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add facility to check for missing propagations

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This commit is contained in:
Nikolaj Bjorner 2023-10-15 20:33:48 -07:00
parent cafe3acff1
commit bdac86501d
5 changed files with 109 additions and 11 deletions
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42
src/math/lp/nla_grobner.cpp
View file

@ -61,6 +61,9 @@ namespace nla {
}
// DEBUG_CODE(for (auto e : m_solver.equations()) check_missing_propagation(*e););
if (m_quota > 0)
--m_quota;
@ -125,11 +128,11 @@ namespace nla {
typedef lp::lar_term term;
bool grobner::propagate_fixed(const dd::solver::equation& eq) {
dd::pdd const& p = eq.poly();
//IF_VERBOSE(0, verbose_stream() << p << "\n");
if (p.is_unary()) {
unsigned v = p.var();
if (c().var_is_fixed(v))
return false;
ineq new_eq(v, llc::EQ, rational::zero());
if (c().ineq_holds(new_eq))
return false;
@ -147,12 +150,19 @@ namespace nla {
rational d = lcm(denominator(a), denominator(b));
a *= d;
b *= d;
#if 0
c().lra.update_column_type_and_bound(v, lp::lconstraint_kind::EQ, b/a, eq.dep());
lp::explanation exp;
explain(eq, exp);
c().add_fixed_equality(c().lra.column_to_reported_index(v), b/a, exp);
#else
ineq new_eq(term(a, v), llc::EQ, b);
if (c().ineq_holds(new_eq))
return false;
new_lemma lemma(c(), "pdd-eq");
add_dependencies(lemma, eq);
lemma |= new_eq;
#endif
return true;
}
@ -193,15 +203,19 @@ namespace nla {
return true;
}
void grobner::add_dependencies(new_lemma& lemma, const dd::solver::equation& eq) {
lp::explanation ex;
void grobner::explain(const dd::solver::equation& eq, lp::explanation& exp) {
u_dependency_manager dm;
vector<unsigned, false> lv;
dm.linearize(eq.dep(), lv);
for (unsigned ci : lv)
ex.push_back(ci);
lemma &= ex;
exp.push_back(ci);
}
void grobner::add_dependencies(new_lemma& lemma, const dd::solver::equation& eq) {
lp::explanation exp;
explain(eq, exp);
lemma &= exp;
}
void grobner::configure() {
@ -280,6 +294,10 @@ namespace nla {
}
bool grobner::is_conflicting(const dd::solver::equation& e) {
for (auto j : e.poly().free_vars())
if (lra.column_is_free(j))
return false;
auto& di = c().m_intervals.get_dep_intervals();
dd::pdd_interval eval(di);
eval.var2interval() = [this](lpvar j, bool deps, scoped_dep_interval& a) {
@ -549,4 +567,16 @@ namespace nla {
tout << "\n");
}
void grobner::check_missing_propagation(const dd::solver::equation& e) {
vector<dd::pdd> eqs;
eqs.push_back(e.poly());
lbool r = c().m_nra.check(eqs);
CTRACE("grobner", r == l_false, m_solver.display(tout << "missed conflict ", e););
if (r != l_true)
return;
r = c().m_nra.check_tight(e.poly());
CTRACE("grobner", r == l_false, m_solver.display(tout << "tight equality ", e););
}
}

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

@ -41,6 +41,9 @@ namespace nla {
bool propagate_factorization(const dd::solver::equation& eq);
void add_dependencies(new_lemma& lemma, const dd::solver::equation& eq);
void explain(const dd::solver::equation& eq, lp::explanation& exp);
void check_missing_propagation(const dd::solver::equation& eq);
// setup
void configure();

