mirrors/z3
3
0
Fork 0
mirror of https://github.com/Z3Prover/z3 synced 2025-04-28 19:35:50 +00:00
Code Activity

separate out int-branch

Browse source 
Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2020-02-08 15:58:06 -08:00
parent 3f1f4e0f67
commit 8b9a80e232
5 changed files with 181 additions and 117 deletions
Download patch file Download diff file Expand all files Collapse all files

108
src/math/lp/int_solver.cpp
View file

@ -10,6 +10,7 @@
#include "math/lp/monic.h"
#include "math/lp/gomory.h"
#include "math/lp/int_cube.h"
#include "math/lp/int_branch.h"
namespace lp {
@ -34,66 +35,6 @@ std::ostream& int_solver::display_inf_rows(std::ostream& out) const {
return out;
}
int int_solver::find_inf_int_base_column() {
unsigned inf_int_count = 0;
int j = find_inf_int_boxed_base_column_with_smallest_range(inf_int_count);
if (j != -1) {
return j;
}
if (inf_int_count == 0)
return -1;
unsigned k = random() % inf_int_count;
return get_kth_inf_int(k);
}
int int_solver::get_kth_inf_int(unsigned k) const {
for (unsigned j : lra.r_basis())
if (column_is_int_inf(j) && k-- == 0)
return j;
lp_assert(false);
return -1;
}
int int_solver::find_inf_int_nbasis_column() const {
for (unsigned j : lra.r_nbasis())
if (!column_is_int_inf(j)) {
return j;
}
return -1;
}
int int_solver::find_inf_int_boxed_base_column_with_smallest_range(unsigned & inf_int_count) {
inf_int_count = 0;
int result = -1;
mpq range;
mpq new_range;
mpq small_range_thresold(1024);
unsigned n = 0;
lar_core_solver & lcs = lra.m_mpq_lar_core_solver;
for (unsigned j : lra.r_basis()) {
if (!column_is_int_inf(j))
continue;
inf_int_count++;
if (!is_boxed(j))
continue;
lp_assert(!is_fixed(j));
new_range = lcs.m_r_upper_bounds()[j].x - lcs.m_r_lower_bounds()[j].x;
if (new_range > small_range_thresold)
continue;
if (result == -1 || new_range < range) {
result = j;
range = new_range;
n = 1;
}
else if (new_range == range && settings().random_next() % (++n) == 0) {
lp_assert(n > 1);
result = j;
}
}
return result;
}
bool int_solver::current_solution_is_inf_on_cut() const {
const auto & x = lra.m_mpq_lar_core_solver.m_r_x;
impq v = m_t.apply(x);
@ -338,14 +279,10 @@ lia_move int_solver::check(lp::explanation * e) {
}
lia_move int_solver::branch_or_sat() {
int j = find_any_inf_int_column_basis_first();
return j == -1? lia_move::sat : create_branch_on_column(j);
int_branch b(*this);
return b();
}
int int_solver::find_any_inf_int_column_basis_first() {
int j = find_inf_int_base_column();
return j != -1 ? j : find_inf_int_nbasis_column();
}
void int_solver::set_value_for_nbasic_column_ignore_old_values(unsigned j, const impq & new_val) {
lp_assert(!is_base(j));
@ -881,45 +818,6 @@ bool int_solver::non_basic_columns_are_at_bounds() const {
const impq& int_solver::lower_bound(unsigned j) const {
return lra.column_lower_bound(j);
}
lia_move int_solver::create_branch_on_column(int j) {
TRACE("check_main_int", tout << "branching" << std::endl;);
lp_assert(m_t.is_empty());
lp_assert(j != -1);
m_t.add_monomial(mpq(1), lra.adjust_column_index_to_term_index(j));
if (is_free(j)) {
m_upper = random() % 2;
m_k = mpq(0);
}
else {
m_upper = left_branch_is_more_narrow_than_right(j);
m_k = m_upper? floor(get_value(j)) : ceil(get_value(j));
}
TRACE("int_solver",
display_column(tout << "branching v" << j << " = " << get_value(j) << "\n", j);
tout << "k = " << m_k << std::endl;);
return lia_move::branch;
}
bool int_solver::left_branch_is_more_narrow_than_right(unsigned j) {
switch (lra.m_mpq_lar_core_solver.m_r_solver.m_column_types[j] ) {
case column_type::fixed:
return false;
case column_type::boxed:
{
auto k = floor(get_value(j));
return k - lower_bound(j).x < upper_bound(j).x - (k + mpq(1));
}
case column_type::lower_bound:
return true;
case column_type::upper_bound:
return false;
default:
return false;
}
}
}