mirrors/z3
3
0
Fork 0
mirror of https://github.com/Z3Prover/z3 synced 2025-04-29 20:05:51 +00:00
Code Activity

refactor monotone lemmas out of core

Browse source 
Signed-off-by: Lev Nachmanson <levnach@hotmail.com>
This commit is contained in:
Lev Nachmanson 2019-04-16 11:29:46 -07:00
parent 8331207b81
commit facf0b80c0
5 changed files with 351 additions and 427 deletions
Download patch file Download diff file Expand all files Collapse all files

1
src/util/lp/CMakeLists.txt
View file

@ -27,6 +27,7 @@ z3_add_component(lp
nla_basics_lemmas.cpp
nla_common.cpp
nla_core.cpp
nla_monotone_lemmas.cpp
nla_order_lemmas.cpp
nla_solver.cpp
nra_solver.cpp

407
src/util/lp/nla_core.cpp
View file

@ -26,7 +26,8 @@ core::core(lp::lar_solver& s) :
m_lar_solver(s),
m_tangents(this),
m_basics(this),
m_order(this) {
m_order(this),
m_monotone(this) {
}
bool core::compare_holds(const rational& ls, llc cmp, const rational& rs) const {
@ -1324,14 +1325,6 @@ bool core:: has_zero_factor(const factorization& factorization) const {
return false;
}
template <typename T>
bool core:: has_zero(const T& product) const {
for (const rational & t : product) {
if (t.is_zero())
return true;
}
return false;
}
template <typename T>
bool core:: mon_has_zero(const T& product) const {
@ -1342,96 +1335,7 @@ bool core:: mon_has_zero(const T& product) const {
return false;
}
// x != 0 or y = 0 => |xy| >= |y|
void core::proportion_lemma_model_based(const rooted_mon& rm, const factorization& factorization) {
rational rmv = abs(vvr(rm));
if (rmv.is_zero()) {
SASSERT(has_zero_factor(factorization));
return;
}
int factor_index = 0;
for (factor f : factorization) {
if (abs(vvr(f)) > rmv) {
generate_pl(rm, factorization, factor_index);
return;
}
factor_index++;
}
}
// x != 0 or y = 0 => |xy| >= |y|
bool core:: proportion_lemma_derived(const rooted_mon& rm, const factorization& factorization) {
return false;
rational rmv = abs(vvr(rm));
if (rmv.is_zero()) {
SASSERT(has_zero_factor(factorization));
return false;
}
int factor_index = 0;
for (factor f : factorization) {
if (abs(vvr(f)) > rmv) {
generate_pl(rm, factorization, factor_index);
return true;
}
factor_index++;
}
return false;
}
void core::basic_lemma_for_mon_model_based(const rooted_mon& rm) {
TRACE("nla_solver_bl", tout << "rm = "; print_rooted_monomial(rm, tout););
if (vvr(rm).is_zero()) {
for (auto factorization : factorization_factory_imp(rm, *this)) {
if (factorization.is_empty())
continue;
basic_lemma_for_mon_zero_model_based(rm, factorization);
basic_lemma_for_mon_neutral_model_based(rm, factorization);
}
} else {
for (auto factorization : factorization_factory_imp(rm, *this)) {
if (factorization.is_empty())
continue;
basic_lemma_for_mon_non_zero_model_based(rm, factorization);
basic_lemma_for_mon_neutral_model_based(rm, factorization);
proportion_lemma_model_based(rm, factorization) ;
}
}
}
bool core:: basic_lemma_for_mon_derived(const rooted_mon& rm) {
if (var_is_fixed_to_zero(var(rm))) {
for (auto factorization : factorization_factory_imp(rm, *this)) {
if (factorization.is_empty())
continue;
if (basic_lemma_for_mon_zero(rm, factorization) ||
basic_lemma_for_mon_neutral_derived(rm, factorization)) {
explain(factorization, current_expl());
return true;
}
}
} else {
for (auto factorization : factorization_factory_imp(rm, *this)) {
if (factorization.is_empty())
continue;
if (basic_lemma_for_mon_non_zero_derived(rm, factorization) ||
basic_lemma_for_mon_neutral_derived(rm, factorization) ||
proportion_lemma_derived(rm, factorization)) {
explain(factorization, current_expl());
return true;
}
}
}
return false;
}
// Use basic multiplication properties to create a lemma
// for the given monomial.
