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enable cuts from proofs

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Signed-off-by: Lev Nachmanson <levnach@hotmail.com>
This commit is contained in:
Lev Nachmanson 2024-10-02 15:40:08 -07:00 • committed by Lev Nachmanson
parent 44fd0e48a8
commit 2ebb957cc8
5 changed files with 51 additions and 16 deletions
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35
src/math/lp/dioph_eq.cpp
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@ -127,7 +127,7 @@ namespace lp {
of variables in X and of integer constants showing the substitutions
*/
u_map<term_o> m_sigma;
public:
int_solver& lia;
lar_solver& lra;
@ -135,7 +135,7 @@ namespace lp {
// we start assigning with UINT_MAX and go down, print it as l(UINT_MAX - m_last_fresh_x_var)
unsigned m_last_fresh_x_var = UINT_MAX;
bool m_report_branch = false;
// set F
std::list<unsigned> m_f; // F = {λ(t):t in m_f}
@ -144,7 +144,6 @@ namespace lp {
vector<unsigned> m_k2s; // k is substituted by using equation in m_eprime[m_k2s[k]]
unsigned m_conflict_index = -1; // m_eprime[m_conflict_index] gives the conflict
imp(int_solver& lia, lar_solver& lra): lia(lia), lra(lra) {}
term_o row_to_term(const row_strip<mpq>& row) const {
@ -160,11 +159,13 @@ namespace lp {
}
void init() {
m_report_branch = false;
unsigned n_of_rows = lra.A_r().row_count();
m_k2s.clear();
m_k2s.resize(lra.column_count(), -1);
m_conflict_index = -1;
m_infeas_explanation.clear();
lia.get_term().clear();
auto all_vars_are_int = [this](const auto& row) {
for (const auto& p : row) {
@ -222,6 +223,8 @@ namespace lp {
return lra.print_expl(out, ex);
}
// returns true if no conflict is found and false otherwise
// this function devides all cooficients, and the free constant, of the ep.m_e by the gcd of all coefficients,
// it is needed by the next steps
bool normalize_e_by_gcd(eprime_pair& ep) {
TRACE("dioph_eq", print_term_o(ep.m_e, tout << "m_e:") << std::endl;
print_dep(tout << "m_l:", ep.m_l) << std::endl;
@ -235,7 +238,7 @@ namespace lp {
return true;
TRACE("dioph_eq", tout << "g:" << g << std::endl;);
mpq new_c = ep.m_e.c() / g;
if (new_c.is_int() == false) {
if (!new_c.is_int()) {
TRACE("dioph_eq",
print_term_o(ep.m_e, tout << "conflict m_e:") << std::endl;
tout << "g:" << g << std::endl;
@ -246,6 +249,21 @@ namespace lp {
print_term_o(t.m_value, tout) << std::endl;
}
);
/* We have ep.m_e/g = 0, or sum((coff_i/g)*x_i) + new_c = 0,
or sum((coeff_i/g)*x_i) = -new_c, where new_c is not an integer
Then sum((coeff_i/g)*x_i) <= floor(-new_c) or sum((coeff_i/g)*x_i) >= ceil(-new_c)
*/
if (lra.settings().stats().m_dio_conflicts % lra.settings().dio_cut_from_proof_period() == 0) {
// prepare int_solver for reporting
lar_term& t = lia.get_term();
for (auto& p: ep.m_e) {
t.add_monomial(p.coeff()/g, p.j());
}
lia.offset() = floor(-new_c);
lia.is_upper() = true;
m_report_branch = true;
TRACE("dioph_eq", tout << "prepare branch:"; print_lar_term_L(t, tout) << " <= " << lia.offset() << std::endl;);
}
return false;
} else {
for (auto& p: ep.m_e.coeffs()) {
@ -467,13 +485,20 @@ namespace lp {
lia_move check() {
init();
while(m_f.size()) {
if (!normalize_by_gcd())
if (!normalize_by_gcd()) {
lra.settings().stats().m_dio_conflicts++;
if (m_report_branch) {
m_report_branch = false;
return lia_move::branch;
}
return lia_move::conflict;
}
rewrite_eqs();
}
TRACE("dioph_eq", print_S(tout););
lia_move ret = tighten_with_S();
if (ret == lia_move::conflict) {
lra.settings().stats().m_dio_conflicts++;
return lia_move::conflict;
}
return lia_move::undef;