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added some comments

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This commit is contained in:
Nikolaj Bjorner 2025-03-20 18:07:25 -10:00
parent 281512809d
commit 5260fb5077
1 changed files with 22 additions and 21 deletions
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43
src/math/lp/dioph_eq.cpp
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@ -506,7 +506,7 @@ namespace lp {
unsigned m_conflict_index = UINT_MAX; // the row index of the conflict
void reset_conflict() { m_conflict_index = UINT_MAX; }
bool has_conflict() const { return m_conflict_index != UINT_MAX; }
bool has_conflict_index() const { return m_conflict_index != UINT_MAX; }
void set_rewrite_conflict(unsigned idx) { SASSERT(idx != UINT_MAX); m_conflict_index = idx; lra.stats().m_dio_rewrite_conflicts++; }
unsigned m_max_of_branching_iterations = 0;
unsigned m_number_of_branching_calls;
@ -1658,7 +1658,7 @@ namespace lp {
lia_move tighten_bounds_for_non_trivial_gcd(const mpq& g, unsigned j,
bool is_upper) {
mpq rs;
bool is_strict;
bool is_strict = false;
u_dependency* b_dep = nullptr;
SASSERT(!g.is_zero());
@ -1679,10 +1679,14 @@ namespace lp {
return lia_move::undef;
}
// returns true only on a conflict
// returns true only on a conflict
bool tighten_bound_kind(const mpq& g, unsigned j, const mpq& rs, const mpq& rs_mod_g, bool upper) {
// Assume:
// rs_mod_g := (rs - m_c) % g
// rs_mod_g != 0
//
// In case of an upper bound we have
// xj = t = g*t_+ m_c <= rs, also, by definition fo rs_mod_g, for some integer k holds rs - m_c = k*g + rs_mod_g.
// xj = t = g*t_+ m_c <= rs, also, by definition of rs_mod_g, for some integer k holds rs - m_c = k*g + rs_mod_g.
// Then g*t_ <= rs - mc = k*g + rs_mod_g => g*t_ <= k*g = rs - m_c - rs_mod_g.
// Adding m_c to both parts gets us
// xj = g*t_ + m_c <= rs - rs_mod_g
@ -1696,8 +1700,7 @@ namespace lp {
mpq bound = upper ? rs - rs_mod_g : rs + g - rs_mod_g;
TRACE("dio", tout << "is upper:" << upper << std::endl;
tout << "new " << (upper ? "upper" : "lower")
<< " bound:" << bound << std::endl;);
tout << "new " << (upper ? "upper" : "lower") << " bound:" << bound << std::endl;);
SASSERT((upper && bound < lra.get_upper_bound(j).x) ||
(!upper && bound > lra.get_lower_bound(j).x));
@ -1710,8 +1713,8 @@ namespace lp {
for (const auto& p: fixed_part_of_the_term) {
SASSERT(is_fixed(p.var()));
if ((p.coeff() % g).is_zero()) {
// we can skip thise dependency,
// because the monomial p.coeff()*p.var() is null by modulo g, and it does not matter that p.var() is fixed.
// we can skip this dependency
// because the monomial p.coeff()*p.var() is 0 modulo g, and it does not matter that p.var() is fixed.
// We could have added p.coeff()*p.var() to t_, substructed the value of p.coeff()*p.var() from m_c and
// still get the same result.
TRACE("dio", tout << "skipped dep:\n"; print_deps(tout, lra.get_bound_constraint_witnesses_for_column(p.var())););
@ -1767,7 +1770,7 @@ namespace lp {
}
lia_move process_f(std_vector<unsigned>& f_vector) {
if (has_conflict())
if (has_conflict_index())
return lia_move::conflict;
lia_move r;
do {
@ -2156,7 +2159,7 @@ namespace lp {
bool first = true;
mpq ahk;
unsigned k = -1;
int k_sign;
int k_sign = 0;
mpq t;
for (const auto& p : m_e_matrix.m_rows[ei]) {
t = abs(p.coeff());
@ -2586,19 +2589,17 @@ namespace lp {
}
public:
void explain(explanation& ex) {
if (!has_conflict()) {
for (auto ci : m_infeas_explanation) {
ex.push_back(ci.ci());
}
TRACE("dio", lra.print_expl(tout, ex););
return;
}
SASSERT(ex.empty());
TRACE("dio", tout << "conflict:";
print_entry(m_conflict_index, tout, true) << std::endl;);
for (auto ci : lra.flatten(explain_fixed_in_meta_term(m_l_matrix.m_rows[m_conflict_index]))) {
ex.push_back(ci);
if (has_conflict_index()) {
TRACE("dio", print_entry(m_conflict_index, tout << "conflict:", true) << std::endl;);
for (auto ci : lra.flatten(explain_fixed_in_meta_term(m_l_matrix.m_rows[m_conflict_index])))
ex.push_back(ci);
}
else {
for (auto ci : m_infeas_explanation)
ex.push_back(ci.ci());
}
TRACE("dio", lra.print_expl(tout, ex););
}