mirrors/z3
3
0
Fork 0
mirror of https://github.com/Z3Prover/z3 synced 2025-04-27 02:45:51 +00:00
Code Activity

better branching with usage_in_terms()

Browse source 
Signed-off-by: Lev Nachmanson <levnach@hotmail.com>
This commit is contained in:
Lev Nachmanson 2020-04-27 12:48:30 -07:00
parent 3bbf1474f3
commit ba40a5752f
4 changed files with 28 additions and 34 deletions
Download patch file Download diff file Expand all files Collapse all files

39
src/math/lp/int_branch.cpp
View file

@ -25,13 +25,9 @@ namespace lp {
int_branch::int_branch(int_solver& lia):lia(lia), lra(lia.lra) {}
lia_move int_branch::operator()() {
int j = find_any_inf_int_column_basis_first();
return j == -1? lia_move::sat : create_branch_on_column(j);
}
int int_branch::find_any_inf_int_column_basis_first() {
lra.move_non_basic_columns_to_bounds();
int j = find_inf_int_base_column();
return j != -1 ? j : find_inf_int_nbasis_column();
return j == -1? lia_move::sat : create_branch_on_column(j);
}
lia_move int_branch::create_branch_on_column(int j) {
@ -55,22 +51,6 @@ lia_move int_branch::create_branch_on_column(int j) {
}
int int_branch::find_inf_int_nbasis_column() const {
unsigned n = 0;
int r = -1;
for (unsigned j : lra.r_nbasis()) {
SASSERT(!lia.column_is_int_inf(j) || !lia.is_fixed(j));
if (lia.column_is_int_inf(j)) {
if (n == 0) {
r = j;
n = 1;
} else if (lia.random() % (++n) == 0) {
r = j;
}
}
}
return r;
}
int int_branch::find_inf_int_base_column() {
int result = -1;
@ -80,15 +60,17 @@ int int_branch::find_inf_int_base_column() {
unsigned n = 0;
lar_core_solver & lcs = lra.m_mpq_lar_core_solver;
bool small = false;
unsigned prev_usage;
for (unsigned j : lra.r_basis()) {
SASSERT(!lia.column_is_int_inf(j) || !lia.is_fixed(j));
if (!lia.column_is_int_inf(j))
continue;
bool boxed = lia.is_boxed(j);
unsigned usage = 2 * lra.usage_in_terms(j);
if (small) {
if (!boxed)
continue;
new_range = lcs.m_r_upper_bounds()[j].x - lcs.m_r_lower_bounds()[j].x;
new_range = lcs.m_r_upper_bounds()[j].x - lcs.m_r_lower_bounds()[j].x - rational(usage);
if (new_range <= small_range_thresold) {
if (new_range < range) {
n = 1;
@ -98,16 +80,17 @@ int int_branch::find_inf_int_base_column() {
result = j;
}
}
} else if (boxed &&
(range = lcs.m_r_upper_bounds()[j].x - lcs.m_r_lower_bounds()[j].x)
<= small_range_thresold) {
} else if (boxed && (
(range = lcs.m_r_upper_bounds()[j].x - lcs.m_r_lower_bounds()[j].x - rational(usage))
<= small_range_thresold)) {
small = true;
result = j;
n = 1;
} else if (result == -1) {
} else if (result == -1 || prev_usage < usage) {
result = j;
prev_usage = usage;
n = 1;
} else if (lia.random() % (++n) == 0) {
} else if (prev_usage == usage && lia.random() % (++n) == 0) {
result = j;
}
}