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try markovich number

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Signed-off-by: Lev Nachmanson <levnach@hotmail.com>
This commit is contained in:
Lev Nachmanson 2025-02-07 22:27:25 -08:00 • committed by Lev Nachmanson
parent 3f2d2e8348
commit cec8dc2e6e
1 changed files with 60 additions and 24 deletions
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84
src/math/lp/dioph_eq.cpp
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@ -1602,8 +1602,30 @@ namespace lp {
return dep;
}
void fill_f_vector(std_vector<unsigned> & f_vector) {
for (unsigned ei = 0; ei < m_e_matrix.row_count(); ei++) {
if (belongs_to_s(ei)) continue;
if (m_e_matrix.m_rows[ei].size() == 0) {
if (m_sum_of_fixed[ei].is_zero()) {
continue;
} else {
m_conflict_index = ei;
return;
}
}
f_vector.push_back(ei);
}
}
lia_move process_f() {
while (rewrite_eqs()) {}
std_vector<unsigned> f_vector;
fill_f_vector(f_vector);
if (m_conflict_index != UINT_MAX) {
lra.stats().m_dio_rewrite_conflicts++;
return lia_move::conflict;
}
while (rewrite_eqs(f_vector)) {}
if (m_conflict_index != UINT_MAX) {
lra.stats().m_dio_rewrite_conflicts++;
@ -1977,7 +1999,16 @@ namespace lp {
}
}
std::tuple<mpq, unsigned, int> find_minimal_abs_coeff(unsigned ei) const {
unsigned find_markovich_number(unsigned k) {
unsigned r = 0;
for (const auto & p: m_e_matrix.m_columns[k]) {
r += m_e_matrix.m_rows[p.var()].size();
}
return r;
}
std::tuple<mpq, unsigned, int, unsigned> find_minimal_abs_coeff(unsigned ei) {
bool first = true;
mpq ahk;
unsigned k;
@ -1995,7 +2026,7 @@ namespace lp {
}
}
return std::make_tuple(ahk, k, k_sign);
return std::make_tuple(ahk, k, k_sign, find_markovich_number(k));
}
term_o get_term_to_subst(const term_o& eh, unsigned k, int k_sign) {
@ -2322,14 +2353,19 @@ namespace lp {
// this is the step 6 or 7 of the algorithm
// returns true if an equlity was rewritten and false otherwise
bool rewrite_eqs() {
bool rewrite_eqs(std_vector<unsigned>& f_vector) {
if (f_vector.size() == 0)
return false;
unsigned h = -1;
unsigned n = 0; // number of choices for a fresh variable
mpq the_smallest_ahk;
unsigned kh;
int kh_sign;
for (unsigned ei = 0; ei < m_e_matrix.row_count(); ei++) {
if (belongs_to_s(ei)) continue;
unsigned h_markovich_number;
unsigned ih; // f_vector[ih] = h
for (unsigned i = 0; i < f_vector.size(); i++) {
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()) {
continue;
@ -2339,45 +2375,45 @@ namespace lp {
}
}
auto [ahk, k, k_sign] = find_minimal_abs_coeff(ei);
if (ahk.is_one()) {
TRACE("dioph_eq", tout << "push to S:\n"; print_entry(ei, tout););
move_entry_from_f_to_s(k, ei);
eliminate_var_in_f(ei, k, k_sign);
return true;
}
auto [ahk, k, k_sign, markovich_number] = find_minimal_abs_coeff(ei);
mpq gcd;
if (!normalize_e_by_gcd(ei, gcd)) {
m_conflict_index = ei;
return false;
}
if (!gcd.is_one()) {
if (!gcd.is_one())
ahk /= gcd;
if (ahk.is_one()) {
TRACE("dioph_eq", tout << "push to S:\n"; print_entry(ei, tout););
move_entry_from_f_to_s(k, ei);
eliminate_var_in_f(ei, k, k_sign);
return true;
}
}
if (n == 0 || the_smallest_ahk > ahk) {
ih = i;
n = 1;
the_smallest_ahk = ahk;
h = ei;
kh = k;
kh_sign = k_sign;
h_markovich_number = markovich_number;
continue;
}
if (the_smallest_ahk == ahk && lra.settings().random_next() % (++n) == 0) {
if (the_smallest_ahk == ahk && h_markovich_number > markovich_number) {
ih = i;
h = ei;
kh = k;
kh_sign = k_sign;
h_markovich_number = markovich_number;
}
}
if (h == UINT_MAX) return false;
SASSERT(!the_smallest_ahk.is_one());
fresh_var_step(h, kh, the_smallest_ahk * mpq(kh_sign));
SASSERT(h == f_vector[ih]);
if (the_smallest_ahk.is_one()) {
TRACE("dioph_eq", 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) {
f_vector[ih] = f_vector.back();
}
f_vector.pop_back();
} else
fresh_var_step(h, kh, the_smallest_ahk * mpq(kh_sign));
return true;
}