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move bounded division lemmas to nla solver/ nla_divisions.

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This commit is contained in:
Nikolaj Bjorner 2023-01-30 11:11:04 -08:00
parent 03ca330926
commit 304b316314
7 changed files with 110 additions and 216 deletions
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130
src/smt/theory_lra.cpp
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@ -62,7 +62,6 @@ class theory_lra::imp {
struct scope {
unsigned m_bounds_lim;
unsigned m_idiv_lim;
unsigned m_asserted_qhead;
unsigned m_asserted_atoms_lim;
};
@ -161,7 +160,6 @@ class theory_lra::imp {
svector<delayed_atom> m_asserted_atoms;
ptr_vector<expr> m_not_handled;
ptr_vector<app> m_underspecified;
ptr_vector<expr> m_idiv_terms;
vector<ptr_vector<api_bound> > m_use_list; // bounds where variables are used.
// attributes for incremental version:
@ -436,19 +434,23 @@ class theory_lra::imp {
}
else if (a.is_idiv(n, n1, n2)) {
if (!a.is_numeral(n2, r) || r.is_zero()) found_underspecified(n);
m_idiv_terms.push_back(n);
app_ref mod(a.mk_mod(n1, n2), m);
ctx().internalize(mod, false);
if (ctx().relevancy()) ctx().add_relevancy_dependency(n, mod);
#if 1
if (m_nla && !a.is_numeral(n2)) {
// shortcut to create non-linear division axioms.
theory_var r = mk_var(n);
theory_var q = mk_var(n);
theory_var x = mk_var(n1);
theory_var y = mk_var(n2);
m_nla->add_idivision(get_lpvar(n), get_lpvar(n1), get_lpvar(n2));
}
#endif
m_nla->add_idivision(register_theory_var_in_lar_solver(q), register_theory_var_in_lar_solver(x), register_theory_var_in_lar_solver(y));
}
if (a.is_numeral(n2) && a.is_bounded(n1)) {
ensure_nla();
theory_var q = mk_var(n);
theory_var x = mk_var(n1);
theory_var y = mk_var(n2);
m_nla->add_bounded_division(register_theory_var_in_lar_solver(q), register_theory_var_in_lar_solver(x), register_theory_var_in_lar_solver(y));
}
}
else if (a.is_mod(n, n1, n2)) {
if (!a.is_numeral(n2, r) || r.is_zero()) found_underspecified(n);
@ -1077,7 +1079,6 @@ public:
scope& sc = m_scopes.back();
sc.m_bounds_lim = m_bounds_trail.size();
sc.m_asserted_qhead = m_asserted_qhead;
sc.m_idiv_lim = m_idiv_terms.size();
sc.m_asserted_atoms_lim = m_asserted_atoms.size();
lp().push();
if (m_nla)
@ -1092,7 +1093,6 @@ public:
}
unsigned old_size = m_scopes.size() - num_scopes;
del_bounds(m_scopes[old_size].m_bounds_lim);
m_idiv_terms.shrink(m_scopes[old_size].m_idiv_lim);
m_asserted_atoms.shrink(m_scopes[old_size].m_asserted_atoms_lim);
m_asserted_qhead = m_scopes[old_size].m_asserted_qhead;
m_scopes.resize(old_size);
@ -1480,7 +1480,7 @@ public:
}
void random_update() {
if (m_nla)
if (m_nla && m_nla->need_check())
return;
m_tmp_var_set.clear();
m_tmp_var_set.resize(th.get_num_vars());
@ -1799,96 +1799,13 @@ public:
*/
bool check_idiv_bounds() {
if (m_idiv_terms.empty()) {
if (!m_nla)
return true;
}
bool all_divs_valid = true;
unsigned count = 0;
unsigned offset = ctx().get_random_value();
for (unsigned j = 0; j < m_idiv_terms.size(); ++j) {
unsigned i = (offset + j) % m_idiv_terms.size();