// "derived" means derived from constraints - the alternative is model based
void core::basic_lemma_for_mon(const rooted_mon& rm, bool derived) {
if (derived)
basic_lemma_for_mon_derived(rm);
else
basic_lemma_for_mon_model_based(rm);
}
template bool core::mon_has_zero<monomial>(const monomial& product) const;
void core::init_rm_to_refine() {
if (!m_rm_table.to_refine().empty())
@ -1891,26 +1795,6 @@ void core::maybe_add_a_factor(lpvar i,
}
std::vector<rational> core::get_sorted_key(const rooted_mon& rm) const {
std::vector<rational> r;
for (unsigned j : rm.vars()) {
r.push_back(abs(vvr(j)));
}
std::sort(r.begin(), r.end());
return r;
}
void core::print_monotone_array(const vector<std::pair<std::vector<rational>, unsigned>>& lex_sorted,
std::ostream& out) const {
out << "Monotone array :\n";
for (const auto & t : lex_sorted ){
out << "(";
print_vector(t.first, out);
out << "), rm[" << t.second << "]" << std::endl;
}
out << "}";
}
// Returns rooted monomials by arity
std::unordered_map<unsigned, unsigned_vector> core::get_rm_by_arity() {
std::unordered_map<unsigned, unsigned_vector> m;
@ -1926,267 +1810,11 @@ std::unordered_map<unsigned, unsigned_vector> core::get_rm_by_arity() {
}
bool core::uniform_le(const std::vector<rational>& a,
const std::vector<rational>& b,
unsigned & strict_i) const {
SASSERT(a.size() == b.size());
strict_i = -1;
bool z_b = false;
for (unsigned i = 0; i < a.size(); i++) {
if (a[i] > b[i]){
return false;
}
SASSERT(!a[i].is_neg());
if (a[i] < b[i]){
strict_i = i;
} else if (b[i].is_zero()) {
z_b = true;
}
}
if (z_b) {strict_i = -1;}
return true;
}
vector<std::pair<rational, lpvar>> core::get_sorted_key_with_vars(const rooted_mon& a) const {
vector<std::pair<rational, lpvar>> r;
for (lpvar j : a.vars()) {
r.push_back(std::make_pair(abs(vvr(j)), j));
}
std::sort(r.begin(), r.end(), [](const std::pair<rational, lpvar>& a,
const std::pair<rational, lpvar>& b) {
return
a.first < b.first ||
(a.first == b.first &&
a.second < b.second);
});
return r;
}
void core::negate_abs_a_le_abs_b(lpvar a, lpvar b, bool strict) {
rational av = vvr(a);
rational as = rational(nla::rat_sign(av));
rational bv = vvr(b);
rational bs = rational(nla::rat_sign(bv));
TRACE("nla_solver", tout << "av = " << av << ", bv = " << bv << "\n";);
SASSERT(as*av <= bs*bv);
llc mod_s = strict? (llc::LE): (llc::LT);
mk_ineq(as, a, mod_s); // |a| <= 0 || |a| < 0
if (a != b) {
mk_ineq(bs, b, mod_s); // |b| <= 0 || |b| < 0
mk_ineq(as, a, -bs, b, llc::GT); // negate |aj| <= |bj|
}
}
void core::negate_abs_a_lt_abs_b(lpvar a, lpvar b) {
rational av = vvr(a);
rational as = rational(nla::rat_sign(av));
rational bv = vvr(b);
rational bs = rational(nla::rat_sign(bv));
TRACE("nla_solver", tout << "av = " << av << ", bv = " << bv << "\n";);
SASSERT(as*av < bs*bv);
mk_ineq(as, a, llc::LT); // |aj| < 0
mk_ineq(bs, b, llc::LT); // |bj| < 0
mk_ineq(as, a, -bs, b, llc::GE); // negate |aj| < |bj|
}
// a < 0 & b < 0 => a < b
void core::assert_abs_val_a_le_abs_var_b(
const rooted_mon& a,
const rooted_mon& b,
bool strict) {
lpvar aj = var(a);
lpvar bj = var(b);
rational av = vvr(aj);
rational as = rational(nla::rat_sign(av));
