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remove unnecessery dependency when tightening a bound
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Signed-off-by: Lev Nachmanson <[email protected]>
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@levnach
levnach committed Feb 24, 2025
1 parent 8414e18 commit 3271f2f
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Showing 2 changed files with 61 additions and 50 deletions.
109 changes: 60 additions & 49 deletions src/math/lp/dioph_eq.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -250,17 +250,22 @@ namespace lp {
return out;
}

std::ostream& print_column_bounds(std::ostream& out, unsigned j) {
out << "j" << j << ":= " << lra.get_column_value(j).x << ": ";
if (lra.column_has_lower_bound(j))
out << lra.column_lower_bound(j).x << " <= ";
out << "x" << j;
if (lra.column_has_upper_bound(j))
out << " <= " << lra.column_upper_bound(j).x;
out << "\n";
return out;
}

std::ostream& print_bounds(std::ostream& out) {
out << "bounds:\n";
for (unsigned v = 0; v < m_var_register.size(); ++v) {
unsigned j = m_var_register.local_to_external(v);
out << "j" << j << ":= " << lra.get_column_value(j).x << ": ";
if (lra.column_has_lower_bound(j))
out << lra.column_lower_bound(j).x << " <= ";
out << "x" << v;
if (lra.column_has_upper_bound(j))
out << " <= " << lra.column_upper_bound(j).x;
out << "\n";
print_column_bounds(out, j);
}
return out;
}
Expand Down Expand Up @@ -1358,6 +1363,14 @@ namespace lp {
return weight;
}

bool term_has_int_inv_vars(unsigned j) const {
for (const auto & p: lra.get_term(j)) {
if (lia.column_is_int_inf(p.var()))
return true;
}
return false;
}

lia_move tighten_terms_with_S() {
// Copy changed terms to another vector for sorting
std_vector<unsigned> sorted_changed_terms;
Expand All @@ -1368,7 +1381,11 @@ namespace lp {
j >= lra.column_count() ||
!lra.column_has_term(j) ||
lra.column_is_free(j) ||
is_fixed(j) || !lia.column_is_int(j)) {
is_fixed(j) ||
!lia.column_is_int(j)
||
!term_has_int_inv_vars(j)
) {
cleanup.push_back(j);
continue;
}
Expand Down Expand Up @@ -1436,7 +1453,7 @@ namespace lp {
m_c = mpq(0);
m_lspace.clear();
SASSERT(get_extended_term_value(lar_t).is_zero());
TRACE("dioph_eq", tout << "t:";print_lar_term_L(lar_t, tout) << std::endl; tout << "value:" << get_extended_term_value(lar_t) << std::endl;);
TRACE("dio", tout << "t:";print_lar_term_L(lar_t, tout) << std::endl; tout << "value:" << get_extended_term_value(lar_t) << std::endl;);
for (const auto& p : lar_t) {
SASSERT(p.coeff().is_int());
if (is_fixed(p.j())) {
Expand All @@ -1450,7 +1467,7 @@ namespace lp {
q.push(lar_solver_to_local(p.j()));
}
}
TRACE("dioph_eq", tout << "m_espace:"; print_term_o(create_term_from_subst_space(), tout) << std::endl;
TRACE("dio", tout << "m_espace:"; print_term_o(create_term_from_subst_space(), tout) << std::endl;
tout << "m_c:" << m_c << std::endl;
tout << "get_value_of_subs_space:" << get_value_of_espace() << std::endl;);
}
Expand All @@ -1468,24 +1485,23 @@ namespace lp {
return lia_move::undef;
// q is the queue of variables that can be substituted in term_to_tighten
protected_queue q;
TRACE("dioph_eq", tout << "j:" << j << ", t: "; print_lar_term_L(term_to_tighten, tout) << std::endl;);
TRACE("dio", tout << "j:" << j << ", t: "; print_lar_term_L(term_to_tighten, tout) << std::endl;);
init_substitutions(term_to_tighten, q);
if (q.empty())
return lia_move::undef;

