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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
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@ -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;
}
}