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disallow duplicates in a queue

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Signed-off-by: Lev Nachmanson <levnach@hotmail.com>
This commit is contained in:
Lev Nachmanson 2025-02-05 15:41:24 -08:00 committed by Lev Nachmanson
parent 7e02dfe484
commit 440d78f237
1 changed files with 45 additions and 34 deletions
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79
src/math/lp/dioph_eq.cpp
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@ -530,6 +530,32 @@ namespace lp {
m_s.undo_add_term_method(m_t);
}
};
struct protected_queue {
std::queue<unsigned> m_q;
indexed_uint_set m_in_q;
bool empty() const {
return m_q.empty();
}
unsigned size() const {
return m_q.size();
}
void push(unsigned j) {
if (m_in_q.contains(j)) return;
m_in_q.insert(j);
m_q.push(j);
}
unsigned pop_front() {
unsigned j = m_q.front();
m_q.pop();
SASSERT(m_in_q.contains(j));
m_in_q.remove(j);
return j;
}
};
struct undo_fixed_column : public trail {
imp& m_imp;
@ -757,7 +783,7 @@ namespace lp {
void subs_entry(unsigned ei) {
if (ei >= m_e_matrix.row_count()) return;
// q is the queue of variables that can be substituted in ei
std::queue<unsigned> q;
protected_queue q;
for (const auto& p: m_e_matrix.m_rows[ei]) {
if (can_substitute(p.var()))
q.push(p.var());
@ -767,54 +793,39 @@ namespace lp {
SASSERT(entry_invariant(ei));
}
void substitute_on_q_with_entry_in_S(std::queue<unsigned> & q, unsigned ei, unsigned j, const mpq & alpha, std::unordered_set<unsigned> & in_queue) {
void substitute_on_q_with_entry_in_S(protected_queue& q, unsigned ei, unsigned j, const mpq & alpha) {
unsigned ei_to_sub = m_k2s[j];
int sign_j = get_sign_in_e_row(ei_to_sub, j);
// we need to eliminate alpha*j in ei's row
add_two_entries(-mpq(sign_j)*alpha, ei_to_sub, ei);
for (const auto& p: m_e_matrix.m_rows[ei]) {
unsigned jj = p.var();
if (can_substitute(jj) && !contains(in_queue, jj)) {
if (can_substitute(jj))
q.push(jj);
in_queue.insert(jj);
}
}
}
void substitute_with_fresh_def(std::queue<unsigned> & q, unsigned ei, unsigned j, const mpq & alpha, std::unordered_set<unsigned> & in_queue) {
void substitute_with_fresh_def(protected_queue& q, unsigned ei, unsigned j, const mpq & alpha) {
const lar_term& sub_term = m_fresh_k2xt_terms.get_by_key(j);
SASSERT(sub_term.get_coeff(j).is_one());
// we need to eliminate alpha*j in ei's row
add_term_to_entry(- alpha, sub_term, ei);
for (const auto& p: m_e_matrix.m_rows[ei]) {
unsigned jj = p.var();
if (can_substitute(jj) && !contains(in_queue, jj)) {
if (can_substitute(jj))
q.push(jj);
in_queue.insert(jj);
}
}
}
// q is the queue of variables that can be substituted in ei
void substitute_on_q(std::queue<unsigned> & q, unsigned ei) {
// Track queued items
std::unordered_set<unsigned> in_queue;
// Initialize with the current queue contents
{
std::queue<unsigned> tmp = q;
while (!tmp.empty()) {
in_queue.insert(tmp.front());
tmp.pop();
}
}
void substitute_on_q(protected_queue & q, unsigned ei) {
while (!q.empty()) {
unsigned j = pop_front(q);
in_queue.erase(j);
unsigned j = q.pop_front();
