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fix term columns after rounding in cube()

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Signed-off-by: Lev Nachmanson <levnach@hotmail.com>
This commit is contained in:
Lev Nachmanson 2020-01-30 11:38:38 -08:00
parent 41a4dcf90c
commit 35aa98436f
4 changed files with 27 additions and 59 deletions
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77
src/math/lp/lar_solver.cpp
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@ -284,7 +284,6 @@ void lar_solver::set_status(lp_status s) { m_status = s; }
lp_status lar_solver::find_feasible_solution() {
m_settings.stats().m_make_feasible++;
restore_rounded_columns();
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)
@ -359,7 +358,6 @@ void lar_solver::shrink_inf_set_after_pop(unsigned n, int_set & set) {
void lar_solver::pop(unsigned k) {
TRACE("lar_solver", tout << "k = " << k << std::endl;);
restore_rounded_columns(); // if it is not done now, the basis changes and restore_rounded_columns would now work
m_infeasible_column.pop(k);
unsigned n = m_columns_to_ul_pairs.peek_size(k);
m_var_register.shrink(n);
@ -402,7 +400,6 @@ void lar_solver::pop(unsigned k) {
m_settings.simplex_strategy() = m_simplex_strategy;
lp_assert(sizes_are_correct());
lp_assert((!m_settings.use_tableau()) || m_mpq_lar_core_solver.m_r_solver.reduced_costs_are_correct_tableau());
lp_assert(m_cube_rounded_columns.size() != 0 || ax_is_correct());
set_status(lp_status::UNKNOWN);
}
@ -414,17 +411,6 @@ vector<constraint_index> lar_solver::get_all_constraint_indices() const {
return ret;
}
void lar_solver::restore_rounded_columns() {
for (unsigned j : m_incorrect_columns.m_index) {
SASSERT(is_base(j));
unsigned i = row_of_basic_column(j);
m_mpq_lar_core_solver.m_r_solver.update_x_and_call_tracker(j,
get_basic_var_value_from_row(i));
}
m_incorrect_columns.clear();
SASSERT(ax_is_correct());
}
bool lar_solver::maximize_term_on_tableau(const lar_term & term,
impq &term_max) {
if (settings().simplex_strategy() == simplex_strategy_enum::undecided)
@ -866,45 +852,8 @@ void lar_solver::update_x_and_inf_costs_for_columns_with_changed_bounds_tableau(
}
}
void lar_solver::fix_Ax_b_on_rounded_row(unsigned i) {
if (A_r().m_rows.size() <= i)
return;
unsigned bj = m_mpq_lar_core_solver.m_r_basis[i];
auto v = zero_of_type<impq>();
for (const auto & c : A_r().m_rows[i]) {
if (c.var() != bj)
v -= c.coeff() * m_mpq_lar_core_solver.m_r_x[c.var()];
}
m_mpq_lar_core_solver.m_r_solver.update_x_with_feasibility_tracking(bj, v);
}
void lar_solver::collect_rounded_rows_to_fix() {
lp_assert(m_cube_rounded_rows.size() == 0);
for (unsigned j : m_cube_rounded_columns) {
if (j >= A_r().m_columns.size())
continue;
int j_raw = m_mpq_lar_core_solver.m_r_solver.m_basis_heading[j];
if (j_raw >= 0) {
m_cube_rounded_rows.insert(j_raw);
} else {
for (const auto & c : A_r().m_columns[j]) {
m_cube_rounded_rows.insert(c.var());
}
}
}
}
void lar_solver::fix_Ax_b_on_rounded_rows() {
collect_rounded_rows_to_fix();
for (unsigned i : m_cube_rounded_rows) {
fix_Ax_b_on_rounded_row(i);
}
m_cube_rounded_rows.clear();
m_cube_rounded_columns.clear();
lp_assert(ax_is_correct());
}
void lar_solver::solve_with_core_solver() {
if (m_cube_rounded_columns.size() != 0)
fix_Ax_b_on_rounded_rows();
if (!use_tableau())
add_last_rows_to_lu(m_mpq_lar_core_solver.m_r_solver);
if (m_mpq_lar_core_solver.need_to_presolve_with_double_solver()) {
@ -2342,6 +2291,32 @@ void lar_solver::round_to_integer_solution() {
m_incorrect_columns.insert(j);
TRACE("cube", tout << "new val = " << v << "\n";);
}
if (m_incorrect_columns.size()) {
fix_terms_with_rounded_columns();
m_incorrect_columns.clear();
}
}
void lar_solver::fix_terms_with_rounded_columns() {
for (unsigned i = 0; i < m_terms.size(); i++) {
unsigned ti = i + terms_start_index();
if (!term_is_used_as_row(ti))
continue;
bool need_to_fix = false;
const lar_term & t = *m_terms[i];
for (const auto & p : t) {
if (m_incorrect_columns.contains(p.var())) {
need_to_fix = true;
break;
}
}
if (need_to_fix) {
lpvar j = external_to_local(ti);
impq v = t.apply(m_mpq_lar_core_solver.m_r_x);
m_mpq_lar_core_solver.m_r_solver.update_x_and_call_tracker(j, v);
}
}
SASSERT(ax_is_correct());
}
// return true if all y coords are zeroes
bool lar_solver::sum_first_coords(const lar_term& t, mpq & val) const {