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add option to reduce pseudo-linear monomials

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2025-09-04 11:03:58 -07:00
parent 6eee8688c2
commit 98a9a34f2b
5 changed files with 65 additions and 27 deletions
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52
src/math/lp/nla_core.cpp
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@ -1307,6 +1307,10 @@ lbool core::check() {
if (no_effect())
m_monomial_bounds.propagate();
if (no_effect() && refine_pseudo_linear())
return l_false;
{
std::function<void(void)> check1 = [&]() { if (no_effect() && run_horner) m_horner.horner_lemmas(); };
@ -1519,6 +1523,54 @@ void core::simplify() {
}
bool core::is_pseudo_linear(monic const& m) const {
bool has_unbounded = false;
for (auto v : m.vars()) {
if (lra.column_is_bounded(v) && lra.var_is_int(v)) {
auto lb = lra.get_lower_bound(v);
auto ub = lra.get_upper_bound(v);
if (ub - lb <= rational(4))
continue;
}
if (has_unbounded)
return false;
has_unbounded = true;
}
return true;
}
bool core::refine_pseudo_linear() {
if (!params().arith_nl_reduce_pseudo_linear())
return false;
for (lpvar j : m_to_refine) {
if (is_pseudo_linear(m_emons[j])) {
refine_pseudo_linear(m_emons[j]);
return true;
}
}
return false;
}
void core::refine_pseudo_linear(monic const& m) {
lemma_builder lemma(*this, "nla-pseudo-linear");
lpvar nlvar = null_lpvar;
rational prod(1);
for (auto v : m.vars()) {
if (lra.column_is_bounded(v) && lra.var_is_int(v)) {
auto lb = lra.get_lower_bound(v);
auto ub = lra.get_upper_bound(v);
if (ub - lb <= rational(4)) {
lemma |= ineq(v, llc::NE, val(v));
prod *= val(v);
continue;
}
}
SASSERT(nlvar == null_lpvar);
nlvar = v;
}
lemma |= ineq(lp::lar_term(m.var(), rational(-prod), nlvar), llc::EQ, rational(0));
// lemma.display(verbose_stream() << "pseudo-linear lemma\n");
}