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move linear cell construction to levelwise

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Valentin Promies 2026-02-20 16:01:06 +01:00
parent 6d3f3f2c35
commit 95afda383c
5 changed files with 119 additions and 205 deletions
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77
src/nlsat/levelwise.cpp
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@ -73,6 +73,8 @@ namespace nlsat {
mutable std_vector<unsigned> m_deg_in_order_graph; // degree of polynomial in resultant graph
mutable std_vector<unsigned> m_unique_neighbor; // UINT_MAX = not set, UINT_MAX-1 = multiple
bool m_linear_cell = false; // indicates whether cell bounds are forced to be linear
assignment const& sample() const { return m_solver.sample(); }
// Utility: call fn for each distinct irreducible factor of poly
@ -245,7 +247,8 @@ namespace nlsat {
assignment const&,
pmanager& pm,
anum_manager& am,
polynomial::cache& cache)
polynomial::cache& cache,
bool linear)
: m_solver(solver),
m_P(ps),
m_n(max_x),
@ -254,7 +257,8 @@ namespace nlsat {
m_cache(cache),
m_todo(m_cache, true),
m_level_ps(m_pm),
m_psc_tmp(m_pm) {
m_psc_tmp(m_pm),
m_linear_cell(linear) {
m_I.reserve(m_n);
for (unsigned i = 0; i < m_n; ++i)
m_I.emplace_back(m_pm);
@ -994,6 +998,66 @@ namespace nlsat {
}
}
void mk_linear_poly_from_root(anum const& a, polynomial_ref& p) {
rational r;
m_am.to_rational(a, r);
p = m_pm.mk_polynomial(m_level);
p = denominator(r)*p - numerator(r);
}
// Ensure that the interval bounds will be described by linear polynomials.
// If this is not already the case, the working set of polynomials is extended by
// new linear polynomials whose roots under-approximate the cell boundary.
// Based on: Valentin Promies, Jasper Nalbach, Erika Abraham and Paul Wagner
// "More is Less: Adding Polynomials for Faster Explanations in NLSAT" (CADE30, 2025)
void add_linear_approximations(anum const& v) {
polynomial_ref p_lower(m_pm), p_upper(m_pm);
auto& r = m_rel.m_rfunc;
if (m_I[m_level].is_section()) {
if (!m_am.is_rational(v)) {
// TODO: FAIL
NOT_IMPLEMENTED_YET();
}
else if (m_pm.total_degree(m_I[m_level].l) > 1) {
mk_linear_poly_from_root(v, p_lower);
// add p_lower and according i.r.e. to relevant places
m_I[m_level].l = p_lower;
m_I[m_level].l_index = 1;
m_level_ps.push_back(p_lower);
r.emplace((r.begin() + m_l_rf), m_am, p_lower, 1, v, m_level_ps.size()-1);
m_poly_has_roots.push_back(true);
}
return;
}
// sector: have to consider lower and upper bound
if (!m_I[m_level].l_inf() && m_pm.total_degree(m_I[m_level].l) > 1) {
scoped_anum between(m_am);
m_am.select(r[m_l_rf].val, v, between);
mk_linear_poly_from_root(between, p_lower);
// add p_lower and according i.r.e. to relevant places
m_I[m_level].l = p_lower;
m_I[m_level].l_index = 1;
m_level_ps.push_back(p_lower);
r.emplace((r.begin() + m_l_rf + 1), m_am, p_lower, 1, between, m_level_ps.size()-1);
m_poly_has_roots.push_back(true);
++m_l_rf;
++m_u_rf;
}
if (!m_I[m_level].u_inf() && m_pm.total_degree(m_I[m_level].u) > 1) {
scoped_anum between(m_am);
m_am.select(v, r[m_u_rf].val, between);
mk_linear_poly_from_root(between, p_upper);
// add p_lower and according i.r.e. to relevant places
m_I[m_level].u = p_upper;
m_I[m_level].u_index = 1;
m_level_ps.push_back(p_lower);
r.emplace((r.begin() + m_u_rf), m_am, p_upper, 1, between, m_level_ps.size()-1);
m_poly_has_roots.push_back(true);
}
}
// Build Θ (root functions) and pick I_level around sample(level).
// Sets m_l_rf/m_u_rf and m_I[level].
// Returns whether any roots were found (i.e., whether a relation can be built).
@ -1009,6 +1073,10 @@ namespace nlsat {
return false;
set_interval_from_root_partition(v, mid);
if (m_linear_cell)
add_linear_approximations(v);
compute_side_mask();
return true;
}
@ -1360,8 +1428,9 @@ namespace nlsat {
assignment const& s,
pmanager& pm,
anum_manager& am,
polynomial::cache& cache)
: m_impl(new impl(solver, ps, n, s, pm, am, cache)) {}
polynomial::cache& cache,
bool linear)
: m_impl(new impl(solver, ps, n, s, pm, am, cache, linear)) {}
levelwise::~levelwise() { delete m_impl; }