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handle sat with tightening

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This commit is contained in:
Lev Nachmanson 2024-09-23 15:59:36 -07:00 committed by Lev Nachmanson
parent b1be8c0957
commit 193116bf84
2 changed files with 41 additions and 15 deletions
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54
src/math/lp/dioph_eq.cpp
View file

@ -117,7 +117,9 @@ namespace lp {
*/ */
struct eprime_pair { struct eprime_pair {
term_o m_e; term_o m_e;
u_dependency *m_l; // this term keeps the history of m_e : originally m_l is i, the index of row m_e was constructed from // we keep the dependency of the equation in m_l
// a more expensive alternative is to keep the history term of m_e : originally m_l is i, the index of row m_e was constructed from
u_dependency *m_l;
}; };
vector<eprime_pair> m_eprime; vector<eprime_pair> m_eprime;
@ -158,6 +160,7 @@ namespace lp {
void init() { void init() {
unsigned n_of_rows = lra.A_r().row_count(); unsigned n_of_rows = lra.A_r().row_count();
unsigned fn = 0; unsigned fn = 0;
m_conflict_index = -1;
auto all_vars_are_int = [this](const auto& row) { auto all_vars_are_int = [this](const auto& row) {
for (const auto& p : row) { for (const auto& p : row) {
@ -278,7 +281,11 @@ namespace lp {
if (is_one) { if (is_one) {
for (const auto& p: e.m_e) { for (const auto& p: e.m_e) {
if (p.j() == k) continue; if (p.j() == k) continue;
t.add_monomial(-p.coeff(), p.j()); unsigned j = p.j();
if (is_fresh_var(p.j())) {
j = lra.add_var(p.j(), true);
}
t.add_monomial(-p.coeff(), j);
if (m_k2s.contains(p.j())) if (m_k2s.contains(p.j()))
q.push(p.j()); q.push(p.j());
} }
@ -293,19 +300,21 @@ namespace lp {
t.c() += e.m_e.c(); t.c() += e.m_e.c();
} }
} }
void process_q_with_S(std::queue<unsigned> &q, term_o& t, const lar_base_constraint& c) { void process_q_with_S(std::queue<unsigned> &q, term_o& t, const lar_base_constraint& c, u_dependency* &dep) {
while (!q.empty()) { while (!q.empty()) {
unsigned k = q.front(); unsigned k = q.front();
TRACE("dioph_eq", tout << "k:" << k << std::endl;);
q.pop(); q.pop();
const eprime_pair& e = m_eprime[m_k2s[k]]; const eprime_pair& e = m_eprime[m_k2s[k]];
TRACE("dioph_eq", tout << "k:" << k << " in: "; print_eprime_entry(m_k2s[k], tout) << std::endl;); TRACE("dioph_eq", tout << "k:" << k << " in: "; print_eprime_entry(m_k2s[k], tout) << std::endl;);
subs_k(e, k, t, q); subs_k(e, k, t, q);
dep = lra.mk_join(dep, e.m_l);
} }
TRACE("dioph_eq", tout << "substituted t:"; print_term_o(t, tout) << std::endl;); TRACE("dioph_eq", tout << "substituted t:"; print_term_o(t, tout) << std::endl;);
} }
void tighten_with_S(const lar_base_constraint& c) { void tighten_constraint_with_S(constraint_index ci) {
const lar_base_constraint& c = lra.constraints()[ci];
u_dependency * dep = lra.dep_manager().mk_leaf(ci);
TRACE("dioph_eq", tout << "constraint:"; lra.constraints().display(tout, c) << std::endl;); TRACE("dioph_eq", tout << "constraint:"; lra.constraints().display(tout, c) << std::endl;);
SASSERT(c.is_active()); SASSERT(c.is_active());
term_o t; term_o t;
@ -317,13 +326,14 @@ namespace lp {
if (q.empty()) return; if (q.empty()) return;
init_term_from_constraint(t, c); init_term_from_constraint(t, c);
TRACE("dioph_eq", tout << "t:"; print_term_o(t, tout) << std::endl;); TRACE("dioph_eq", tout << "t:"; print_term_o(t, tout) << std::endl;);
process_q_with_S(q, t, c); process_q_with_S(q, t, c, dep);
TRACE("dioph_eq", tout << "tighten:"; print_term_o(t, tout) << std::endl;); TRACE("dioph_eq", tout << "tighten:"; print_term_o(t, tout) << std::endl;);
