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sketch of internal propagation

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2023-09-27 20:40:55 -07:00
parent 9033b826f4
commit 7207f0ff9c
10 changed files with 87 additions and 77 deletions
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2
src/math/lp/lar_solver.h
View file

@ -142,7 +142,9 @@ class lar_solver : public column_namer {
void insert_to_columns_with_changed_bounds(unsigned j);
void update_column_type_and_bound_check_on_equal(unsigned j, const mpq& right_side, constraint_index ci, unsigned&);
void update_column_type_and_bound(unsigned j, const mpq& right_side, constraint_index ci);
public:
void update_column_type_and_bound(unsigned j, lconstraint_kind kind, const mpq& right_side, u_dependency* dep);
private:
void update_column_type_and_bound_with_ub(var_index j, lconstraint_kind kind, const mpq& right_side, u_dependency* dep);
void update_column_type_and_bound_with_no_ub(var_index j, lconstraint_kind kind, const mpq& right_side, u_dependency* dep);
void update_bound_with_ub_lb(var_index j, lconstraint_kind kind, const mpq& right_side, u_dependency* dep);

78
src/math/lp/monomial_bounds.cpp
View file

@ -274,45 +274,47 @@ namespace nla {
c().m_emons.set_propagated(m);
rational k = fixed_var_product(m);
if (k == 0) {
ineq ineq(m.var(), lp::lconstraint_kind::EQ, 0);
if (c().ineq_holds(ineq))
return;
lpvar zero_var = find<monic,lpvar>(m, [&](lpvar v) { return c().var_is_fixed(v) && c().val(v).is_zero(); });
IF_VERBOSE(2, verbose_stream() << "zero " << m.var() << "\n");
new_lemma lemma(c(), "fixed-values");
lemma.explain_fixed(zero_var);
lemma |= ineq;
}
else {
lpvar w = non_fixed_var(m);
lp::lar_term term;
term.add_monomial(m.rat_sign(), m.var());
if (w != null_lpvar) {
IF_VERBOSE(2, verbose_stream() << "linear " << m.var() << " " << k << " " << w << "\n");
term.add_monomial(-k, w);
k = 0;
}
else
IF_VERBOSE(2, verbose_stream() << "fixed " << m.var() << " " << k << "\n");
ineq ineq(term, lp::lconstraint_kind::EQ, k);
if (c().ineq_holds(ineq))
return;
new_lemma lemma(c(), "linearized-fixed-values");
for (auto v : m)
if (c().var_is_fixed(v))
lemma.explain_fixed(v);
lemma |= ineq;
}
lpvar w = non_fixed_var(m);
if (w == null_lpvar)
propagate_fixed(m, k);
else
propagate_nonfixed(m, k, w);
}
void monomial_bounds::propagate_fixed(monic const& m, rational const& k) {
auto* dep = explain_fixed(m, k);
c().lra.update_column_type_and_bound(m.var(), lp::lconstraint_kind::EQ, k, dep);
}
void monomial_bounds::propagate_nonfixed(monic const& m, rational const& k, lpvar w) {
vector<std::pair<lp::mpq, unsigned>> coeffs;
coeffs.push_back(std::make_pair(-k, w));
coeffs.push_back(std::make_pair(rational::one(), m.var()));
lp::lpvar term_index = c().lra.add_term(coeffs, UINT_MAX);
auto* dep = explain_fixed(m, k);
term_index = c().lra.map_term_index_to_column_index(term_index);
c().lra.update_column_type_and_bound(term_index, lp::lconstraint_kind::EQ, k, dep);
}
u_dependency* monomial_bounds::explain_fixed(monic const& m, rational const& k) {
u_dependency* dep = nullptr;
for (auto j : m.vars()) {
if (k == 0) {
if (c().var_is_fixed_to_zero(j)) {
dep = c().lra.dep_manager().mk_join(dep, c().lra.get_column_lower_bound_witness(j));
dep = c().lra.dep_manager().mk_join(dep, c().lra.get_column_upper_bound_witness(j));
return dep;
}
continue;
}
if (c().var_is_fixed(j)) {
dep = c().lra.dep_manager().mk_join(dep, c().lra.get_column_lower_bound_witness(j));
dep = c().lra.dep_manager().mk_join(dep, c().lra.get_column_upper_bound_witness(j));
}
}
return dep;
}
bool monomial_bounds::is_linear(monic const& m) {
unsigned non_fixed = 0;

