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handle empty rows in m_e_matrix

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Signed-off-by: Lev Nachmanson <levnach@hotmail.com>
This commit is contained in:
Lev Nachmanson 2024-10-15 08:01:20 -07:00 committed by Lev Nachmanson
parent ba7268c895
commit 0f03e7560d
1 changed files with 31 additions and 13 deletions
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44
src/math/lp/dioph_eq.cpp
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@ -561,6 +561,10 @@ public:
return lia_move::conflict;
}
rewrite_eqs();
if (m_conflict_index != -1) {
lra.settings().stats().m_dio_conflicts++;
return lia_move::conflict;
}
}
TRACE("dioph_eq", print_S(tout););
// lia_move ret = tighten_with_S();
@ -756,31 +760,45 @@ public:
}
// k is the index of the index of the variable with the coefficient +-1 that is being substituted
void move_entry_from_f_to_s(unsigned k, std::list<unsigned>::iterator it) {
SASSERT(m_eprime[*it].m_entry_status == entry_status::F);
m_eprime[*it].m_entry_status = entry_status::S;
void move_entry_from_f_to_s(unsigned k, unsigned h) {
SASSERT(m_eprime[h].m_entry_status == entry_status::F);
m_eprime[h].m_entry_status = entry_status::S;
if (k >= m_k2s.size()) { // k is a fresh variable
m_k2s.resize(k+1, -1 );
}
m_s.push_back(*it);
TRACE("dioph_eq", tout << "removed " << *it << "th entry from F" << std::endl;);
m_k2s[k] = *it;
m_f.erase(it);
m_s.push_back(h);
TRACE("dioph_eq", tout << "removed " << h << "th entry from F" << std::endl;);
m_k2s[k] = h;
m_f.remove(h);
}
// this is the step 6 or 7 of the algorithm
void rewrite_eqs() {
auto eh_it = pick_eh();
auto& eprime_entry = m_eprime[*eh_it];
TRACE("dioph_eq", print_eprime_entry(*eh_it, tout););
unsigned h = -1;
auto it = m_f.begin();
while (it != m_f.end()) {
if (m_e_matrix.m_rows[m_eprime[*it].m_row_index].size() == 0)
if (m_eprime[*it].m_c.is_zero()) {
it = m_f.erase(it);
continue;
} else {
m_conflict_index = *it;
return;
}
h = *it;
break;
}
if (h == -1) return;
auto& eprime_entry = m_eprime[h];
TRACE("dioph_eq", print_eprime_entry(h, tout););
auto [ahk, k, k_sign] = find_minimal_abs_coeff(eprime_entry.m_row_index);
TRACE("dioph_eq", tout << "ahk:" << ahk << ", k:" << k << ", k_sign:" << k_sign << std::endl;);
if (ahk.is_one()) {
TRACE("dioph_eq", tout << "push to S:\n"; print_eprime_entry(*eh_it, tout););
move_entry_from_f_to_s(k, eh_it);
TRACE("dioph_eq", tout << "push to S:\n"; print_eprime_entry(h, tout););
move_entry_from_f_to_s(k, h);
eliminate_var_in_f(eprime_entry, k , k_sign);
} else {
fresh_var_step(*eh_it, k, ahk*mpq(k_sign));
fresh_var_step(h, k, ahk*mpq(k_sign));
}
}
public: