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use the simple version of move_non_basic_column_to_bounds

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This commit is contained in:
Lev Nachmanson 2023-10-05 20:57:54 -07:00
parent bf3817ef7c
commit f847d039bc
5 changed files with 27 additions and 33 deletions
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2
src/math/lp/gomory.cpp
View file

@ -417,7 +417,7 @@ int gomory::find_basic_var() {
}
lia_move gomory::operator()() {
lra.move_non_basic_columns_to_bounds(true);
lra.move_non_basic_columns_to_bounds();
int j = find_basic_var();
if (j == -1)
return lia_move::undef;

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

@ -24,7 +24,7 @@ namespace lp {
int_branch::int_branch(int_solver& lia):lia(lia), lra(lia.lra) {}
lia_move int_branch::operator()() {
lra.move_non_basic_columns_to_bounds(true);
lra.move_non_basic_columns_to_bounds();
int j = find_inf_int_base_column();
return j == -1? lia_move::sat : create_branch_on_column(j);
}

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

@ -43,7 +43,7 @@ namespace lp {
if (st != lp_status::FEASIBLE && st != lp_status::OPTIMAL) {
TRACE("cube", tout << "cannot find a feasible solution";);
lra.pop();
lra.move_non_basic_columns_to_bounds(false);
lra.move_non_basic_columns_to_bounds();
// it can happen that we found an integer solution here
return !lra.r_basis_has_inf_int()? lia_move::sat: lia_move::undef;
}

50
src/math/lp/lar_solver.cpp
View file

@ -402,7 +402,7 @@ namespace lp {
void lar_solver::prepare_costs_for_r_solver(const lar_term& term) {
TRACE("lar_solver", print_term(term, tout << "prepare: ") << "\n";);
move_non_basic_columns_to_bounds(false);
move_non_basic_columns_to_bounds();
auto& rslv = m_mpq_lar_core_solver.m_r_solver;
lp_assert(costs_are_zeros_for_r_solver());
lp_assert(reduced_costs_are_zeroes_for_r_solver());
@ -419,11 +419,11 @@ namespace lp {
lp_assert(rslv.reduced_costs_are_correct_tableau());
}
void lar_solver::move_non_basic_columns_to_bounds(bool shift_randomly) {
void lar_solver::move_non_basic_columns_to_bounds() {
auto& lcs = m_mpq_lar_core_solver;
bool change = false;
for (unsigned j : lcs.m_r_nbasis) {
if (move_non_basic_column_to_bounds(j, shift_randomly))
if (move_non_basic_column_to_bounds(j))
change = true;
}
if (!change)
@ -434,46 +434,40 @@ namespace lp {
find_feasible_solution();
}
bool lar_solver::move_non_basic_column_to_bounds(unsigned j, bool force_change) {
bool lar_solver::move_non_basic_column_to_bounds(unsigned j) {
auto& lcs = m_mpq_lar_core_solver;
auto& val = lcs.m_r_x[j];
switch (lcs.m_column_types()[j]) {
case column_type::boxed: {
bool at_l = val == lcs.m_r_lower_bounds()[j];
bool at_u = (!at_l && (val == lcs.m_r_upper_bounds()[j]));
if (!at_l && !at_u) {
if (m_settings.random_next() % 2)
set_value_for_nbasic_column(j, lcs.m_r_lower_bounds()[j]);
else
set_value_for_nbasic_column(j, lcs.m_r_upper_bounds()[j]);
return true;
}
else if (force_change && m_settings.random_next() % 3 == 0) {
set_value_for_nbasic_column(j,
at_l ? lcs.m_r_upper_bounds()[j] : lcs.m_r_lower_bounds()[j]);
return true;
}
break;
}
case column_type::lower_bound:
const auto& l = lcs.m_r_lower_bounds()[j];
if (val == l || val == lcs.m_r_upper_bounds()[j]) return false;
set_value_for_nbasic_column(j, l);
return true;
}
case column_type::lower_bound: {
const auto& l = lcs.m_r_lower_bounds()[j];
if (val != lcs.m_r_lower_bounds()[j]) {
set_value_for_nbasic_column(j, lcs.m_r_lower_bounds()[j]);
set_value_for_nbasic_column(j, l);
return true;
}
break;
return false;
}
case column_type::fixed:
case column_type::upper_bound:
if (val != lcs.m_r_upper_bounds()[j]) {
set_value_for_nbasic_column(j, lcs.m_r_upper_bounds()[j]);
case column_type::upper_bound: {
const auto & u = lcs.m_r_upper_bounds()[j];
if (val != u) {
set_value_for_nbasic_column(j, u);
return true;
}
break;
return false;
}
case column_type::free_column:
if (column_is_int(j) && !val.is_int()) {
set_value_for_nbasic_column(j, impq(floor(val)));
return true;
}
break;
return false;
default:
SASSERT(false);
}

4
src/math/lp/lar_solver.h
View file

@ -635,8 +635,8 @@ class lar_solver : public column_namer {
return *m_terms[t.id()];
}
lp_status find_feasible_solution();
void move_non_basic_columns_to_bounds(bool);
bool move_non_basic_column_to_bounds(unsigned j, bool);
void move_non_basic_columns_to_bounds();
bool move_non_basic_column_to_bounds(unsigned j);
inline bool r_basis_has_inf_int() const {
for (unsigned j : r_basis()) {
if (column_is_int(j) && !column_value_is_int(j))