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move unit propagation into monomial_bounds

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2023-08-31 14:32:05 -07:00
parent c2cbe72b64
commit ff3268e636
4 changed files with 90 additions and 78 deletions
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74
src/math/lp/monomial_bounds.cpp
View file

@ -17,13 +17,14 @@ namespace nla {
common(c),
dep(c->m_intervals.get_dep_intervals()) {}
void monomial_bounds::operator()() {
void monomial_bounds::propagate() {
for (lpvar v : c().m_to_refine) {
monic const& m = c().emons()[v];
propagate(m);
}
}
bool monomial_bounds::is_too_big(mpq const& q) const {
return rational(q).bitsize() > 256;
}
@ -257,5 +258,76 @@ namespace nla {
}
}
void monomial_bounds::unit_propagate() {
for (auto const& m : c().m_emons)
unit_propagate(m);
}
void monomial_bounds::unit_propagate(monic const& m) {
m_propagated.reserve(m.var() + 1, false);
if (m_propagated[m.var()])
return;
if (!is_linear(m))
return;
c().trail().push(set_bitvector_trail(m_propagated, m.var()));
rational k = fixed_var_product(m);
new_lemma lemma(c(), "fixed-values");
if (k == 0) {
for (auto v : m) {
if (c().var_is_fixed(v) && c().val(v).is_zero()) {
lemma.explain_fixed(v);
break;
}
}
lemma |= ineq(m.var(), lp::lconstraint_kind::EQ, 0);
}
else {
for (auto v : m)
if (c().var_is_fixed(v))
lemma.explain_fixed(v);
lpvar w = non_fixed_var(m);
SASSERT(w != null_lpvar);
lp::lar_term term;
term.add_monomial(-m.rat_sign(), m.var());
term.add_monomial(k, w);
lemma |= ineq(term, lp::lconstraint_kind::EQ, 0);
}
}
bool monomial_bounds::is_linear(monic const& m) {
unsigned non_fixed = 0;
for (lpvar v : m) {
if (!c().var_is_fixed(v))
++non_fixed;
else if (c().val(v).is_zero())
return true;
}
return non_fixed <= 1;
}
rational monomial_bounds::fixed_var_product(monic const& m) {
rational r(1);
for (lpvar v : m) {
if (c().var_is_fixed(v))
r *= c().lra.get_column_value(v).x;
}
return r;
}
lpvar monomial_bounds::non_fixed_var(monic const& m) {
for (lpvar v : m)
if (!c().var_is_fixed(v))
return v;
return null_lpvar;
}
}

13
src/math/lp/monomial_bounds.h
View file

@ -16,6 +16,8 @@ namespace nla {
class core;
class monomial_bounds : common {
dep_intervals& dep;
void var2interval(lpvar v, scoped_dep_interval& i);
bool is_too_big(mpq const& q) const;
bool propagate_down(monic const& m, lpvar u);
@ -27,8 +29,17 @@ namespace nla {
void analyze_monomial(monic const& m, unsigned& num_free, lpvar& free_v, unsigned& power) const;
bool is_free(lpvar v) const;
bool is_zero(lpvar v) const;
// monomial propagation
bool_vector m_propagated;
void unit_propagate(monic const& m);
bool is_linear(monic const& m);
rational fixed_var_product(monic const& m);
lpvar non_fixed_var(monic const& m);
public:
monomial_bounds(core* core);
void operator()();
void propagate();
void unit_propagate();
};
}

75
src/math/lp/nla_core.cpp
View file

@ -1546,7 +1546,7 @@ lbool core::check(vector<ineq>& lits, vector<lemma>& l_vec) {
auto no_effect = [&]() { return !done() && l_vec.empty() && lits.empty(); };
if (no_effect())
m_monomial_bounds();
m_monomial_bounds.propagate();
if (no_effect() && improve_bounds())
return l_false;
@ -1814,79 +1814,14 @@ bool core::improve_bounds() {
void core::propagate(vector<lemma>& lemmas) {
// disable for now
return;
// propagate linear monomials
// propagate linear monomials
lemmas.reset();
m_lemma_vec = &lemmas;
for (auto const& m : m_emons)
propagate(m, lemmas);
m_monomial_bounds.unit_propagate();
}
void core::propagate(monic const& m, vector<lemma>& lemmas) {
m_propagated.reserve(m.var() + 1, false);
if (m_propagated[m.var()])
return;
if (!is_linear(m))
return;
trail().push(set_bitvector_trail(m_propagated, m.var()));
rational k = fixed_var_product(m);
new_lemma lemma(*this, "fixed-values");
if (k == 0) {
for (auto v : m) {
if (var_is_fixed(v) && val(v).is_zero()) {
lemma.explain_fixed(v);
break;
}
}
lemma |= ineq(m.var(), lp::lconstraint_kind::EQ, 0);
}
else {
for (auto v : m)
if (var_is_fixed(v))
lemma.explain_fixed(v);
lpvar w = non_fixed_var(m);
SASSERT(w != null_lpvar);
lp::lar_term term;
term.add_monomial(mpq(-1), m.var());
term.add_monomial(k, w);
lemma |= ineq(term, lp::lconstraint_kind::EQ, 0);
}
}
bool core::is_linear(monic const& m) {
unsigned non_fixed = 0;
for (lpvar v : m) {
if (!var_is_fixed(v))
++non_fixed;
else if (val(v).is_zero())
return true;
}
return non_fixed <= 1;
}
rational core::fixed_var_product(monic const& m) {
rational r(1);
for (lpvar v : m) {
if (var_is_fixed(v))
r *= lra.get_column_value(v).x;
}
return r;
}
lpvar core::non_fixed_var(monic const& m) {
for (lpvar v : m)
if (!var_is_fixed(v))
return v;
return null_lpvar;
}
} // end of nla

6
src/math/lp/nla_core.h
View file

@ -436,12 +436,6 @@ private:
void save_tableau();
bool integrality_holds();
// monomial propagation
bool_vector m_propagated;
void propagate(monic const& m, vector<lemma>& lemmas);
bool is_linear(monic const& m);
rational fixed_var_product(monic const& m);
lpvar non_fixed_var(monic const& m);
}; // end of core