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Merge branch 'polysat' of https://github.com/Z3Prover/z3 into polysat

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This commit is contained in:
Clemens Eisenhofer 2023-02-01 11:28:15 +01:00
commit 783bd60598
5 changed files with 70 additions and 32 deletions
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36
src/math/polysat/conflict.cpp
View file

@ -158,6 +158,7 @@ namespace polysat {
SASSERT(m_vars_occurring.empty());
SASSERT(m_lemmas.empty());
SASSERT(m_narrow_queue.empty());
SASSERT(m_dep.is_null());
}
return is_empty;
}
@ -170,6 +171,7 @@ namespace polysat {
m_lemmas.reset();
m_narrow_queue.reset();
m_level = UINT_MAX;
m_dep = null_dependency;
SASSERT(empty());
}
@ -181,10 +183,11 @@ namespace polysat {
return contains(lit) || contains(~lit);
}
void conflict::init_at_base_level() {
void conflict::init_at_base_level(dependency dep) {
SASSERT(empty());
SASSERT(s.at_base_level());
m_level = s.m_level;
m_dep = dep;
SASSERT(!empty());
// TODO: logger().begin_conflict???
// TODO: check uses of logger().begin_conflict(). sometimes we call it before adding constraints, sometimes after...
@ -303,15 +306,15 @@ namespace polysat {
}
void conflict::add_lemma(char const* name, clause_ref lemma) {
if (!name)
name = "<unknown>";
LOG_H3("Lemma " << name << ": " << show_deref(lemma));
VERIFY(lemma);
for (auto lit : *lemma)
if (s.m_bvars.is_true(lit))
verbose_stream() << "REDUNDANT lemma " << lit << " : " << show_deref(lemma) << "\n";
if (!name)
name = "<unknown>";
LOG_H3("Lemma " << name << ": " << show_deref(lemma));
SASSERT(lemma);
s.m_simplify_clause.apply(*lemma);
lemma->set_redundant(true);
lemma->set_name(name);
@ -434,7 +437,7 @@ namespace polysat {
clause_builder lemma(s);
for (auto c : *this)
for (signed_constraint c : *this)
lemma.insert(~c);
for (unsigned v : m_vars) {
@ -501,6 +504,27 @@ namespace polysat {
}
#endif
void conflict::find_deps(dependency_vector& out_deps) const {
sat::literal_vector todo;
sat::literal_set done;
indexed_uint_set deps;
LOG("conflict: " << *this);
// TODO: starting at literals/variables in the conflict, chase propagations backwards and accumulate dependencies.
verbose_stream() << "WARNING: unsat_core requested but dependency tracking in polysat is TODO\n";
for (signed_constraint c : *this) {
dependency d = s.m_bvars.dep(c.blit());
if (!d.is_null())
deps.insert(d.val());
}
for (unsigned d : deps)
out_deps.push_back(dependency(d));
if (!m_dep.is_null())
out_deps.push_back(m_dep);
}
std::ostream& conflict::display(std::ostream& out) const {
char const* sep = "";
for (auto c : *this)

5
src/math/polysat/conflict.h
View file

@ -101,6 +101,7 @@ namespace polysat {
// Level at which the conflict was discovered
unsigned m_level = UINT_MAX;
dependency m_dep = null_dependency;
public:
conflict(solver& s);
@ -126,7 +127,7 @@ namespace polysat {
bool is_relevant(sat::literal lit) const;
/** conflict due to obvious input inconsistency */
void init_at_base_level();
void init_at_base_level(dependency dep);
/** conflict because the constraint c is false under current variable assignment */
void init(signed_constraint c);
/** boolean conflict with the given clause */
@ -194,6 +195,8 @@ namespace polysat {
/** Move the literals to be narrowed out of the conflict */
sat::literal_vector take_narrow_queue();
void find_deps(dependency_vector& out_deps) const;
std::ostream& display(std::ostream& out) const;
};