mpq alpha = get_coeff_in_e_row(ei, j);
if (alpha.is_zero()) continue;
if (m_k2s.has_key(j)) {
substitute_on_q_with_entry_in_S(q, ei, j, alpha, in_queue);
substitute_on_q_with_entry_in_S(q, ei, j, alpha);
} else {
substitute_with_fresh_def(q, ei, j, alpha,in_queue);
substitute_with_fresh_def(q, ei, j, alpha);
}
}
}
@ -1172,7 +1183,7 @@ namespace lp {
}
void subs_front_in_indexed_vector_by_fresh(unsigned k, std::queue<unsigned> &q) {
void subs_front_in_indexed_vector_by_fresh(unsigned k, protected_queue &q) {
const lar_term& e = m_fresh_k2xt_terms.get_by_key(k);
TRACE("dioph_eq", tout << "k:" << k << ", in ";
print_term_o(create_term_from_ind_c(), tout) << std::endl;
@ -1206,7 +1217,7 @@ namespace lp {
}
}
void subs_front_in_indexed_vector_by_S(unsigned k, std::queue<unsigned> &q) {
void subs_front_in_indexed_vector_by_S(unsigned k, protected_queue& q) {
const mpq& e = m_sum_of_fixed[m_k2s[k]];
TRACE("dioph_eq", tout << "k:" << k << ", in ";
print_term_o(create_term_from_ind_c(), tout) << std::endl;
@ -1250,8 +1261,8 @@ namespace lp {
// The term giving the substitution is in form (+-)x_k + sum {a_i*x_i} + c = 0.
// We substitute x_k in t by (+-)coeff*(sum {a_i*x_i} + c), where coeff is
// the coefficient of x_k in t.
void subs_front_in_indexed_vector(std::queue<unsigned>& q) {
unsigned k = pop_front(q);
void subs_front_in_indexed_vector(protected_queue& q) {
unsigned k = q.pop_front();
if (m_indexed_work_vector[k].is_zero())
return;
// we might substitute with a term from S or a fresh term
@ -1306,13 +1317,13 @@ namespace lp {
}
template <typename T>
T pop_front(std::queue<T>& q) const {
T pop_front_of_queue(std::queue<T>& q) const {
T value = q.front();
q.pop();
return value;
}
void subs_indexed_vector_with_S(std::queue<unsigned>& q) {
void subs_indexed_vector_with_S_and_fresh(protected_queue& q) {
while (!q.empty())
subs_front_in_indexed_vector(q);
}
@ -1382,7 +1393,7 @@ namespace lp {
term_o term_to_tighten = lra.get_term(j); // copy the term aside
if (!all_vars_are_int(term_to_tighten))
return false;
std::queue<unsigned> q;
protected_queue q;
for (const auto& p : term_to_tighten) {
if (!lra.column_is_fixed(p.j()) &&
can_substitute(lar_solver_to_local(p.j())))
@ -1400,7 +1411,7 @@ namespace lp {
print_term_o(create_term_from_ind_c(), tout) << std::endl;
tout << "m_tmp_l:";
print_lar_term_L(m_term_with_index.to_term(), tout) << std::endl;);
subs_indexed_vector_with_S(q);
subs_indexed_vector_with_S_and_fresh(q);
// if(
// fix_vars(term_to_tighten + open_ml(m_tmp_l)) !=
// term_to_lar_solver(remove_fresh_vars(create_term_from_ind_c())))
@ -2142,14 +2153,14 @@ namespace lp {
term_o remove_fresh_vars(const term_o& tt) const {
term_o t = tt;
std::queue<unsigned> q;
protected_queue q;
for (const auto& p : t) {
if (var_is_fresh(p.j())) {
q.push(p.j());
}
}
while (!q.empty()) {
unsigned xt = pop_front(q); // xt is a fresh var
unsigned xt = q.pop_front(); // xt is a fresh var
const lar_term& fresh_t = m_fresh_k2xt_terms.get_by_val(xt);
TRACE("dioph_eq", print_lar_term_L(fresh_t, tout););
SASSERT(fresh_t.get_coeff(xt).is_minus_one());