rational bv = vvr(bj);
rational bs = rational(nla::rat_sign(bv));
// TRACE("nla_solver", tout << "rmv = " << rmv << ", jv = " << jv << "\n";);
mk_ineq(as, aj, llc::LT); // |aj| < 0
mk_ineq(bs, bj, llc::LT); // |bj| < 0
mk_ineq(as, aj, -bs, bj, strict? llc::LT : llc::LE); // |aj| < |bj|
}
// strict version
void core::generate_monl_strict(const rooted_mon& a,
const rooted_mon& b,
unsigned strict) {
add_empty_lemma();
auto akey = get_sorted_key_with_vars(a);
auto bkey = get_sorted_key_with_vars(b);
SASSERT(akey.size() == bkey.size());
for (unsigned i = 0; i < akey.size(); i++) {
if (i != strict) {
negate_abs_a_le_abs_b(akey[i].second, bkey[i].second, true);
} else {
mk_ineq(b[i], llc::EQ);
negate_abs_a_lt_abs_b(akey[i].second, bkey[i].second);
}
}
assert_abs_val_a_le_abs_var_b(a, b, true);
explain(a, current_expl());
explain(b, current_expl());
TRACE("nla_solver", print_lemma(tout););
}
// not a strict version
void core::generate_monl(const rooted_mon& a,
const rooted_mon& b) {
TRACE("nla_solver", tout <<
"a = "; print_rooted_monomial_with_vars(a, tout) << "\n:";
tout << "b = "; print_rooted_monomial_with_vars(a, tout) << "\n:";);
add_empty_lemma();
auto akey = get_sorted_key_with_vars(a);
auto bkey = get_sorted_key_with_vars(b);
SASSERT(akey.size() == bkey.size());
for (unsigned i = 0; i < akey.size(); i++) {
negate_abs_a_le_abs_b(akey[i].second, bkey[i].second, false);
}
assert_abs_val_a_le_abs_var_b(a, b, false);
explain(a, current_expl());
explain(b, current_expl());
TRACE("nla_solver", print_lemma(tout););
}
bool core:: monotonicity_lemma_on_lex_sorted_rm_upper(const vector<std::pair<std::vector<rational>, unsigned>>& lex_sorted, unsigned i, const rooted_mon& rm) {
const rational v = abs(vvr(rm));
const auto& key = lex_sorted[i].first;
TRACE("nla_solver", tout << "rm = ";
print_rooted_monomial_with_vars(rm, tout); tout << "i = " << i << std::endl;);
for (unsigned k = i + 1; k < lex_sorted.size(); k++) {
const auto& p = lex_sorted[k];
const rooted_mon& rmk = m_rm_table.rms()[p.second];
const rational vk = abs(vvr(rmk));
TRACE("nla_solver", tout << "rmk = ";
print_rooted_monomial_with_vars(rmk, tout);
tout << "\n";
tout << "vk = " << vk << std::endl;);
if (vk > v) continue;
unsigned strict;
if (uniform_le(key, p.first, strict)) {
if (static_cast<int>(strict) != -1 && !has_zero(key)) {
generate_monl_strict(rm, rmk, strict);
return true;
} else {
if (vk < v) {
generate_monl(rm, rmk);
return true;
}
}
}
}
return false;
}
bool core:: monotonicity_lemma_on_lex_sorted_rm_lower(const vector<std::pair<std::vector<rational>, unsigned>>& lex_sorted, unsigned i, const rooted_mon& rm) {
const rational v = abs(vvr(rm));
const auto& key = lex_sorted[i].first;
TRACE("nla_solver", tout << "rm = ";
print_rooted_monomial_with_vars(rm, tout); tout << "i = " << i << std::endl;);
for (unsigned k = i; k-- > 0;) {
const auto& p = lex_sorted[k];
const rooted_mon& rmk = m_rm_table.rms()[p.second];
const rational vk = abs(vvr(rmk));
TRACE("nla_solver", tout << "rmk = ";
print_rooted_monomial_with_vars(rmk, tout);
tout << "\n";
tout << "vk = " << vk << std::endl;);
if (vk < v) continue;
unsigned strict;
