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catch a conflict with a fractional sum of fixed variables in a term

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Signed-off-by: Lev Nachmanson <levnach@hotmail.com>
This commit is contained in:
Lev Nachmanson 2025-12-30 16:09:24 -10:00
parent 58462938fa
commit 17dffc67c9
1 changed files with 24 additions and 23 deletions
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47
src/math/lp/dioph_eq.cpp
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@ -929,12 +929,10 @@ namespace lp {
unsigned j = m_q.pop_front();
mpq alpha = get_coeff_in_e_row(ei, j);
if (alpha.is_zero()) continue;
if (m_k2s.has_key(j)) {
if (m_k2s.has_key(j))
substitute_on_q_with_entry_in_S(ei, j, alpha);
}
else {
else
substitute_with_fresh_def(ei, j, alpha);
}
}
}
bool term_is_in_range(const lar_term& t) const {
@ -952,6 +950,7 @@ namespace lp {
// adds entry i0 multiplied by coeff to entry i1
void add_two_entries(const mpq& coeff, unsigned i0, unsigned i1) {
SASSERT(coeff.is_int());
m_e_matrix.add_rows(coeff, i0, i1);
m_l_matrix.add_rows(coeff, i0, i1);
m_sum_of_fixed[i1] += coeff * m_sum_of_fixed[i0];
@ -966,7 +965,7 @@ namespace lp {
}
void recalculate_entry(unsigned ei) {
TRACE(dio, print_entry(ei, tout) << std::endl;);
TRACE(dio, print_entry(ei, tout, true) << std::endl;);
mpq& fixed_sum = m_sum_of_fixed[ei];
fixed_sum = mpq(0);
open_l_term_to_espace(ei, fixed_sum);
@ -985,9 +984,10 @@ namespace lp {
m_l_matrix.multiply_row(ei, denom);
m_e_matrix.multiply_row(ei, denom);
}
if (belongs_to_s(ei)) {
if (belongs_to_s(ei))
remove_from_S(ei);
}
TRACE(dio, tout << "recalculated entry:\n"; print_entry(ei, tout, true) << std::endl;);
}
void find_changed_terms_and_more_changed_rows() {
@ -1220,13 +1220,13 @@ namespace lp {
// The function returns true if and only if there is no conflict.
bool normalize_e_by_gcd(unsigned ei, mpq& g) {
mpq& e = m_sum_of_fixed[ei];
TRACE(dio, print_entry(ei, tout) << std::endl;);
g = gcd_of_coeffs(m_e_matrix.m_rows[ei], false);
TRACE(dio, print_entry(ei, tout, true) << std::endl;);
g = gcd_of_coeffs(m_e_matrix.m_rows[ei], true);
TRACE(dio, tout << "g:" << g << std::endl;);
if (g.is_zero() || g.is_one()) {
SASSERT(g.is_one() || e.is_zero());
return true;
}
TRACE(dio, tout << "g:" << g << std::endl;);
mpq c_g = e / g;
if (c_g.is_int()) {
for (auto& p : m_e_matrix.m_rows[ei]) {
@ -1234,15 +1234,14 @@ namespace lp {
}
m_sum_of_fixed[ei] = c_g;
// e.m_l /= g
for (auto& p : m_l_matrix.m_rows[ei]) {
for (auto& p : m_l_matrix.m_rows[ei])
p.coeff() /= g;
}
TRACE(dio, tout << "ep_m_e:";
print_entry(ei, tout) << std::endl;);
TRACE(dio, tout << "ep_m_e:"; print_entry(ei, tout, true) << std::endl;);
SASSERT(entry_invariant(ei));
return true;
}
TRACE(dio, tout << "false\n";);
// c_g is not integral
return false;
}
@ -1459,8 +1458,6 @@ namespace lp {
t1.add_monomial(mpq(1), j);
term_o rs = fix_vars(t1);
if (ls != rs) {
std::cout << "enabling trace dio\n";
enable_trace("dio");
TRACE(dio, tout << "ls:"; print_term_o(ls, tout) << "\n";
tout << "rs:"; print_term_o(rs, tout) << "\n";);
return false;
@ -2167,9 +2164,10 @@ namespace lp {
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;
TRACE(dio, print_term_o(open_ml(m_l_matrix.m_rows[ei]), tout << "l row " << ei << ":") << "\n";);
m_l_matrix.add_rows(-j_sign * coeff, ei, i);
TRACE(dio, tout << "after pivoting c_row:";
print_entry(i, tout););
print_entry(i, tout, true););
CTRACE(
dio, !entry_invariant(i), tout << "invariant delta:"; {
print_term_o(get_term_from_entry(ei) -
@ -2242,7 +2240,6 @@ namespace lp {
continue;
unsigned j = local_to_lar_solver(p.var());
if (is_fixed(j)) {
enable_trace("dio");
TRACE(dio, tout << "x" << j << "(local: " << "x" << p.var() << ") should not be fixed\nbad entry:"; print_entry(ei, tout) << "\n";);
return false;
}
@ -2251,8 +2248,6 @@ namespace lp {
term_o ls = term_to_lar_solver(remove_fresh_vars(get_term_from_entry(ei)));
mpq ls_val = get_term_value(ls);
if (!ls_val.is_zero()) {
std::cout << "ls_val is not zero\n";
enable_trace("dio");
TRACE(dio, {
tout << "get_term_from_entry(" << ei << "):";
print_term_o(get_term_from_entry(ei), tout) << std::endl;
@ -2270,7 +2265,6 @@ namespace lp {
}
bool ret = ls == fix_vars(open_ml(m_l_matrix.m_rows[ei]));
if (!ret) {
enable_trace("dio");
CTRACE(dio, !ret,
{
tout << "get_term_from_entry(" << ei << "):";
@ -2486,15 +2480,22 @@ namespace lp {
unsigned ei = f_vector[i];
SASSERT (belongs_to_f(ei));
if (m_e_matrix.m_rows[ei].size() == 0) {
if (m_sum_of_fixed[ei].is_zero()) {
if (m_sum_of_fixed[ei].is_zero())
continue;
}
else {
TRACE(dio, tout << "zero row with non_zero fixed sum conflict:\n"; print_entry(ei, tout, true) << std::endl;);
set_rewrite_conflict(ei, mpq(0));
return lia_move::conflict;
}
}
if (!m_sum_of_fixed[ei].is_int()) {
TRACE(dio, tout << "new conflict: early non-integral entry in S after move_entry_from_f_to_s\n";
print_entry(ei, tout) << std::endl;);
set_rewrite_conflict(ei, mpq(0));
return lia_move::conflict;
}
auto [ahk, k, k_sign, markovich_number] = find_minimal_abs_coeff(ei);
mpq gcd;
if (!normalize_e_by_gcd(ei, gcd)) {