66
src/math/lp/nra_solver.cpp
View file

@ -206,14 +206,62 @@ struct solver::imp {
}
}
if (r == l_true)
return r;
IF_VERBOSE(0, verbose_stream() << "check-nra " << r << "\n";
m_nlsat->display(verbose_stream());
for (auto const& [v, w] : m_lp2nl) {
auto& ls = m_nla_core.lra;
if (ls.column_has_lower_bound(v))
verbose_stream() << w << " >= " << ls.get_lower_bound(v) << "\n";
verbose_stream() << "x" << w << " >= " << ls.get_lower_bound(v) << "\n";
if (ls.column_has_upper_bound(v))
verbose_stream() << w << " <= " << ls.get_upper_bound(v) << "\n";
verbose_stream() << "x" << w << " <= " << ls.get_upper_bound(v) << "\n";
});
return r;
}
lbool check_tight(dd::pdd const& eq) {
m_zero = nullptr;
m_nlsat = alloc(nlsat::solver, m_limit, m_params, false);
m_zero = alloc(scoped_anum, am());
m_lp2nl.reset();
m_term_set.reset();
add_eq(eq);
for (auto const& [v, w] : m_lp2nl) {
auto& ls = m_nla_core.lra;
if (ls.column_has_lower_bound(v))
add_strict_lb(ls.get_lower_bound(v), w);
if (ls.column_has_upper_bound(v))
add_strict_ub(ls.get_upper_bound(v), w);
}
lbool r = l_undef;
try {
r = m_nlsat->check();
}
catch (z3_exception&) {
if (m_limit.is_canceled()) {
r = l_undef;
}
else {
throw;
}
}
if (r == l_true)
return r;
IF_VERBOSE(0, verbose_stream() << "check-nra tight " << r << "\n";
m_nlsat->display(verbose_stream());
for (auto const& [v, w] : m_lp2nl) {
auto& ls = m_nla_core.lra;
if (ls.column_has_lower_bound(v))
verbose_stream() << "x" << w << " >= " << ls.get_lower_bound(v) << "\n";
if (ls.column_has_upper_bound(v))
verbose_stream() << "x" << w << " <= " << ls.get_upper_bound(v) << "\n";
});
@ -235,6 +283,13 @@ struct solver::imp {
m_nlsat->mk_clause(1, &lit, nullptr);
}
void add_strict_lb(lp::impq const& b, unsigned w) {
add_bound(b.x, w, false, nlsat::atom::kind::GT);
}
void add_strict_ub(lp::impq const& b, unsigned w) {
add_bound(b.x, w, false, nlsat::atom::kind::LT);
}
void add_lb(lp::impq const& b, unsigned w) {
add_bound(b.x, w, b.y <= 0, b.y > 0 ? nlsat::atom::kind::GT : nlsat::atom::kind::LT);
}
@ -269,7 +324,8 @@ struct solver::imp {
m_lp2nl.insert(v, w);
}
polynomial::polynomial_ref vp(pm.mk_polynomial(w, 1), pm);
return pm.add(lo, pm.mul(vp, hi));
polynomial::polynomial_ref mp(pm.mul(vp, hi), pm);
return pm.add(lo, mp);
}
bool is_int(lp::var_index v) {
@ -361,6 +417,10 @@ lbool solver::check(vector<dd::pdd> const& eqs) {
return m_imp->check(eqs);
}
lbool solver::check_tight(dd::pdd const& eq) {
return m_imp->check_tight(eq);
}
bool solver::need_check() {
return m_imp->need_check();
}

7
src/math/lp/nra_solver.h
View file

@ -38,10 +38,15 @@ namespace nra {
lbool check();
/**
\breif Check feasibility of equalities modulo bounds constraints on their variables.
\brief Check feasibility of equalities modulo bounds constraints on their variables.
*/
lbool check(vector<dd::pdd> const& eqs);
/**
\brief Check if equality is tight.
*/
lbool check_tight(const dd::pdd& eq);
/*
\brief determine whether nra check is needed.
*/

2
src/smt/theory_lra.cpp
View file

@ -2158,7 +2158,6 @@ public:
if (m_nla) {
m_nla->propagate();
add_lemmas();
add_equalities();
lp().collect_more_rows_for_lp_propagation();
}
}
@ -2193,6 +2192,7 @@ public:
assume_literal(i);
for (const nla::lemma & l : m_nla->lemmas())
false_case_of_check_nla(l);
add_equalities();
}
bool should_propagate() const {