3
src/math/lp/monomial_bounds.h
View file

@ -25,6 +25,9 @@ namespace nla {
bool propagate_value(dep_interval& range, lpvar v, unsigned power);
void compute_product(unsigned start, monic const& m, scoped_dep_interval& i);
bool propagate(monic const& m);
void propagate_fixed(monic const& m, rational const& k);
void propagate_nonfixed(monic const& m, rational const& k, lpvar w);
u_dependency* explain_fixed(monic const& m, rational const& k);
bool propagate_down(monic const& m, dep_interval& mi, lpvar v, unsigned power, dep_interval& product);
void analyze_monomial(monic const& m, unsigned& num_free, lpvar& free_v, unsigned& power) const;
bool is_free(lpvar v) const;

26
src/math/lp/nla_core.cpp
View file

@ -809,7 +809,7 @@ void core::print_stats(std::ostream& out) {
void core::clear() {
m_lemmas.clear();
m_literal_vec->clear();
m_literals.clear();
}
void core::init_search() {
@ -1494,12 +1494,12 @@ void core::check_weighted(unsigned sz, std::pair<unsigned, std::function<void(vo
}
lbool core::check_power(lpvar r, lpvar x, lpvar y) {
m_lemmas.reset();
clear();
return m_powers.check(r, x, y, m_lemmas);
}
void core::check_bounded_divisions() {
m_lemmas.reset();
clear();
m_divisions.check_bounded_divisions();
}
// looking for a free variable inside of a monic to split
@ -1511,18 +1511,17 @@ void core::add_bounds() {
for (lpvar j : m.vars()) {
if (!var_is_free(j)) continue;
// split the free variable (j <= 0, or j > 0), and return
m_literal_vec->push_back(ineq(j, lp::lconstraint_kind::EQ, rational::zero()));
m_literals.push_back(ineq(j, lp::lconstraint_kind::EQ, rational::zero()));
++lp_settings().stats().m_nla_bounds;
return;
}
}
}
lbool core::check(vector<ineq>& lits) {
lbool core::check() {
lp_settings().stats().m_nla_calls++;
TRACE("nla_solver", tout << "calls = " << lp_settings().stats().m_nla_calls << "\n";);
lra.get_rid_of_inf_eps();
m_literal_vec = &lits;
if (!(lra.get_status() == lp::lp_status::OPTIMAL ||
lra.get_status() == lp::lp_status::FEASIBLE)) {
TRACE("nla_solver", tout << "unknown because of the lra.m_status = " << lra.get_status() << "\n";);
@ -1542,7 +1541,7 @@ lbool core::check(vector<ineq>& lits) {
bool run_bounded_nlsat = should_run_bounded_nlsat();
bool run_bounds = params().arith_nl_branching();
auto no_effect = [&]() { return !done() && m_lemmas.empty() && lits.empty(); };
auto no_effect = [&]() { return !done() && m_lemmas.empty() && m_literals.empty(); };
if (no_effect())
m_monomial_bounds.propagate();
@ -1560,7 +1559,7 @@ lbool core::check(vector<ineq>& lits) {
{1, check2},
{1, check3} };
check_weighted(3, checks);
if (!m_lemmas.empty() || !lits.empty())
if (!m_lemmas.empty() || !m_literals.empty())
return l_false;
}
@ -1639,9 +1638,8 @@ lbool core::bounded_nlsat() {
m_nlsat_fails = 0;
m_nlsat_delay /= 2;
}
if (ret == l_true) {
m_lemmas.reset();
}
if (ret == l_true)
clear();
return ret;
}
@ -1655,10 +1653,10 @@ bool core::no_lemmas_hold() const {
return true;
}
lbool core::test_check() {
vector<ineq> lits;
lra.set_status(lp::lp_status::OPTIMAL);
return check(lits);
return check();
}
std::ostream& core::print_terms(std::ostream& out) const {
@ -1811,7 +1809,7 @@ bool core::improve_bounds() {
}
void core::propagate() {
m_lemmas.reset();
clear();
m_monomial_bounds.unit_propagate();
}

9
src/math/lp/nla_core.h
View file

@ -86,8 +86,8 @@ class core {
smt_params_helper m_params;
std::function<bool(lpvar)> m_relevant;
vector<lemma> m_lemmas;
vector<ineq> * m_literal_vec = nullptr;
indexed_uint_set m_to_refine;
vector<ineq> m_literals;
indexed_uint_set m_to_refine;
tangents m_tangents;
basics m_basics;
order m_order;
@ -386,7 +386,7 @@ public:
bool conflict_found() const;
lbool check(vector<ineq>& ineqs);
lbool check();
lbool check_power(lpvar r, lpvar x, lpvar y);
void check_bounded_divisions();
@ -428,7 +428,8 @@ public:
void set_use_nra_model(bool m);
bool use_nra_model() const { return m_use_nra_model; }
void collect_statistics(::statistics&);
vector<nla::lemma> const& lemmas() const { return m_lemmas; }
vector<nla::lemma> const& lemmas() const { return m_lemmas; }
vector<nla::ineq> const& literals() const { return m_literals; }
private:
void restore_patched_values();
void constrain_nl_in_tableau();

