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working on #5614

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there are some different sources for the performance regression illustrated by the example. The mitigations will be enabled separately:
- m_bv_to_propagate is too expensive
- lp_bound_propagator misses equalities in two different ways:
   - it resets row checks after backtracking even though they could still propagate
   - it misses equalities for fixed rows when the fixed constant value does not correspond to a fixed variable.

FYI @levnach
This commit is contained in:
Nikolaj Bjorner 2021-11-02 14:55:28 -07:00
parent a94e2e62af
commit 87d4ce2659
13 changed files with 422 additions and 385 deletions
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51
src/math/lp/lar_solver.cpp
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@ -16,6 +16,9 @@ namespace lp {
lp_settings const& lar_solver::settings() const { return m_settings; }
statistics& lar_solver::stats() { return m_settings.stats(); }
void lar_solver::updt_params(params_ref const& _p) {
smt_params_helper p(_p);
set_track_pivoted_rows(p.arith_bprop_on_pivoted_rows());
@ -23,17 +26,9 @@ namespace lp {
m_settings.updt_params(_p);
}
void clear() {
lp_assert(false); // not implemented
}
lar_solver::lar_solver() :
m_status(lp_status::UNKNOWN),
m_crossed_bounds_column(-1),
m_mpq_lar_core_solver(m_settings, *this),
m_int_solver(nullptr),
m_need_register_terms(false),
m_var_register(false),
m_term_register(true),
m_constraints(*this) {}
@ -197,11 +192,11 @@ namespace lp {
void lar_solver::set_status(lp_status s) { m_status = s; }
lp_status lar_solver::find_feasible_solution() {
m_settings.stats().m_make_feasible++;
if (A_r().column_count() > m_settings.stats().m_max_cols)
m_settings.stats().m_max_cols = A_r().column_count();
if (A_r().row_count() > m_settings.stats().m_max_rows)
m_settings.stats().m_max_rows = A_r().row_count();
stats().m_make_feasible++;
if (A_r().column_count() > stats().m_max_cols)
stats().m_max_cols = A_r().column_count();
if (A_r().row_count() > stats().m_max_rows)
stats().m_max_rows = A_r().row_count();
if (strategy_is_undecided())
decide_on_strategy_and_adjust_initial_state();
@ -248,7 +243,7 @@ namespace lp {
m_constraints.push();
m_usage_in_terms.push();
}
void lar_solver::clean_popped_elements(unsigned n, u_set& set) {
vector<int> to_remove;
for (unsigned j : set)
@ -269,9 +264,8 @@ namespace lp {
m_crossed_bounds_column.pop(k);
unsigned n = m_columns_to_ul_pairs.peek_size(k);
m_var_register.shrink(n);
if (m_settings.use_tableau()) {
if (m_settings.use_tableau())
pop_tableau();
}
lp_assert(A_r().column_count() == n);
TRACE("lar_solver_details",
for (unsigned j = 0; j < n; j++) {
@ -285,6 +279,10 @@ namespace lp {
clean_popped_elements(n, m_columns_with_changed_bounds);
clean_popped_elements(n, m_incorrect_columns);
for (auto rid : m_row_bounds_to_replay)
insert_row_with_changed_bounds(rid);
m_row_bounds_to_replay.reset();
unsigned m = A_r().row_count();
clean_popped_elements(m, m_rows_with_changed_bounds);
clean_inf_set_of_r_solver_after_pop();
@ -633,6 +631,9 @@ namespace lp {
left_side.push_back(std::make_pair(p.second, p.first));
}
void lar_solver::insert_row_with_changed_bounds(unsigned rid) {
m_rows_with_changed_bounds.insert(rid);
}
void lar_solver::detect_rows_of_bound_change_column_for_nbasic_column(unsigned j) {
if (A_r().row_count() != m_column_buffer.data_size())
@ -643,14 +644,14 @@ namespace lp {
m_mpq_lar_core_solver.m_r_solver.solve_Bd(j, m_column_buffer);
for (unsigned i : m_column_buffer.m_index)
m_rows_with_changed_bounds.insert(i);
insert_row_with_changed_bounds(i);
}
void lar_solver::detect_rows_of_bound_change_column_for_nbasic_column_tableau(unsigned j) {
for (auto& rc : m_mpq_lar_core_solver.m_r_A.m_columns[j])
m_rows_with_changed_bounds.insert(rc.var());
insert_row_with_changed_bounds(rc.var());
}
bool lar_solver::use_tableau() const { return m_settings.use_tableau(); }
@ -743,7 +744,7 @@ namespace lp {
void lar_solver::detect_rows_with_changed_bounds_for_column(unsigned j) {
if (m_mpq_lar_core_solver.m_r_heading[j] >= 0) {
m_rows_with_changed_bounds.insert(m_mpq_lar_core_solver.m_r_heading[j]);
insert_row_with_changed_bounds(m_mpq_lar_core_solver.m_r_heading[j]);
return;
}
@ -793,7 +794,7 @@ namespace lp {
update_x_and_inf_costs_for_columns_with_changed_bounds();
m_mpq_lar_core_solver.solve();
set_status(m_mpq_lar_core_solver.m_r_solver.get_status());
lp_assert(((m_settings.stats().m_make_feasible% 100) != 0) || m_status != lp_status::OPTIMAL || all_constraints_hold());
lp_assert(((stats().m_make_feasible% 100) != 0) || m_status != lp_status::OPTIMAL || all_constraints_hold());
}
@ -974,9 +975,7 @@ namespace lp {
bool lar_solver::the_left_sides_sum_to_zero(const vector<std::pair<mpq, unsigned>>& evidence) const {
std::unordered_map<var_index, mpq> coeff_map;
for (auto& it : evidence) {
mpq coeff = it.first;
constraint_index con_ind = it.second;
for (auto const & [coeff, con_ind] : evidence) {
lp_assert(m_constraints.valid_index(con_ind));
register_in_map(coeff_map, m_constraints[con_ind], coeff);
}
@ -1337,7 +1336,7 @@ namespace lp {
void lar_solver::mark_rows_for_bound_prop(lpvar j) {
auto& column = A_r().m_columns[j];
for (auto const& r : column)
m_rows_with_changed_bounds.insert(r.var());
insert_row_with_changed_bounds(r.var());
}
@ -1659,7 +1658,7 @@ namespace lp {
m_mpq_lar_core_solver.m_r_heading.push_back(m_mpq_lar_core_solver.m_r_basis.size());
m_mpq_lar_core_solver.m_r_basis.push_back(j);
if (m_settings.bound_propagation())
m_rows_with_changed_bounds.insert(A_r().row_count() - 1);
insert_row_with_changed_bounds(A_r().row_count() - 1);
}
else {
m_mpq_lar_core_solver.m_r_heading.push_back(-static_cast<int>(m_mpq_lar_core_solver.m_r_nbasis.size()) - 1);
@ -1755,7 +1754,7 @@ namespace lp {
if (use_tableau() && !coeffs.empty()) {
add_row_from_term_no_constraint(m_terms.back(), ret);
if (m_settings.bound_propagation())
m_rows_with_changed_bounds.insert(A_r().row_count() - 1);
insert_row_with_changed_bounds(A_r().row_count() - 1);
}
lp_assert(m_var_register.size() == A_r().column_count());
if (m_need_register_terms) {