expr* n = m_idiv_terms[i];
if (false && !ctx().is_relevant(n))
continue;
expr* p = nullptr, *q = nullptr;
VERIFY(a.is_idiv(n, p, q));
theory_var v = internalize_def(to_app(n));
theory_var v1 = internalize_def(to_app(p));
if (!is_registered_var(v1))
continue;
lp::impq r1 = get_ivalue(v1);
rational r2;
if (!r1.x.is_int() || r1.x.is_neg() || !r1.y.is_zero()) {
// TBD
// r1 = 223/4, r2 = 2, r = 219/8
// take ceil(r1), floor(r1), ceil(r2), floor(r2), for floor(r2) > 0
// then
// p/q <= ceil(r1)/floor(r2) => n <= div(ceil(r1), floor(r2))
// p/q >= floor(r1)/ceil(r2) => n >= div(floor(r1), ceil(r2))
continue;
}
if (a.is_numeral(q, r2) && r2.is_pos()) {
if (!a.is_bounded(n)) {
TRACE("arith", tout << "unbounded " << expr_ref(n, m) << "\n";);
continue;
}
if (!is_registered_var(v))
continue;
lp::impq val_v = get_ivalue(v);
if (val_v.y.is_zero() && val_v.x == div(r1.x, r2))
continue;
TRACE("arith", tout << get_value(v) << " != " << r1 << " div " << r2 << "\n";);
rational div_r = div(r1.x, r2);
// p <= q * div(r1, q) + q - 1 => div(p, q) <= div(r1, r2)
// p >= q * div(r1, q) => div(r1, q) <= div(p, q)
rational mul(1);
rational hi = r2 * div_r + r2 - 1;
rational lo = r2 * div_r;
// used to normalize inequalities so they
// don't appear as 8*x >= 15, but x >= 2
expr *n1 = nullptr, *n2 = nullptr;
if (a.is_mul(p, n1, n2) && a.is_extended_numeral(n1, mul) && mul.is_pos()) {
p = n2;
hi = floor(hi/mul);
lo = ceil(lo/mul);
}
literal p_le_r1 = mk_literal(a.mk_le(p, a.mk_numeral(hi, true)));
literal p_ge_r1 = mk_literal(a.mk_ge(p, a.mk_numeral(lo, true)));
literal n_le_div = mk_literal(a.mk_le(n, a.mk_numeral(div_r, true)));
literal n_ge_div = mk_literal(a.mk_ge(n, a.mk_numeral(div_r, true)));
{
scoped_trace_stream _sts(th, ~p_le_r1, n_le_div);
mk_axiom(~p_le_r1, n_le_div);
}
{
scoped_trace_stream _sts(th, ~p_ge_r1, n_ge_div);
mk_axiom(~p_ge_r1, n_ge_div);
}
all_divs_valid = false;
++count;
TRACE("arith",
tout << r1 << " div " << r2 << "\n";
literal_vector lits;
lits.push_back(~p_le_r1);
lits.push_back(n_le_div);
ctx().display_literals_verbose(tout, lits) << "\n\n";
lits[0] = ~p_ge_r1;
lits[1] = n_ge_div;
ctx().display_literals_verbose(tout, lits) << "\n";);
continue;
}
}
return all_divs_valid;
m_nla_lemma_vector.reset();
m_nla->check_bounded_divisions(m_nla_lemma_vector);
for (auto & lemma : m_nla_lemma_vector)
false_case_of_check_nla(lemma);
return m_nla_lemma_vector.empty();
}
expr_ref var2expr(lpvar v) {
@ -2105,9 +2022,8 @@ public:
lbool r = m_nla->check(m_nla_lemma_vector);
switch (r) {
case l_false: {
for (const nla::lemma & l : m_nla_lemma_vector) {
false_case_of_check_nla(l);
}
for (const nla::lemma & l : m_nla_lemma_vector)
false_case_of_check_nla(l);
break;
}
case l_true:
@ -2126,11 +2042,11 @@ public:
TRACE("arith", tout << "canceled\n";);
return l_undef;
}
if (!m_nla) {
TRACE("arith", tout << "no nla\n";);
CTRACE("arith",!m_nla, tout << "no nla\n";);
if (!m_nla)
return l_true;
if (!m_nla->need_check())
return l_true;
}
if (!m_nla->need_check()) return l_true;
return check_nla_continue();
}