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work on tighten_with_S

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Signed-off-by: Lev Nachmanson <levnach@hotmail.com>
This commit is contained in:
Lev Nachmanson 2024-09-04 09:20:21 -07:00 • committed by Lev Nachmanson
parent f0b5cd1066
commit 1408fe60ab
2 changed files with 158 additions and 48 deletions
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188
src/math/lp/dioph_eq.cpp
View file

@ -35,11 +35,11 @@ namespace lp {
}
friend term_o operator*(const mpq& k, const term_o& term) {
term_o r;
for (const auto& p : term)
r.add_monomial(p.coeff()*k, p.j());
r.c() = k*term.c();
return r;
term_o r;
for (const auto& p : term)
r.add_monomial(p.coeff()*k, p.j());
r.c() = k*term.c();
return r;
}
#if Z3DEBUG
friend bool operator== (const term_o & a, const term_o& b) {
@ -58,7 +58,7 @@ namespace lp {
};
std::ostream& print_S(std::ostream & out) const {
out << "S:\n";
out << "S:\n";
for (unsigned i : m_s) {
out << "x" << m_eprime[i].m_e.j() << " ->\n";
print_eprime_entry(i, out);
@ -103,9 +103,9 @@ namespace lp {
if (!term.c().is_zero()) {
if (term.c().is_pos())
out << " + " << term.c();
out << " + " << term.c();
else
out << " - " << -term.c();
out << " - " << -term.c();
}
out << ", j():"<< term.j();
return out;
@ -137,6 +137,7 @@ namespace lp {
std::list<unsigned> m_f; // F = {λ(t):t in m_f}
// set S
std::list<unsigned> m_s; // S = {λ(t): t in m_s}
u_map<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
@ -179,9 +180,9 @@ namespace lp {
continue;
}
eprime_pair pair = {t, lar_term(i)};
m_f.push_back(m_f.size());
m_f.push_back(static_cast<unsigned>(m_f.size()));
m_eprime.push_back(pair);
TRACE("dioph_eq", print_eprime_entry(m_f.size() - 1, tout););
TRACE("dioph_eq", print_eprime_entry(static_cast<unsigned>(m_f.size()) - 1, tout););
}
}
@ -189,11 +190,11 @@ namespace lp {
mpq gcd_of_coeffs(const term_o& t) {
mpq g(0);
for (const auto & p : t) {
if (g.is_zero()) {
if (g.is_zero())
g = abs(p.coeff());
} else {
else
g = gcd(g, p.coeff());
}
if (g.is_one()) break;
}
return g;
}
@ -214,7 +215,7 @@ namespace lp {
if (new_c.is_int() == false) {
TRACE("dioph_eq",
print_term_o(ep.m_e, tout << "conflict m_e:") << std::endl;
tout << "g:" << g << std::endl;
tout << "g:" << g << std::endl;
print_lar_term_L(ep.m_l, tout << "m_l:") << std::endl;
for (const auto & p: ep.m_l) {
tout << p.coeff() << "("; print_term_o(m_eprime[p.j()].m_e, tout) << ")"<< std::endl;
@ -222,7 +223,7 @@ namespace lp {
tout << "S:\n";
for (const auto& t : m_sigma) {
tout << "x" << t.m_key << " -> ";
print_term_o(t.m_value, tout) << std::endl;
print_term_o(t.m_value, tout) << std::endl;
}
);
return false;
@ -233,9 +234,9 @@ namespace lp {
ep.m_e.c() = new_c;
ep.m_l *= (1/g);
TRACE("dioph_eq",
tout << "ep_m_e:"; print_term_o(ep.m_e, tout) << std::endl;
tout << "ep.ml:";
print_lar_term_L(ep.m_l, tout ) << std::endl;);
tout << "ep_m_e:"; print_term_o(ep.m_e, tout) << std::endl;
tout << "ep.ml:";
print_lar_term_L(ep.m_l, tout ) << std::endl;);
}
return true;
@ -250,6 +251,91 @@ namespace lp {
}
return true;
}
void init_term_from_constraint(term_o& t, const lar_base_constraint& c) {
for (const auto& p: c.coeffs()) {
t.add_monomial(p.first, p.second);
}
t.c() = - c.rhs();
}
void subs_k(const eprime_pair& e, unsigned k, term_o& t, std::queue<unsigned> & q) {
const mpq& k_coeff = e.m_e.get_coeff(k);