if (uniform_le(p.first, key, strict)) {
TRACE("nla_solver", tout << "strict = " << strict << std::endl;);
if (static_cast<int>(strict) != -1) {
generate_monl_strict(rmk, rm, strict);
return true;
} else {
SASSERT(key == p.first);
if (vk < v) {
generate_monl(rmk, rm);
return true;
}
}
}
}
return false;
}
bool core:: monotonicity_lemma_on_lex_sorted_rm(const vector<std::pair<std::vector<rational>, unsigned>>& lex_sorted, unsigned i, const rooted_mon& rm) {
return monotonicity_lemma_on_lex_sorted_rm_upper(lex_sorted, i, rm)
|| monotonicity_lemma_on_lex_sorted_rm_lower(lex_sorted, i, rm);
}
bool core:: rm_check(const rooted_mon& rm) const {
return check_monomial(m_monomials[rm.orig_index()]);
}
bool core::monotonicity_lemma_on_lex_sorted(const vector<std::pair<std::vector<rational>, unsigned>>& lex_sorted) {
for (unsigned i = 0; i < lex_sorted.size(); i++) {
unsigned rmi = lex_sorted[i].second;
const rooted_mon& rm = m_rm_table.rms()[rmi];
TRACE("nla_solver", print_rooted_monomial(rm, tout); tout << "\n, rm_check = " << rm_check(rm); tout << std::endl;);
if ((!rm_check(rm)) && monotonicity_lemma_on_lex_sorted_rm(lex_sorted, i, rm))
return true;
}
return false;
}
bool core:: monotonicity_lemma_on_rms_of_same_arity(const unsigned_vector& rms) {
vector<std::pair<std::vector<rational>, unsigned>> lex_sorted;
for (unsigned i : rms) {
lex_sorted.push_back(std::make_pair(get_sorted_key(m_rm_table.rms()[i]), i));
}
std::sort(lex_sorted.begin(), lex_sorted.end(),
[](const std::pair<std::vector<rational>, unsigned> &a,
const std::pair<std::vector<rational>, unsigned> &b) {
return a.first < b.first;
});
TRACE("nla_solver", print_monotone_array(lex_sorted, tout););
return monotonicity_lemma_on_lex_sorted(lex_sorted);
}
void core::monotonicity_lemma() {
unsigned i = random()%m_rm_table.m_to_refine.size();
unsigned ii = i;
do {
unsigned rm_i = m_rm_table.m_to_refine[i];
monotonicity_lemma(m_rm_table.rms()[rm_i].orig_index());
if (done()) return;
i++;
if (i == m_rm_table.m_to_refine.size())
i = 0;
} while (i != ii);
}
#if 0
void core::monotonicity_lemma() {
auto const& vars = m_rm_table.m_to_refine
unsigned sz = vars.size();
unsigned start = random();
for (unsigned j = 0; !done() && j < sz; ++j) {
unsigned i = (start + j) % sz;
monotonicity_lemma(*m_emons.var2monomial(vars[i]));
}
}
#endif
void core::monotonicity_lemma(unsigned i_mon) {
const monomial & m = m_monomials[i_mon];
SASSERT(!check_monomial(m));
if (mon_has_zero(m))
return;
const rational prod_val = abs(product_value(m));
const rational m_val = abs(vvr(m));
if (m_val < prod_val)
monotonicity_lemma_lt(m, prod_val);
else if (m_val > prod_val)
monotonicity_lemma_gt(m, prod_val);
}
/**
@ -2239,31 +1867,6 @@ void core::add_abs_bound(lpvar v, llc cmp, rational const& bound) {
\/_i |m[i]| > |vvr(m[i])} or |m| <= |product_i vvr(m[i])|
*/
void core::monotonicity_lemma_gt(const monomial& m, const rational& prod_val) {
add_empty_lemma();
for (lpvar j : m) {
add_abs_bound(j, llc::GT);
}
lpvar m_j = m.var();
add_abs_bound(m_j, llc::LE, prod_val);
TRACE("nla_solver", print_lemma(tout););
}
/** \brief enforce the inequality |m| >= product |m[i]| .
