; l_idx++) {
literal u(to_literal(l_idx));
if (m_roots[u.index()]) todo.push_back(u);
}
shuffle(todo);
int dfs_num = 0;
while (!todo.empty()) {
literal u = todo.back();
int& d = m_left[u.index()];
// already visited
if (d > 0) {
if (m_right[u.index()] < 0) {
m_right[u.index()] = dfs_num;
}
todo.pop_back();
}
// visited as child:
else if (d < 0) {
d = -d;
for (literal v : m_dag[u.index()]) {
if (m_left[v.index()] == 0) {
m_left[v.index()] = - d - 1;
m_root[v.index()] = m_root[u.index()];
m_parent[v.index()] = u;
todo.push_back(v);
}
}
}
// new root.
else {
d = --dfs_num;
}
}
}
struct scc::pframe {
literal m_parent;
literal m_child;
pframe(literal p, literal c):
m_parent(p), m_child(c) {}
literal child() const { return m_child; }
literal parent() const { return m_parent; }
};
unsigned scc::reduce_tr(bool learned) {
void scc::init_dfs_num(bool learned) {
unsigned num_lits = m_solver.num_vars() * 2;
m_left.reset();
m_right.reset();
@ -317,11 +275,61 @@ namespace sat {
m_parent.reset();
m_left.resize(num_lits, 0);
m_right.resize(num_lits, -1);
m_root.resize(num_lits, null_literal);
m_parent.resize(num_lits, null_literal);
for (unsigned i = 0; i < num_lits; ++i) {
m_root[i] = to_literal(i);
m_parent[i] = to_literal(i);
}
get_dfs_num(learned);
svector<pframe> todo;
// retrieve literals that have no predecessors
for (unsigned l_idx = 0; l_idx < num_lits; l_idx++) {
literal u(to_literal(l_idx));
if (m_roots[u.index()]) {
todo.push_back(pframe(null_literal, u));
}
}
shuffle<pframe>(todo.size(), todo.c_ptr(), m_rand);
int dfs_num = 0;
while (!todo.empty()) {
literal u = todo.back().child();
if (m_left[u.index()] > 0) {
// already visited
if (m_right[u.index()] < 0) {
m_right[u.index()] = ++dfs_num;
}
todo.pop_back();
}
else {
SASSERT(m_left[u.index()] == 0);
m_left[u.index()] = ++dfs_num;
for (literal v : m_dag[u.index()]) {
if (m_left[v.index()] == 0) {
todo.push_back(pframe(u, v));
}
}
literal p = todo.back().parent();
if (p != null_literal) {
m_root[u.index()] = m_root[p.index()];
m_parent[u.index()] = p;
}
}
}
for (unsigned i = 0; i < num_lits; ++i) {
if (m_right[i] < 0) {
VERIFY(m_left[i] == 0);
m_left[i] = ++dfs_num;
m_right[i] = ++dfs_num;
}
}
for (unsigned i = 0; i < num_lits; ++i) {
VERIFY(m_left[i] < m_right[i]);
}
}
unsigned scc::reduce_tr(bool learned) {
unsigned num_lits = m_solver.num_vars() * 2;
init_big(learned);
unsigned idx = 0;
unsigned elim = m_num_elim_bin;
for (watch_list & wlist : m_solver.m_watches) {
@ -333,7 +341,7 @@ namespace sat {
watched& w = *it;
if (learned ? w.is_binary_learned_clause() : w.is_binary_unblocked_clause()) {
literal v = w.get_literal();
if (m_left[u.index()] + 1 < m_left[v.index()]) {
if (reaches(u, v) && u != get_parent(v)) {
++m_num_elim_bin;
}
else {