TRACE("dioph_eq", tout << "t:"; print_lar_term_L(term_to_tighten, tout) << std::endl;
tout << "subs_space:"; print_term_o(create_term_from_subst_space(), tout) << std::endl;
TRACE("dio", tout << "t:";
tout << "m_espace:";
print_term_o(create_term_from_subst_space(), tout) << std::endl;
tout << "m_lspace:";
print_lar_term_L(m_lspace.to_term(), tout) << std::endl;);
subs_with_S_and_fresh(q);
TRACE("dioph_eq", tout << "after subs\n"; print_term_o(create_term_from_subst_space(), tout) << std::endl; tout << "m_l_term_space:"; print_lar_term_L(m_lspace.to_term(), tout) << std::endl; tout << "open_ml:"; print_lar_term_L(open_ml(m_lspace.to_term()), tout) << std::endl; tout << "term_to_tighten + open_ml:"; print_term_o(term_to_tighten + open_ml(m_lspace.to_term()), tout) << std::endl; term_o ls = fix_vars(term_to_tighten + open_ml(m_lspace.to_term())); tout << "ls:"; print_term_o(ls, tout) << std::endl; term_o rs = term_to_lar_solver(remove_fresh_vars(create_term_from_subst_space())); tout << "rs:"; print_term_o(rs, tout) << std::endl; term_o diff = ls - rs; if (!diff.is_empty()) {
tout << "diff:"; print_term_o(diff, tout ) << std::endl; });

SASSERT(
fix_vars(term_to_tighten + open_ml(m_lspace.to_term())) ==

SASSERT(fix_vars(term_to_tighten + open_ml(m_lspace.to_term())) ==
term_to_lar_solver(remove_fresh_vars(create_term_from_subst_space())));

mpq g = gcd_of_coeffs(m_espace.m_data, true);
TRACE("dioph_eq", tout << "after process_q_with_S\nt:"; print_term_o(create_term_from_subst_space(), tout) << std::endl; tout << "g:" << g << std::endl;);
TRACE("dio", tout << "after process_q_with_S\nt:"; print_term_o(create_term_from_subst_space(), tout) << std::endl; tout << "g:" << g << std::endl;);

if (g.is_one())
return lia_move::undef;
Expand Down Expand Up @@ -1580,8 +1596,8 @@ namespace lp {
lia.offset() = floor(rs);
lia.is_upper() = true;
m_report_branch = true;
enable_trace("dioph_eq");
TRACE("dioph_eq", tout << "prepare branch, t:";
enable_trace("dio");
TRACE("dio", tout << "prepare branch, t:";
print_lar_term_L(t, tout)
<< " <= " << lia.offset()
<< std::endl;
Expand Down Expand Up @@ -1690,10 +1706,10 @@ namespace lp {
SASSERT(!g.is_zero());

if (lra.has_bound_of_type(j, b_dep, rs, is_strict, is_upper)) {
TRACE("dioph_eq", tout << "current upper bound for x" << j << ":"
TRACE("dio", tout << "current upper bound for x" << j << ":"
<< rs << std::endl;);
rs = (rs - m_c) / g;
TRACE("dioph_eq", tout << "(rs - m_c) / g:" << rs << std::endl;);
TRACE("dio", tout << "(rs - m_c) / g:" << rs << std::endl;);
if (!rs.is_int()) {
if (tighten_bound_kind(g, j, rs, is_upper, b_dep))
return lia_move::conflict;
Expand All @@ -1714,24 +1730,19 @@ namespace lp {
// <= can be replaced with >= for lower bounds, with ceil instead of
// floor
mpq bound = g * (upper ? floor(ub) : ceil(ub)) + m_c;
TRACE("dioph_eq", tout << "is upper:" << upper << std::endl;
TRACE("dio", tout << "is upper:" << upper << std::endl;
tout << "new " << (upper ? "upper" : "lower")
<< " bound:" << bound << std::endl;);

