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trim

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2022-10-05 05:43:48 +02:00
parent f8ca692dee
commit 4e780d0cc8
3 changed files with 116 additions and 75 deletions
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48
src/cmd_context/extra_cmds/proof_cmds.cpp
View file

@ -189,7 +189,9 @@ class proof_trim {
cmd_context& ctx;
ast_manager& m;
sat::proof_trim trim;
vector<expr_ref_vector> m_clauses;
bool_vector m_is_infer;
void mk_clause(expr_ref_vector const& clause) {
trim.init_clause();
for (expr* arg: clause)
@ -214,9 +216,11 @@ public:
trim(gparams::get_module("sat"), m.limit()) {
}
void assume(expr_ref_vector const& _clause, bool is_initial = true) {
mk_clause(_clause);
trim.assume(true);
void assume(expr_ref_vector const& clause) {
mk_clause(clause);
trim.assume(m_clauses.size());
m_clauses.push_back(clause);
m_is_infer.push_back(false);
}
void del(expr_ref_vector const& _clause) {
@ -224,14 +228,42 @@ public:
trim.del();
}
void infer(expr_ref_vector const& _clause, app*) {
mk_clause(_clause);
trim.infer();
void infer(expr_ref_vector const& clause, app* hint) {
mk_clause(clause);
trim.infer(m_clauses.size());
m_clauses.push_back(clause);
if (hint)
m_clauses.back().push_back(hint);
m_is_infer.push_back(true);
}
void updt_params(params_ref const& p) {
trim.updt_params(p);
}
}
void do_trim(std::ostream& out) {
ast_pp_util pp(m);
auto ids = trim.trim();
for (unsigned id : ids) {
auto const& clause = m_clauses[id];
bool is_infer = m_is_infer[id];
for (expr* e : clause)
pp.collect(e);
pp.display_decls(out);
for (expr* e : clause)
pp.define_expr(out, e);
if (!is_infer)
out << "(assume ";
else
out << "(infer";
for (expr* e : clause)
pp.display_expr_def(out << " ", e);
out << ")\n";
}
}
};
class proof_saver {