/\_i |m[i]| >= |vvr(m[i])| => |m| >= |product_i vvr(m[i])|
<=>
\/_i |m[i]| < |vvr(m[i])} or |m| >= |product_i vvr(m[i])|
*/
void core::monotonicity_lemma_lt(const monomial& m, const rational& prod_val) {
add_empty_lemma();
for (lpvar j : m) {
add_abs_bound(j, llc::LT);
}
lpvar m_j = m.var();
add_abs_bound(m_j, llc::GE, prod_val);
TRACE("nla_solver", print_lemma(tout););
}
bool core:: find_bfc_to_refine_on_rmonomial(const rooted_mon& rm, bfc & bf) {
for (auto factorization : factorization_factory_imp(rm, *this)) {
@ -2550,8 +2153,8 @@ lbool core:: inner_check(bool derived) {
if (search_level == 1) {
m_order.order_lemma();
} else { // search_level == 2
monotonicity_lemma();
tangent_lemma();
m_monotone. monotonicity_lemma();
m_tangents.tangent_lemma();
}
}
return m_lemma_vec->empty()? l_undef : l_false;

27
src/util/lp/nla_core.h
View file

@ -25,6 +25,7 @@
#include "util/lp/nla_tangent_lemmas.h"
#include "util/lp/nla_basics_lemmas.h"
#include "util/lp/nla_order_lemmas.h"
#include "util/lp/nla_monotone_lemmas.h"
namespace nla {
template <typename A, typename B>
@ -92,6 +93,7 @@ struct core {
tangents m_tangents;
basics m_basics;
order m_order;
monotone m_monotone;
// methods
core(lp::lar_solver& s);
@ -195,8 +197,6 @@ struct core {
const rooted_mon& bc,
const factor& b,
std::ostream& out);
void print_monotone_array(const vector<std::pair<std::vector<rational>, unsigned>>& lex_sorted,
std::ostream& out) const;
@ -286,9 +286,6 @@ struct core {
bool has_zero_factor(const factorization& factorization) const;
template <typename T>
bool has_zero(const T& product) const;
template <typename T>
bool mon_has_zero(const T& product) const;
void init_rm_to_refine();
@ -339,31 +336,11 @@ struct core {
std::unordered_set<lpvar> collect_vars(const lemma& l) const;
bool rm_check(const rooted_mon&) const;
std::vector<rational> get_sorted_key(const rooted_mon& rm) const;
std::unordered_map<unsigned, unsigned_vector> get_rm_by_arity();
bool uniform_le(const std::vector<rational>& a,
const std::vector<rational>& b,
unsigned & strict_i) const;
vector<std::pair<rational, lpvar>> get_sorted_key_with_vars(const rooted_mon& a) const;
void negate_abs_a_le_abs_b(lpvar a, lpvar b, bool strict);
void negate_abs_a_lt_abs_b(lpvar a, lpvar b);
void assert_abs_val_a_le_abs_var_b(const rooted_mon& a, const rooted_mon& b, bool strict);
void generate_monl_strict(const rooted_mon& a, const rooted_mon& b, unsigned strict);
void generate_monl(const rooted_mon& a, const rooted_mon& b);
bool monotonicity_lemma_on_lex_sorted_rm_upper(const vector<std::pair<std::vector<rational>, unsigned>>& lex_sorted, unsigned i, const rooted_mon& rm);
bool monotonicity_lemma_on_lex_sorted_rm_lower(const vector<std::pair<std::vector<rational>, unsigned>>& lex_sorted, unsigned i, const rooted_mon& rm);
bool monotonicity_lemma_on_lex_sorted_rm(const vector<std::pair<std::vector<rational>, unsigned>>& lex_sorted, unsigned i, const rooted_mon& rm);
bool monotonicity_lemma_on_lex_sorted(const vector<std::pair<std::vector<rational>, unsigned>>& lex_sorted);
bool monotonicity_lemma_on_rms_of_same_arity(const unsigned_vector& rms);
void monotonicity_lemma();
void monotonicity_lemma(unsigned i_mon);
void add_abs_bound(lpvar v, llc cmp);
void add_abs_bound(lpvar v, llc cmp, rational const& bound);
void monotonicity_lemma_gt(const monomial& m, const rational& prod_val);
void monotonicity_lemma_lt(const monomial& m, const rational& prod_val);
bool find_bfc_to_refine_on_rmonomial(const rooted_mon& rm, bfc & bf);
bool find_bfc_to_refine(bfc& bf, lpvar &j, rational& sign, const rooted_mon*& rm_found);

299
src/util/lp/nla_monotone_lemmas.cpp Normal file
View file

@ -0,0 +1,299 @@
/*++
Copyright (c) 2017 Microsoft Corporation
Module Name:
<name>
Abstract:
<abstract>
Author:
Nikolaj Bjorner (nbjorner)
Lev Nachmanson (levnach)
Revision History:
--*/
#include "util/lp/nla_basics_lemmas.h"
#include "util/lp/nla_core.h"