8
src/math/lp/nla_solver.cpp
View file

@ -42,8 +42,8 @@ namespace nla {
bool solver::need_check() { return m_core->has_relevant_monomial(); }
lbool solver::check(vector<ineq>& lits) {
return m_core->check(lits);
lbool solver::check() {
return m_core->check();
}
void solver::propagate() {
@ -104,4 +104,8 @@ namespace nla {
vector<nla::lemma> const& solver::lemmas() const {
return m_core->lemmas();
}
vector<nla::ineq> const& solver::literals() const {
return m_core->literals();
}
}

3
src/math/lp/nla_solver.h
View file

@ -36,7 +36,7 @@ namespace nla {
void push();
void pop(unsigned scopes);
bool need_check();
lbool check(vector<ineq>& lits);
lbool check();
void propagate();
lbool check_power(lpvar r, lpvar x, lpvar y);
bool is_monic_var(lpvar) const;
@ -48,5 +48,6 @@ namespace nla {
nlsat::anum const& am_value(lp::var_index v) const;
void collect_statistics(::statistics & st);
vector<nla::lemma> const& lemmas() const;
vector<nla::ineq> const& literals() const;
};
}

4
src/sat/smt/arith_solver.cpp
View file

@ -1416,7 +1416,7 @@ namespace arith {
}
void solver::assume_literals() {
for (auto const& ineq : m_nla_literals) {
for (auto const& ineq : m_nla->literals()) {
auto lit = mk_ineq_literal(ineq);
ctx.mark_relevant(lit);
s().set_phase(lit);
@ -1459,7 +1459,7 @@ namespace arith {
return l_true;
m_a1 = nullptr; m_a2 = nullptr;
lbool r = m_nla->check(m_nla_literals);
lbool r = m_nla->check();
switch (r) {
case l_false:
assume_literals();

1
src/sat/smt/arith_solver.h
View file

@ -248,7 +248,6 @@ namespace arith {
// lemmas
lp::explanation m_explanation;
vector<nla::ineq> m_nla_literals;
literal_vector m_core, m_core2;
vector<rational> m_coeffs;
svector<enode_pair> m_eqs;

30
src/smt/theory_lra.cpp
View file

@ -1602,8 +1602,7 @@ public:
case l_true:
return FC_DONE;
case l_false:
for (const nla::lemma & l : m_nla->lemmas())
false_case_of_check_nla(l);
add_lemmas();
return FC_CONTINUE;
case l_undef:
return FC_GIVEUP;
@ -1800,8 +1799,7 @@ public:
if (!m_nla)
return true;
m_nla->check_bounded_divisions();
for (auto & lemma : m_nla->lemmas())
false_case_of_check_nla(lemma);
add_lemmas();
return m_nla->lemmas().empty();
}
@ -2000,7 +1998,7 @@ public:
// create term >= 0 (or term <= 0)
atom = mk_bound(ineq.term(), ineq.rs(), is_lower);
return literal(ctx().get_bool_var(atom), pos);
}
}
void false_case_of_check_nla(const nla::lemma & l) {
m_lemma = l; //todo avoid the copy
@ -2021,14 +2019,11 @@ public:
final_check_status check_nla_continue() {
m_a1 = nullptr; m_a2 = nullptr;
lbool r = m_nla->check(m_nla_literals);
lbool r = m_nla->check();
switch (r) {
case l_false:
for (const nla::ineq& i : m_nla_literals)
assume_literal(i);
for (const nla::lemma & l : m_nla->lemmas())
false_case_of_check_nla(l);
add_lemmas();
return FC_CONTINUE;
case l_true:
return assume_eqs()? FC_CONTINUE: FC_DONE;
@ -2158,10 +2153,16 @@ public:
}
void propagate_nla() {
if (!m_nla)
return;
m_nla->propagate();
for (nla::lemma const& l : m_nla->lemmas())
if (m_nla) {
m_nla->propagate();
add_lemmas();
}
}
void add_lemmas() {
for (const nla::ineq& i : m_nla->literals())
assume_literal(i);
for (const nla::lemma & l : m_nla->lemmas())
false_case_of_check_nla(l);
}
@ -3191,7 +3192,6 @@ public:
}
lp::explanation m_explanation;
vector<nla::ineq> m_nla_literals;
literal_vector m_core;
svector<enode_pair> m_eqs;
vector<parameter> m_params;