23
src/math/polysat/saturation.cpp
View file

@ -1600,8 +1600,7 @@ namespace polysat {
}
/**
* if !x_split: update d such that 0 <= a*x*y0 + b*x + c*y0 + d < M for every value x_min <= x <= x_max
* if x_split: update d such that -M < a*x*y0 + b*x + c*y0 + d < M for every value x_min <= x <= x_max, return x_split such that [x_min,x_split[ and [x_split,x_max] can fit into [0,M[
* Update d such that -M < a*x*y0 + b*x + c*y0 + d < M for every value x_min <= x <= x_max, return x_split such that [x_min,x_split[ and [x_split,x_max] can fit into [0,M[
* return false if there is no such d.
*/
bool saturation::adjust_bound(rational const& x_min, rational const& x_max, rational const& y0, rational const& M, rational const& a, rational const& b, rational const& c, rational& d, rational* x_split) {
@ -1614,14 +1613,22 @@ namespace polysat {
if (max - min >= M)
return false;
// k0 = min k. val + kM >= 0
// = min k. k >= -val/M
// = ceil(-val/M) = -floor(val/M)
rational offset = rational::zero();
#if 0
if (max >= M)
offset = -M * floor(max / M);
else if (max < 0)
offset = M * floor((-max + M - 1) / M);
#else
if (max < 0 || max >= M)
offset = -M * floor(max / M);
#endif
d += offset;
// If min + offset < 0, then [min,max] contained a multiple of M.
// If min + offset < 0, then [min,max] contains a multiple of M.
if (min + offset < 0) {
if (!x_split)
return false;
@ -1735,11 +1742,12 @@ namespace polysat {
VERIFY(x_min <= x_max);
// TODO: d +/- M would suffice here
rational d1 = dd1;
if (a1*x_min*y0 + b1*x_min + c1*y0 + d1 < 0)
d1 += M;
rational d2 = dd2;
VERIFY(adjust_bound(x_min, x_max, y0, M, a1, b1, c1, d1, nullptr));
VERIFY(adjust_bound(x_min, x_max, y0, M, a2, b2, c2, d2, nullptr));
if (a2*x_min*y0 + b2*x_min + c2*y0 + d2 < 0)
d2 += M;
IF_VERBOSE(2,
verbose_stream() << "Adjusted for x in [" << x_min << "; " << x_max << "]\n";
@ -1837,8 +1845,8 @@ namespace polysat {
verbose_stream() << "\n---\n\n";
verbose_stream() << "constraint " << lit_pp(s, a_l_b) << "\n";
verbose_stream() << "x = v" << x << "\n";
s.m_viable.display(verbose_stream(), x) << "\n";
verbose_stream() << "y = v" << y << "\n";
s.m_viable.display(verbose_stream() << "\nx-intervals:\n", x, "\n") << "\n";
verbose_stream() << "\n";
verbose_stream() << "x_min " << x_min << " x_max " << x_max << "\n";
verbose_stream() << "v" << y << " " << y0 << "\n";
@ -1855,6 +1863,7 @@ namespace polysat {
if (x_sp1 > x_sp2)
std::swap(x_sp1, x_sp2);
SASSERT(x_min <= x_sp1 && x_sp1 <= x_sp2 && x_sp2 <= x_max);
IF_VERBOSE(2,
verbose_stream() << "Adjusted\n";

36
src/math/polysat/solver.cpp
View file

@ -158,8 +158,7 @@ namespace polysat {
case l_false:
// Input literal contradicts current boolean state (e.g., opposite literals in the input)
// => conflict only flags the inconsistency
set_conflict_at_base_level();
SASSERT(dep == null_dependency && "track dependencies is TODO");
set_conflict_at_base_level(dep);
return;
case l_true:
// constraint c is already asserted => ignore
@ -174,8 +173,7 @@ namespace polysat {
case l_false:
// asserted an always-false constraint => conflict at base level
LOG("Always false: " << c);
set_conflict_at_base_level();
SASSERT(dep == null_dependency && "track dependencies is TODO");
set_conflict_at_base_level(dep);
return;
case l_true:
// asserted an always-true constraint => ignore
@ -725,9 +723,7 @@ namespace polysat {
/// Verify the value we're trying to assign against the univariate solver
void solver::assign_verify(pvar v, rational val, justification j) {
SASSERT(j.is_decision() || j.is_propagation());
#ifndef NDEBUG
unsigned const old_size = m_search.size();
#endif
signed_constraint c;
clause_ref lemma;
{
@ -748,8 +744,8 @@ namespace polysat {
LOG("Produced lemma: " << show_deref(lemma));
}
}
SASSERT(m_search.size() == old_size);
SASSERT(!m_search.get_assignment().contains(v));
VERIFY_EQ(m_search.size(), old_size);
VERIFY(!m_search.get_assignment().contains(v));
if (lemma) {
add_clause(*lemma);
if (is_conflict()) {
@ -1178,7 +1174,18 @@ namespace polysat {
LOG((clause.is_redundant() ? "Lemma: ": "Aux: ") << clause);
for (sat::literal lit : clause) {
LOG(" " << lit_pp(*this, lit));
// SASSERT(m_bvars.value(lit) != l_true);
if (!m_bvars.is_assigned(lit)) {
switch (lit2cnstr(lit).eval(*this)) {
case l_true:
assign_eval(lit);
break;
case l_false:
assign_eval(~lit);
break;
default:
break;
}
}
// it could be that such a literal has been created previously but we don't detect it when e.g. narrowing a mul_ovfl_constraint
if (m_bvars.value(lit) == l_true) {
// in this case the clause is useless
@ -1229,7 +1236,7 @@ namespace polysat {
clause_ref solver::mk_clause(unsigned n, signed_constraint const* cs, bool is_redundant) {
clause_builder cb(*this);
for (unsigned i = 0; i < n; ++i)
cb.insert_try_eval(cs[i]);
cb.insert(cs[i]);
cb.set_redundant(is_redundant);
return cb.build();
}
@ -1320,14 +1327,9 @@ namespace polysat {
}
void solver::unsat_core(dependency_vector& deps) {
verbose_stream() << "WARNING: unsat_core requested but dependency tracking in polysat is TODO\n";
VERIFY(is_conflict());
deps.reset();
LOG("conflict" << m_conflict);
for (auto c : m_conflict) {
auto d = m_bvars.dep(c.blit());
if (d != null_dependency)
deps.push_back(d);
}
m_conflict.find_deps(deps);
}
std::ostream& solver::display(std::ostream& out) const {

2
src/math/polysat/solver.h
View file

@ -253,7 +253,7 @@ namespace polysat {
void erase_pwatch(pvar v, constraint* c);
void erase_pwatch(constraint* c);
void set_conflict_at_base_level() { m_conflict.init_at_base_level(); }
void set_conflict_at_base_level(dependency dep) { m_conflict.init_at_base_level(dep); }
void set_conflict(signed_constraint c) { m_conflict.init(c); }
void set_conflict(clause& cl) { m_conflict.init(cl); }
void set_conflict_by_viable_interval(pvar v) { m_conflict.init_by_viable_interval(v); }