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move fixed variable propagation to nla_core/monomial_bounds

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This commit is contained in:
Nikolaj Bjorner 2025-01-13 18:18:53 -08:00
parent f3e7c8c9df
commit c01336553e
4 changed files with 62 additions and 54 deletions
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50
src/math/lp/monomial_bounds.cpp
View file

@ -16,7 +16,15 @@ namespace nla {
monomial_bounds::monomial_bounds(core* c):
common(c),
dep(c->m_intervals.get_dep_intervals()) {}
dep(c->m_intervals.get_dep_intervals()) {
std::function<void(lpvar v)> fixed_eh = [&](lpvar v) {
c->trail().push(push_back_vector(m_fixed_var_trail));
m_fixed_var_trail.push_back(v);
};
// uncomment to enable:
// c->lra.m_fixed_var_eh = fixed_eh;
}
void monomial_bounds::propagate() {
for (lpvar v : c().m_to_refine) {
@ -24,6 +32,46 @@ namespace nla {
if (add_lemma())
break;
}
propagate_fixed_vars();
}
void monomial_bounds::propagate_fixed_vars() {
if (m_fixed_var_qhead == m_fixed_var_trail.size())
return;
c().trail().push(value_trail(m_fixed_var_qhead));
while (m_fixed_var_qhead < m_fixed_var_trail.size())
propagate_fixed_var(m_fixed_var_trail[m_fixed_var_qhead++]);
}
void monomial_bounds::propagate_fixed_var(lpvar v) {
SASSERT(c().var_is_fixed(v));
TRACE("nla_solver", tout << "propagate fixed var: " << c().var_str(v) << "\n";);
for (auto const& m : c().emons().get_use_list(v))
propagate_fixed_var(m, v);
}
void monomial_bounds::propagate_fixed_var(monic const& m, lpvar v) {
unsigned num_free = 0;
lpvar free_var = null_lpvar;
for (auto w : m)
if (!c().var_is_fixed(w))
++num_free, free_var = w;
if (num_free != 1)
return;
u_dependency* d = nullptr;
auto& lra = c().lra;
lp::mpq coeff(1);
for (auto w : m) {
if (c().var_is_fixed(w)) {
d = lra.join_deps(d, lra.join_deps(lra.get_column_lower_bound_witness(w), lra.get_column_upper_bound_witness(w)));
coeff += lra.get_column_value(w).x;
}
}
vector<std::pair<lp::mpq, lpvar>> coeffs;
coeffs.push_back({coeff, free_var});
coeffs.push_back({mpq(-1), v});
lpvar j = lra.add_term(coeffs, UINT_MAX);
lra.update_column_type_and_bound(j, llc::EQ, mpq(0), d);
}
bool monomial_bounds::is_too_big(mpq const& q) const {

7
src/math/lp/monomial_bounds.h
View file

@ -43,6 +43,13 @@ namespace nla {
bool is_linear(monic const& m, lpvar& w, lpvar & fixed_to_zero);
rational fixed_var_product(monic const& m, lpvar w);
lpvar non_fixed_var(monic const& m);
// fixed variable propagation
unsigned m_fixed_var_qhead = 0;
unsigned_vector m_fixed_var_trail;
void propagate_fixed_vars();
void propagate_fixed_var(lpvar v);
void propagate_fixed_var(monic const& m, lpvar v);
public:
monomial_bounds(core* core);
void propagate();

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

@ -100,11 +100,15 @@ class core {
nra::solver m_nra;
bool m_cautious_patching = true;
lpvar m_patched_var = 0;
monic const* m_patched_monic = nullptr;
monic const* m_patched_monic = nullptr;
void check_weighted(unsigned sz, std::pair<unsigned, std::function<void(void)>>* checks);
void add_bounds();
public:
// constructor
core(lp::lar_solver& s, params_ref const& p, reslimit&);

53
src/smt/theory_lra.cpp
View file

@ -254,45 +254,6 @@ class theory_lra::imp {
return add_const(0, is_int ? m_zero_var : m_rzero_var, is_int);
}
svector<theory_var> m_fixed_vars;
unsigned m_fixed_vars_head = 0;
bool propagate_fixed_vars() {
if (m_fixed_vars_head == m_fixed_vars.size())
return false;
ctx().push_trail(value_trail(m_fixed_vars_head));
bool propagated = false;
while (m_fixed_vars_head < m_fixed_vars.size()) {
theory_var v = m_fixed_vars[m_fixed_vars_head++];
enode* n = th.get_enode(v);
for (enode* p : n->get_parents()) {
expr* e = p->get_expr();
expr* x, * y;
if (!a.is_mul(e, x, y))
continue;
if (a.is_numeral(x) || a.is_numeral(y))
continue;
if (x == n->get_expr())
std::swap(x, y);
if (y != n->get_expr())
continue;
// comment out to enable propagation:
continue;
expr_ref k(a.mk_numeral(get_value(v), a.is_int(y)), m);
literal eq1 = th.mk_eq(y, k, false);
literal eq2 = th.mk_eq(e, a.mk_mul(x, k), false);
ctx().mk_th_axiom(get_id(), ~eq1, eq2);
// v2 could perform propagation directly
// v3 could consider multiplication of more than two variables.
// such as e := x * y * z. If both x, y become fixed we have e = z * value(x) * value(y)
// verbose_stream() << mk_bounded_pp(e, m) << " - " << mk_bounded_pp(n->get_expr(), m) << "\n";
}
}
return propagated;
}
void ensure_nla() {
if (!m_nla) {
m_nla = alloc(nla::solver, *m_solver.get(), ctx().get_params(), m.limit());
@ -913,18 +874,6 @@ public:
lp().settings().int_run_gcd_test() = ctx().get_fparams().m_arith_gcd_test;
lp().settings().set_random_seed(ctx().get_fparams().m_random_seed);
m_lia = alloc(lp::int_solver, *m_solver.get());
std::function<void(lpvar)> new_fixed = [&](lpvar v) {
theory_var u = lp().local_to_external(v);
if (u == null_theory_var)
return;
expr* var = th.get_expr(u);
if (a.is_numeral(var))
return;
m_fixed_vars.push_back(u);
ctx().push_trail(push_back_vector(m_fixed_vars));
};
lp().m_fixed_var_eh = new_fixed;
}
void internalize_is_int(app * n) {
@ -2135,7 +2084,7 @@ public:
}
bool propagate() {
return process_atoms() && propagate_core() && propagate_fixed_vars();
return process_atoms() && propagate_core();
}
bool propagate_core() {