132
src/sat/sat_proof_trim.cpp
View file

@ -29,12 +29,13 @@ namespace sat {
Output: reduced trail - result
*/
vector<literal_vector> proof_trim::trim() {
vector<literal_vector> result;
unsigned_vector proof_trim::trim() {
unsigned_vector result;
m_core_literals.reset();
m_core_literals.insert(literal_vector());
m_propagated.resize(num_vars(), false);
for (unsigned i = m_trail.size(); i-- > 0; ) {
auto const& [cl, clp, is_add, is_initial] = m_trail[i];
auto const& [id, cl, clp, is_add, is_initial] = m_trail[i];
if (!is_add) {
revive(cl, clp);
continue;
@ -43,7 +44,7 @@ namespace sat {
del(cl, clp);
if (!in_core(cl, clp))
continue;
result.push_back(cl);
result.push_back(id);
if (is_initial)
continue;
conflict_analysis_core(cl, clp);
@ -73,15 +74,15 @@ namespace sat {
(l1 == cl[2] && l2 == cl[0] && l3 == cl[1]));
}
/**
* cl is on the trail if there is some literal l that is implied by cl
* Remove all clauses after cl that are in the cone of influence of cl.
* The coi is defined inductively: C is in coi of cl if it contains ~l
* or it contains ~l' where l' is implied by a clause in the coi of cl.
* Possible optimization:
* - check if clause contains a literal that is on implied on the trail
* if it doesn't contain any such literal, bypass the trail adjustment.
*/
/**
* cl is on the trail if there is some literal l that is implied by cl
* Remove all clauses after cl that are in the cone of influence of cl.
* The coi is defined inductively: C is in coi of cl if it contains ~l
* or it contains ~l' where l' is implied by a clause in the coi of cl.
* Possible optimization:
* - check if clause contains a literal that is on implied on the trail
* if it doesn't contain any such literal, bypass the trail adjustment.
*/
void proof_trim::prune_trail(literal_vector const& cl, clause* cp) {
m_in_clause.reset();
@ -89,6 +90,12 @@ namespace sat {
for (literal lit : cl)
m_in_clause.insert(lit.index());
auto unassign_literal = [&](literal l) {
m_in_coi.insert((~l).index());
s.m_assignment[l.index()] = l_undef;
s.m_assignment[(~l).index()] = l_undef;
};
bool on_trail = false;
unsigned j = 0;
@ -97,9 +104,7 @@ namespace sat {
if (m_in_clause.contains(l.index())) {
SASSERT(!on_trail);
on_trail = true;
m_in_coi.insert((~l).index());
s.m_assignment[l.index()] = l_undef;
s.m_assignment[(~l).index()] = l_undef;
unassign_literal(l);
continue;
}
if (!on_trail) {
@ -119,11 +124,8 @@ namespace sat {
else
UNREACHABLE(); // approach does not work for external justifications
if (in_coi) {
m_in_coi.insert((~l).index());
s.m_assignment[l.index()] = l_undef;
s.m_assignment[(~l).index()] = l_undef;
}
if (in_coi)
unassign_literal(l);
else
s.m_trail[j++] = s.m_trail[i];
}
@ -171,52 +173,59 @@ namespace sat {
s.propagate(false);
}
SASSERT(s.inconsistent());
auto add_dependency = [&](literal lit) {
bool_var v = lit.var();
if (s.lvl(v) == 0) {
// inefficient for repeated insertions ?
auto j = s.m_justification[v];
literal lit = literal(v, s.value(v) == l_false);
add_core(lit, j);
}
else if (s.lvl(v) == 2)
s.mark(v);
};
auto add_jdependency = [&](justification j) {
switch (j.get_kind()) {
case justification::BINARY:
add_dependency(j.get_literal());
break;
case justification::TERNARY:
add_dependency(j.get_literal1());
add_dependency(j.get_literal2());
break;
case justification::CLAUSE:
for (auto lit : s.get_clause(j))
if (s.value(lit) == l_false)
add_dependency(lit);
break;
default:
break;
}
};
for (unsigned i = trail_size0; i < s.m_trail.size(); ++i)
m_propagated[s.m_trail[i].var()] = true;
if (s.m_not_l != null_literal)
add_dependency(s.m_not_l);
add_jdependency(s.m_conflict);
add_dependency(s.m_conflict);
for (unsigned i = s.m_trail.size(); i-- > trail_size0; ) {
bool_var v = s.m_trail[i].var();
m_propagated[v] = false;
if (!s.is_marked(v))
continue;
s.reset_mark(v);
add_jdependency(s.m_justification[v]);
add_dependency(s.get_justification(v));
}
s.pop(2);
}
void proof_trim::add_dependency(literal lit) {
bool_var v = lit.var();
if (m_propagated[v]) // literal was propagated after assuming ~C
s.mark(v);
else if (s.lvl(v) == 0) { // literal depends on level 0, it is not assumed by ~C
// inefficient for repeated insertions ?
auto j = s.get_justification(v);
literal lit = literal(v, s.value(v) == l_false);
add_core(lit, j);
}
}
void proof_trim::add_dependency(justification j) {
switch (j.get_kind()) {
case justification::BINARY:
add_dependency(j.get_literal());
break;
case justification::TERNARY:
add_dependency(j.get_literal1());
add_dependency(j.get_literal2());
break;
case justification::CLAUSE:
for (auto lit : s.get_clause(j))
if (s.value(lit) == l_false)
add_dependency(lit);
break;
case justification::EXT_JUSTIFICATION:
UNREACHABLE();
break;
default:
break;
}
}
void proof_trim::add_core(literal l, justification j) {
m_clause.reset();
switch (j.get_kind()) {
@ -256,7 +265,6 @@ namespace sat {
s.mk_clause(cl, status::redundant());
}
clause* proof_trim::del(literal_vector const& cl) {
clause* cp = nullptr;
IF_VERBOSE(3, verbose_stream() << "del: " << cl << "\n");
@ -283,19 +291,17 @@ namespace sat {
IF_VERBOSE(3, verbose_stream() << "add: " << *cl << "\n");
auto& v = m_clauses.insert_if_not_there(lits, clause_vector());
v.push_back(cl);
}
}
proof_trim::proof_trim(params_ref const& p, reslimit& lim):
s(p, lim)
{}
void proof_trim::assume(bool is_initial) {
void proof_trim::assume(unsigned id, bool is_initial) {
std::sort(m_clause.begin(), m_clause.end());
IF_VERBOSE(3, verbose_stream() << "add: " << m_clause << "\n");
auto* cl = s.mk_clause(m_clause, status::redundant());
m_trail.push_back({ m_clause, cl, true, is_initial });
m_trail.push_back({ id, m_clause, cl, true, is_initial });
s.propagate(false);
save(m_clause, cl);
}
@ -303,11 +309,11 @@ namespace sat {
void proof_trim::del() {
std::sort(m_clause.begin(), m_clause.end());
clause* cp = del(m_clause);
m_trail.push_back({ m_clause, cp, false, true });
m_trail.push_back({ 0, m_clause, cp, false, true });
}
void proof_trim::infer() {
assume(false);
void proof_trim::infer(unsigned id) {
assume(id, false);
}

11
src/sat/sat_proof_trim.h
View file

@ -33,7 +33,7 @@ namespace sat {
literal_vector m_clause;
uint_set m_in_clause;
uint_set m_in_coi;
vector<std::tuple<literal_vector, clause*, bool, bool>> m_trail;
vector<std::tuple<unsigned, literal_vector, clause*, bool, bool>> m_trail;
struct hash {
@ -49,6 +49,7 @@ namespace sat {
map<literal_vector, clause_vector, hash, eq> m_clauses;
hashtable<literal_vector, hash, eq> m_core_literals;
bool_vector m_propagated;
void del(literal_vector const& cl, clause* cp);
@ -57,6 +58,8 @@ namespace sat {
void prune_trail(literal_vector const& cl, clause* cp);
void conflict_analysis_core(literal_vector const& cl, clause* cp);
void add_dependency(literal lit);
void add_dependency(justification j);
void add_core(literal l, justification j);
bool in_core(literal_vector const& cl, clause* cp) const;
void revive(literal_vector const& cl, clause* cp);
@ -73,12 +76,12 @@ namespace sat {
void add_literal(bool_var v, bool sign) { m_clause.push_back(literal(v, sign)); }
unsigned num_vars() { return s.num_vars(); }
void assume(bool is_initial = true);
void assume(unsigned id, bool is_initial = true);
void del();
void infer();
void infer(unsigned id);
void updt_params(params_ref const& p) { s.updt_params(p); }
vector<literal_vector> trim();
unsigned_vector trim();
};
}