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use heap to track infeasible columns. (#6771)

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* use heap to track infeasible columns

* fix the formatting

Signed-off-by: Lev Nachmanson <levnach@hotmail.com>

---------

Signed-off-by: Lev Nachmanson <levnach@hotmail.com>
This commit is contained in:
Lev Nachmanson 2023-06-19 13:50:14 -07:00 • committed by GitHub
parent 4d44e60c33
commit 32ec02778e
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GPG key ID: 4AEE18F83AFDEB23
12 changed files with 116 additions and 102 deletions
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30
src/math/lp/lar_solver.cpp
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@ -244,6 +244,14 @@ namespace lp {
set.erase(j);
}
void lar_solver::clean_popped_elements_for_heap(unsigned n, lpvar_heap& heap) {
vector<int> to_remove;
for (unsigned j : heap)
if (j >= n)
to_remove.push_back(j);
for (unsigned j : to_remove)
heap.erase(j);
}
void lar_solver::pop(unsigned k) {
@ -271,7 +279,7 @@ namespace lp {
unsigned m = A_r().row_count();
clean_popped_elements(m, m_rows_with_changed_bounds);
clean_inf_set_of_r_solver_after_pop();
clean_inf_heap_of_r_solver_after_pop();
lp_assert(
m_settings.simplex_strategy() == simplex_strategy_enum::undecided ||
m_mpq_lar_core_solver.m_r_solver.reduced_costs_are_correct_tableau());
@ -328,7 +336,7 @@ namespace lp {
void lar_solver::set_costs_to_zero(const lar_term& term) {
auto& rslv = m_mpq_lar_core_solver.m_r_solver;
auto& jset = m_mpq_lar_core_solver.m_r_solver.inf_set(); // hijack this set that should be empty right now
auto& jset = m_mpq_lar_core_solver.m_r_solver.inf_heap(); // hijack this set that should be empty right now
lp_assert(jset.empty());
for (lar_term::ival p : term) {
@ -674,9 +682,9 @@ namespace lp {
void lar_solver::update_x_and_inf_costs_for_column_with_changed_bounds(unsigned j) {
if (m_mpq_lar_core_solver.m_r_heading[j] >= 0) {
if (costs_are_used()) {
bool was_infeas = m_mpq_lar_core_solver.m_r_solver.inf_set_contains(j);
bool was_infeas = m_mpq_lar_core_solver.m_r_solver.inf_heap_contains(j);
m_mpq_lar_core_solver.m_r_solver.track_column_feasibility(j);
if (was_infeas != m_mpq_lar_core_solver.m_r_solver.inf_set_contains(j))
if (was_infeas != m_mpq_lar_core_solver.m_r_solver.inf_heap_contains(j))
m_basic_columns_with_changed_cost.insert(j);
}
else {
@ -1293,12 +1301,12 @@ namespace lp {
lp_assert(m_mpq_lar_core_solver.m_r_solver.basis_heading_is_correct());
}
void lar_solver::clean_inf_set_of_r_solver_after_pop() {
void lar_solver::clean_inf_heap_of_r_solver_after_pop() {
vector<unsigned> became_feas;
clean_popped_elements(A_r().column_count(), m_mpq_lar_core_solver.m_r_solver.inf_set());
clean_popped_elements_for_heap(A_r().column_count(), m_mpq_lar_core_solver.m_r_solver.inf_heap());
std::unordered_set<unsigned> basic_columns_with_changed_cost;
m_inf_index_copy.reset();
for (auto j : m_mpq_lar_core_solver.m_r_solver.inf_set())
for (auto j : m_mpq_lar_core_solver.m_r_solver.inf_heap())
m_inf_index_copy.push_back(j);
for (auto j : m_inf_index_copy) {
if (m_mpq_lar_core_solver.m_r_heading[j] >= 0) {
@ -1316,16 +1324,16 @@ namespace lp {
lp_assert(m_mpq_lar_core_solver.m_r_solver.m_basis_heading[j] < 0);
m_mpq_lar_core_solver.m_r_solver.m_d[j] -= m_mpq_lar_core_solver.m_r_solver.m_costs[j];
m_mpq_lar_core_solver.m_r_solver.m_costs[j] = zero_of_type<mpq>();
m_mpq_lar_core_solver.m_r_solver.remove_column_from_inf_set(j);
m_mpq_lar_core_solver.m_r_solver.remove_column_from_inf_heap(j);
}
became_feas.clear();
for (unsigned j : m_mpq_lar_core_solver.m_r_solver.inf_set()) {
for (unsigned j : m_mpq_lar_core_solver.m_r_solver.inf_heap()) {
lp_assert(m_mpq_lar_core_solver.m_r_heading[j] >= 0);
if (m_mpq_lar_core_solver.m_r_solver.column_is_feasible(j))
became_feas.push_back(j);
}
for (unsigned j : became_feas)
m_mpq_lar_core_solver.m_r_solver.remove_column_from_inf_set(j);
m_mpq_lar_core_solver.m_r_solver.remove_column_from_inf_heap(j);
}
@ -1504,7 +1512,7 @@ namespace lp {
m_mpq_lar_core_solver.m_r_x.resize(j + 1);
m_mpq_lar_core_solver.m_r_lower_bounds.increase_size_by_one();
m_mpq_lar_core_solver.m_r_upper_bounds.increase_size_by_one();
m_mpq_lar_core_solver.m_r_solver.inf_set_increase_size_by_one();
m_mpq_lar_core_solver.m_r_solver.inf_heap_increase_size_by_one();
m_mpq_lar_core_solver.m_r_solver.m_costs.resize(j + 1);
m_mpq_lar_core_solver.m_r_solver.m_d.resize(j + 1);
lp_assert(m_mpq_lar_core_solver.m_r_heading.size() == j); // as A().column_count() on the entry to the method