mpq g = gcd_of_coeffs(t); mpq g = gcd_of_coeffs(t);
if (g.is_one()) return; if (g.is_one()) return;
mpq new_c = t.c() / g; mpq new_c = t.c() / g;
if (new_c.is_int()) return; if (new_c.is_int()) return;
std::cout << "."; return; TRACE("dioph_eq", tout << "tighten:"; print_term_o(t, tout) << std::endl;
tout << "g:"<< g << std::endl;);
if (c.kind() == lconstraint_kind::EQ) { if (c.kind() == lconstraint_kind::EQ) {
TRACE("dioph_eq", tout << "conflict:" <<std::endl;); TRACE("dioph_eq", tout << "conflict:" <<std::endl;);
NOT_IMPLEMENTED_YET(); NOT_IMPLEMENTED_YET();
@ -338,16 +348,27 @@ namespace lp {
} }
t.c() = floor(new_c); t.c() = floor(new_c);
} }
TRACE("dioph_eq", tout << "tighten/g:"; print_term_o(t, tout) << std::endl;);
NOT_IMPLEMENTED_YET(); TRACE("dioph_eq", tout << "tighten/g:"; print_term_o(t, tout) << " " << lconstraint_kind_string(c.kind()) << std::endl;);
lp::lpvar j = lra.add_term(t.coeffs_as_vector(), UINT_MAX);
lra.update_column_type_and_bound(j, c.kind(), -t.c(), dep);
} }
lia_move tighten_with_S() { lia_move tighten_with_S() {
for (const auto& c: lra.constraints().active()) { std::vector<constraint_index> active_constraints_idx;
tighten_with_S(c); for (constraint_index ci: lra.constraints().indices()) {
active_constraints_idx.push_back(ci);
} }
return lia_move::undef;
for (constraint_index ci: active_constraints_idx) {
tighten_constraint_with_S(ci);
}
auto st = lra.find_feasible_solution();
if (st != lp::lp_status::FEASIBLE && st != lp::lp_status::OPTIMAL) {
return lia_move::conflict;
}
return lia_move::sat;
} }
lia_move check() { lia_move check() {
@ -358,7 +379,6 @@ namespace lp {
rewrite_eqs(); rewrite_eqs();
} }
TRACE("dioph_eq", print_S(tout);); TRACE("dioph_eq", print_S(tout););
return lia_move::sat;
return tighten_with_S(); return tighten_with_S();
} }
std::list<unsigned>::iterator pick_eh() { std::list<unsigned>::iterator pick_eh() {
@ -514,7 +534,12 @@ namespace lp {
} }
} }
void explain(lp::explanation& ex) { void explain(explanation& ex) {
if (m_conflict_index == -1) {
SASSERT(!(lra.get_status() == lp_status::FEASIBLE || lra.get_status() == lp_status::OPTIMAL));
lra.get_infeasibility_explanation(ex);
return;
}
SASSERT(ex.empty()); SASSERT(ex.empty());
TRACE("dioph_eq", tout << "conflict:"; print_eprime_entry(m_conflict_index, tout) << std::endl;); TRACE("dioph_eq", tout << "conflict:"; print_eprime_entry(m_conflict_index, tout) << std::endl;);
auto & ep = m_eprime[m_conflict_index]; auto & ep = m_eprime[m_conflict_index];
@ -532,6 +557,7 @@ namespace lp {
} }
TRACE("dioph_eq", lra.print_expl(tout, ex);); TRACE("dioph_eq", lra.print_expl(tout, ex););
} }
unsigned fresh_index(unsigned j) const {return UINT_MAX - j;} unsigned fresh_index(unsigned j) const {return UINT_MAX - j;}
void remove_fresh_variables(term_o& t) { void remove_fresh_variables(term_o& t) {

2
src/math/lp/lar_solver.cpp
View file

@ -1573,7 +1573,7 @@ namespace lp {
local_j = A_r().column_count(); local_j = A_r().column_count();
m_columns.push_back(column(false, nullptr)); // false - not associated with a row, nullptr for term m_columns.push_back(column(false, nullptr)); // false - not associated with a row, nullptr for term
m_trail.push(undo_add_column(*this)); m_trail.push(undo_add_column(*this));
while (m_usage_in_terms.size() <= ext_j) while (m_usage_in_terms.size() <= local_j)
m_usage_in_terms.push_back(0); m_usage_in_terms.push_back(0);
add_non_basic_var_to_core_fields(ext_j, is_int); add_non_basic_var_to_core_fields(ext_j, is_int);
lp_assert(sizes_are_correct()); lp_assert(sizes_are_correct());