SASSERT((upper && bound < lra.get_upper_bound(j).x) ||
(!upper && bound > lra.get_lower_bound(j).x));
lconstraint_kind kind =
upper ? lconstraint_kind::LE : lconstraint_kind::GE;
lconstraint_kind kind = upper ? lconstraint_kind::LE : lconstraint_kind::GE;
u_dependency* dep = prev_dep;
dep = lra.join_deps(dep, explain_fixed_in_meta_term(m_lspace.m_data));
u_dependency* j_bound_dep = upper
? lra.get_column_upper_bound_witness(j)
: lra.get_column_lower_bound_witness(j);
u_dependency* j_bound_dep = upper ? lra.get_column_upper_bound_witness(j) : lra.get_column_lower_bound_witness(j);
dep = lra.join_deps(dep, j_bound_dep);
dep = lra.join_deps(dep, explain_fixed(lra.get_term(j)));
dep =
lra.join_deps(dep, lra.get_bound_constraint_witnesses_for_column(j));
TRACE("dioph_eq", tout << "jterm:";
TRACE("dio", tout << "jterm:";
print_lar_term_L(lra.get_term(j), tout) << "\ndep:";
print_deps(tout, dep) << std::endl;);
lra.update_column_type_and_bound(j, kind, bound, dep);
Expand Down Expand Up @@ -1799,7 +1810,7 @@ namespace lp {
lia_move ret = process_f();
if (ret != lia_move::undef)
return ret;
TRACE("dioph_eq", print_S(tout););
TRACE("dio", print_S(tout););
ret = tighten_terms_with_S();
if (ret == lia_move::conflict) {
lra.stats().m_dio_tighten_conflicts++;
Expand Down Expand Up @@ -2096,7 +2107,7 @@ namespace lp {
unsigned j = p.first;
const auto it = m_columns_to_terms.find(j);
if (it == m_columns_to_terms.end()) {
TRACE("dioph_eq", tout << "column j" << j << " is not registered" << std::endl; tout << "the column belongs to the the following terms:"; for (unsigned tj : p.second) { tout << " " << tj; } tout << std::endl;);
TRACE("dio", tout << "column j" << j << " is not registered" << std::endl; tout << "the column belongs to the the following terms:"; for (unsigned tj : p.second) { tout << " " << tj; } tout << std::endl;);

return false;
}
Expand All @@ -2112,7 +2123,7 @@ namespace lp {
unsigned j = p.first;
const auto it = c2t.find(j);
if (it == c2t.end()) {
TRACE("dioph_eq", tout << "should not be registered j " << j << std::endl;
TRACE("dio", tout << "should not be registered j " << j << std::endl;
lra.print_terms(tout););
return false;
}
Expand Down Expand Up @@ -2148,7 +2159,7 @@ namespace lp {
public:
lia_move check() {
lra.stats().m_dio_calls++;
TRACE("dioph_eq", tout << lra.stats().m_dio_calls << std::endl;);
TRACE("dio", tout << lra.stats().m_dio_calls << std::endl;);
init();
lia_move ret = process_f_and_tighten_terms();
if (ret == lia_move::branch || ret == lia_move::conflict)
Expand Down Expand Up @@ -2210,7 +2221,7 @@ namespace lp {
t.add_monomial(-k_sign * p.coeff(), p.j());
}
t.c() = -k_sign * eh.c();
TRACE("dioph_eq", tout << "subst_term:";
TRACE("dio", tout << "subst_term:";
print_term_o(t, tout) << std::endl;);
return t;
}
Expand All @@ -2231,7 +2242,7 @@ namespace lp {
SASSERT(belongs_to_s(ei));
const auto& e = m_sum_of_fixed[ei];
SASSERT(j_sign_is_correct(ei, j, j_sign));
TRACE("dioph_eq", tout << "eliminate var:" << j << " by using:";
TRACE("dio", tout << "eliminate var:" << j << " by using:";
print_entry(ei, tout) << std::endl;);
auto& column = m_e_matrix.m_columns[j];
auto it =
Expand Down Expand Up @@ -2262,16 +2273,16 @@ namespace lp {
SASSERT(c.var() != ei && entry_invariant(c.var()));
mpq coeff = m_e_matrix.get_val(c);
unsigned i = c.var();
TRACE("dioph_eq", tout << "before pivot entry:";
TRACE("dio", tout << "before pivot entry:";
print_entry(i, tout) << std::endl;);
m_sum_of_fixed[i] -= j_sign * coeff * e;
m_e_matrix.pivot_row_to_row_given_cell_with_sign(ei, c, j, j_sign);
// m_sum_of_fixed[i].m_l -= j_sign * coeff * e.m_l;
m_l_matrix.add_rows(-j_sign * coeff, ei, i);
TRACE("dioph_eq", tout << "after pivoting c_row:";
TRACE("dio", tout << "after pivoting c_row:";
print_entry(i, tout););
CTRACE(
"dioph_eq", !entry_invariant(i), tout << "invariant delta:"; {
"dio", !entry_invariant(i), tout << "invariant delta:"; {
print_term_o(get_term_from_entry(ei) -
fix_vars(open_ml(m_l_matrix.m_rows[ei])),
tout)
Expand All @@ -2287,7 +2298,7 @@ namespace lp {
// matrix m_l_matrix is not changed since it is a substitution of a fresh variable
void eliminate_var_in_f_with_term(const lar_term& t, unsigned j, int j_sign) {
SASSERT(abs(t.get_coeff(j)).is_one());
TRACE("dioph_eq", tout << "eliminate var:" << j << " by using:";
TRACE("dio", tout << "eliminate var:" << j << " by using:";
print_lar_term_L(t, tout) << std::endl;);
auto& column = m_e_matrix.m_columns[j];

