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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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75
src/math/lp/nla_core.cpp
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@ -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