bool is_one = k_coeff.is_one();
SASSERT(is_one || k_coeff.is_minus_one());
t.erase_var(k);
if (is_one) {
for (const auto& p: e.m_e) {
if (p.j() == k) continue;
t.add_monomial(-p.coeff(), p.j());
if (m_k2s.contains(p.j()))
q.push(p.j());
}
t.c() -= e.m_e.c();
} else { // k_coeff is -1
for (const auto& p: e.m_e) {
if (p.j() == k) continue;
t.add_monomial(p.coeff(), p.j());
if (m_k2s.contains(p.j()))
q.push(p.j());
}
t.c() += e.m_e.c();
}
}
void process_q_with_S(std::queue<unsigned> &q, term_o& t, const lar_base_constraint& c) {
while (!q.empty()) {
unsigned k = q.front();
TRACE("dioph_eq", tout << "k:" << k << std::endl;);
q.pop();
const eprime_pair& e = m_eprime[m_k2s[k]];
TRACE("dioph_eq", tout << "k:" << k << " in: "; print_eprime_entry(m_k2s[k], tout) << std::endl;);
subs_k(e, k, t, q);
}
TRACE("dioph_eq", tout << "substituted t:"; print_term_o(t, tout) << std::endl;);
}
void tighten_with_S(const lar_base_constraint& c) {
TRACE("dioph_eq", tout << "constraint:"; lra.constraints().display(tout, c) << std::endl;);
SASSERT(c.is_active());
term_o t;
std::queue<unsigned> q;
for (const auto& p: c.coeffs()) {
if (m_k2s.contains(p.second))
q.push(p.second);
}
if (q.empty()) return;
init_term_from_constraint(t, c);
TRACE("dioph_eq", tout << "t:"; print_term_o(t, tout) << std::endl;);
process_q_with_S(q, t, c);
TRACE("dioph_eq", tout << "tighten:"; print_term_o(t, tout) << std::endl;);
mpq g = gcd_of_coeffs(t);
if (g.is_one()) return;
mpq new_c = t.c() / g;
if (new_c.is_int()) return;
std::cout << "."; return;
if (c.kind() == lconstraint_kind::EQ) {
TRACE("dioph_eq", tout << "conflict:" <<std::endl;);
NOT_IMPLEMENTED_YET();
} else if (c.kind() == lconstraint_kind::GE) {
for (auto& p: t.coeffs()) {
p.m_value /= g;
}
t.c() = ceil(new_c);
} else {
for (auto& p: t.coeffs()) {
p.m_value /= g;
}
t.c() = floor(new_c);
}
TRACE("dioph_eq", tout << "tighten/g:"; print_term_o(t, tout) << std::endl;);
NOT_IMPLEMENTED_YET();
}
lia_move tighten_with_S() {
for (const auto& c: lra.constraints().active()) {
tighten_with_S(c);
}
return lia_move::undef;
}
lia_move check() {
init();
@ -259,8 +345,8 @@ namespace lp {
rewrite_eqs();
}
TRACE("dioph_eq", print_S(tout););
//NOT_IMPLEMENTED_YET();
return lia_move::sat;
return tighten_with_S();
}
std::list<unsigned>::iterator pick_eh() {
return m_f.begin(); // TODO: make a smarter joice
@ -281,9 +367,12 @@ namespace lp {
const mpq& k_coeff = e.get_coeff(k);
TRACE("dioph_eq", print_eprime_entry(e_index, tout << "before:") << std::endl;
tout << "k_coeff:" << k_coeff << std::endl;);
tout << "k_coeff:" << k_coeff << std::endl;);
if (!l_term.is_empty()) {
add_operator(m_eprime[e_index].m_l, -k_sign*k_coeff, l_term);
if (k_sign == 1)
add_operator(m_eprime[e_index].m_l, -k_coeff, l_term);
else
add_operator(m_eprime[e_index].m_l, k_coeff, l_term);
}
e.substitute(k_subst, k);
TRACE("dioph_eq", print_eprime_entry(e_index, tout << "after :") << std::endl;);
@ -369,7 +458,7 @@ namespace lp {
print_eprime_entry(m_eprime.size()-1, tout););
substitute_var_on_f(k, 1, k_subs, xt_entry.m_l, e_index);
// the term to eliminate the fresh variable
// the term to eliminate the fresh variable
term_o xt_subs = xt_term.clone();
xt_subs.add_monomial(mpq(1), xt);
TRACE("dioph_eq", tout << "xt_subs: x~"<< fresh_index(xt) << " -> "; print_term_o(xt_subs, tout) << std::endl;);
@ -377,11 +466,19 @@ namespace lp {