Expand All @@ -2300,9 +2311,9 @@ namespace lp {
}

mpq coeff = m_e_matrix.get_val(c);
TRACE("dioph_eq", tout << "before pivot entry :"; print_entry(c.var(), tout) << std::endl;);
TRACE("dio", tout << "before pivot entry :"; print_entry(c.var(), tout) << std::endl;);
m_e_matrix.pivot_term_to_row_given_cell(t, c, j, j_sign);
TRACE("dioph_eq", tout << "after pivoting c_row:";
TRACE("dio", tout << "after pivoting c_row:";
print_entry(c.var(), tout););
SASSERT(entry_invariant(c.var()));
cell_to_process--;
Expand Down Expand Up @@ -2380,7 +2391,7 @@ namespace lp {
while (!q.empty()) {
unsigned xt = q.pop_front(); // xt is a fresh var
const lar_term& fresh_t = m_fresh_k2xt_terms.get_by_val(xt).first;
TRACE("dioph_eq", print_lar_term_L(fresh_t, tout););
TRACE("dio", print_lar_term_L(fresh_t, tout););
SASSERT(fresh_t.get_coeff(xt).is_minus_one());
if (!t.contains(xt))
continue;
Expand Down Expand Up @@ -2583,7 +2594,7 @@ namespace lp {
if (h == UINT_MAX) return false;
SASSERT(h == f_vector[ih]);
if (min_ahk.is_one()) {
TRACE("dioph_eq", tout << "push to S:\n"; print_entry(h, tout););
TRACE("dio", tout << "push to S:\n"; print_entry(h, tout););
move_entry_from_f_to_s(kh, h);
eliminate_var_in_f(h, kh, kh_sign);
if (ih != f_vector.size() - 1) {
Expand All @@ -2608,16 +2619,16 @@ namespace lp {
for (auto ci : m_infeas_explanation) {
ex.push_back(ci.ci());
}
TRACE("dioph_eq", lra.print_expl(tout, ex););
TRACE("dio", lra.print_expl(tout, ex););
return;
}
SASSERT(ex.empty());
TRACE("dioph_eq", tout << "conflict:";
TRACE("dio", tout << "conflict:";
print_entry(m_conflict_index, tout, true) << std::endl;);
for (auto ci : lra.flatten(explain_fixed_in_meta_term(m_l_matrix.m_rows[m_conflict_index]))) {
ex.push_back(ci);
}
TRACE("dioph_eq", lra.print_expl(tout, ex););
TRACE("dio", lra.print_expl(tout, ex););
}

// needed for the template bound_analyzer_on_row.h
Expand Down
2 changes: 1 addition & 1 deletion src/math/lp/lp_settings.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -260,7 +260,7 @@ struct lp_settings {
bool m_dio_enable_gomory_cuts = false;
bool m_dio_enable_hnf_cuts = true;
unsigned m_dio_branching_period = 100; // do branching rarely
unsigned m_dio_report_branch_with_term_tigthening_period = 4; // report the branch with term tigthening every 2 iterations
unsigned m_dio_report_branch_with_term_tigthening_period = 10000000;

public:
bool print_external_var_name() const { return m_print_external_var_name; }
Expand Down

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