}
std::ostream& print_eprime_entry(unsigned i, std::ostream& out) const {
out << "m_eprime[" << i << "]:{\n";
print_term_o(m_eprime[i].m_e, out << "\tm_e:") << "," << std::endl;
print_lar_term_L(m_eprime[i].m_l, out<< "\tm_l:") << "\n}"<< std::endl;
return out;
print_term_o(m_eprime[i].m_e, out << "\tm_e:") << "," << std::endl;
print_lar_term_L(m_eprime[i].m_l, out<< "\tm_l:") << "\n}"<< std::endl;
return out;
}
// this is the step 6 or 7 of the algorithm
// k is the index of the index of the variable with the coefficient +-1 that is being substituted
void move_from_f_to_s(unsigned k, std::list<unsigned>::iterator it) {
m_s.push_back(*it);
m_k2s.insert(k, *it);
m_f.erase(it);
}
// 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];
@ -392,8 +489,7 @@ namespace lp {
if (ahk.is_one()) {
eprime_entry.m_e.j() = k;
TRACE("dioph_eq", tout << "push to S:\n"; print_eprime_entry(*eh_it, tout););
m_s.push_back(*eh_it);
m_f.erase(eh_it);
move_from_f_to_s(k, eh_it);
eliminate_var_in_f(eprime_entry, k , k_sign);
} else {
fresh_var_step(*eh_it, k);
@ -416,25 +512,25 @@ namespace lp {
unsigned fresh_index(unsigned j) const {return UINT_MAX - j;}
void remove_fresh_variables(term_o& t) {
std::queue<unsigned> q;
for (auto p : t) {
if (is_fresh_var(p.j())) {
q.push(p.j());
}
}
CTRACE("dioph_eq_fresh", q.empty() == false, print_term_o(t, tout)<< std::endl);
while (!q.empty()) {
unsigned j = q.front();
q.pop();
const term_o& sub_t = m_sigma.find(j);
TRACE("dioph_eq_fresh", tout << "x~" << fresh_index(j) << "; sub_t:"; print_term_o(sub_t, tout) << std::endl;);
t.substitute(sub_t, j);
TRACE("dioph_eq_fresh", tout << "sub_t:"; print_term_o(sub_t, tout) << std::endl;
tout << "after sub:";print_term_o(t, tout) << std::endl;);
for (auto p : sub_t)
if (is_fresh_var(p.j()) && t.contains(p.j()))
std::queue<unsigned> q;
for (auto p : t) {
if (is_fresh_var(p.j())) {
q.push(p.j());
}
}
CTRACE("dioph_eq_fresh", q.empty() == false, print_term_o(t, tout)<< std::endl);
while (!q.empty()) {
unsigned j = q.front();
q.pop();
const term_o& sub_t = m_sigma.find(j);
TRACE("dioph_eq_fresh", tout << "x~" << fresh_index(j) << "; sub_t:"; print_term_o(sub_t, tout) << std::endl;);
t.substitute(sub_t, j);
TRACE("dioph_eq_fresh", tout << "sub_t:"; print_term_o(sub_t, tout) << std::endl;
tout << "after sub:";print_term_o(t, tout) << std::endl;);
for (auto p : sub_t)
if (is_fresh_var(p.j()) && t.contains(p.j()))
q.push(p.j());
}
}
}
bool is_fresh_var(unsigned j) const {

18
src/math/lp/lar_term.h
View file

@ -59,7 +59,6 @@ public:
}
}
void add_var(lpvar j) {
rational c(1);
add_monomial(c, j);
@ -71,10 +70,15 @@ public:
unsigned size() const { return static_cast<unsigned>(m_coeffs.size()); }
u_map<mpq> const & coeffs() const {
u_map<mpq> const &coeffs() const {
return m_coeffs;
}
u_map<mpq> &coeffs() {
return m_coeffs;
}
void subst_by_term(const lar_term& t, unsigned term_column) {
auto it = this->m_coeffs.find_core(term_column);
if (it == nullptr) return;
@ -138,6 +142,16 @@ public:
SASSERT(it != nullptr);
return it->get_data().m_value;
}
mpq & get_coeff(unsigned j){
auto* it = m_coeffs.find_core(j);
SASSERT(it != nullptr);
return it->get_data().m_value;
}
void erase_var(unsigned j) {
m_coeffs.erase(j);
}
// the monomial ax[j] is substituted by ax[k]
void subst_index(unsigned j, unsigned k) {
auto* it = m_coeffs.find_core(j);