#include "util/lp/factorization_factory_imp.h"
namespace nla {
monotone::monotone(core * c) : common(c) {}
void monotone::print_monotone_array(const vector<std::pair<std::vector<rational>, unsigned>>& lex_sorted,
std::ostream& out) const {
out << "Monotone array :\n";
for (const auto & t : lex_sorted ){
out << "(";
print_vector(t.first, out);
out << "), rm[" << t.second << "]" << std::endl;
}
out << "}";
}
bool monotone::monotonicity_lemma_on_lex_sorted_rm_upper(const vector<std::pair<std::vector<rational>, unsigned>>& lex_sorted, unsigned i, const rooted_mon& rm) {
const rational v = abs(vvr(rm));
const auto& key = lex_sorted[i].first;
TRACE("nla_solver", tout << "rm = ";
print_rooted_monomial_with_vars(rm, tout); tout << "i = " << i << std::endl;);
for (unsigned k = i + 1; k < lex_sorted.size(); k++) {
const auto& p = lex_sorted[k];
const rooted_mon& rmk = c().m_rm_table.rms()[p.second];
const rational vk = abs(vvr(rmk));
TRACE("nla_solver", tout << "rmk = ";
print_rooted_monomial_with_vars(rmk, tout);
tout << "\n";
tout << "vk = " << vk << std::endl;);
if (vk > v) continue;
unsigned strict;
if (uniform_le(key, p.first, strict)) {
if (static_cast<int>(strict) != -1 && !has_zero(key)) {
generate_monl_strict(rm, rmk, strict);
return true;
} else {
if (vk < v) {
generate_monl(rm, rmk);
return true;
}
}
}
}
return false;
}
bool monotone::monotonicity_lemma_on_lex_sorted_rm_lower(const vector<std::pair<std::vector<rational>, unsigned>>& lex_sorted, unsigned i, const rooted_mon& rm) {
const rational v = abs(vvr(rm));
const auto& key = lex_sorted[i].first;
TRACE("nla_solver", tout << "rm = ";
print_rooted_monomial_with_vars(rm, tout); tout << "i = " << i << std::endl;);
for (unsigned k = i; k-- > 0;) {
const auto& p = lex_sorted[k];
const rooted_mon& rmk = c().m_rm_table.rms()[p.second];
const rational vk = abs(vvr(rmk));
TRACE("nla_solver", tout << "rmk = ";
print_rooted_monomial_with_vars(rmk, tout);
tout << "\n";
tout << "vk = " << vk << std::endl;);
if (vk < v) continue;
unsigned strict;
if (uniform_le(p.first, key, strict)) {
TRACE("nla_solver", tout << "strict = " << strict << std::endl;);
if (static_cast<int>(strict) != -1) {
generate_monl_strict(rmk, rm, strict);
return true;
} else {
SASSERT(key == p.first);
if (vk < v) {
generate_monl(rmk, rm);
return true;
}
}
}
}
return false;
}
bool monotone::monotonicity_lemma_on_lex_sorted_rm(const vector<std::pair<std::vector<rational>, unsigned>>& lex_sorted, unsigned i, const rooted_mon& rm) {
return monotonicity_lemma_on_lex_sorted_rm_upper(lex_sorted, i, rm)
|| monotonicity_lemma_on_lex_sorted_rm_lower(lex_sorted, i, rm);
}
bool monotone::monotonicity_lemma_on_lex_sorted(const vector<std::pair<std::vector<rational>, unsigned>>& lex_sorted) {
for (unsigned i = 0; i < lex_sorted.size(); i++) {
unsigned rmi = lex_sorted[i].second;
const rooted_mon& rm = c().m_rm_table.rms()[rmi];
TRACE("nla_solver", print_rooted_monomial(rm, tout); tout << "\n, rm_check = " << c().rm_check(rm); tout << std::endl;);
if ((!c().rm_check(rm)) && monotonicity_lemma_on_lex_sorted_rm(lex_sorted, i, rm))
return true;
}
return false;
}
vector<std::pair<rational, lpvar>> monotone::get_sorted_key_with_vars(const rooted_mon& a) const {
vector<std::pair<rational, lpvar>> r;
for (lpvar j : a.vars()) {
r.push_back(std::make_pair(abs(vvr(j)), j));
}
std::sort(r.begin(), r.end(), [](const std::pair<rational, lpvar>& a,
const std::pair<rational, lpvar>& b) {
return
a.first < b.first ||
(a.first == b.first &&
a.second < b.second);
});
return r;
}
void monotone::negate_abs_a_le_abs_b(lpvar a, lpvar b, bool strict) {
rational av = vvr(a);
rational as = rational(nla::rat_sign(av));
rational bv = vvr(b);
rational bs = rational(nla::rat_sign(bv));
TRACE("nla_solver", tout << "av = " << av << ", bv = " << bv << "\n";);
SASSERT(as*av <= bs*bv);
llc mod_s = strict? (llc::LE): (llc::LT);
mk_ineq(as, a, mod_s); // |a| <= 0 || |a| < 0
if (a != b) {
mk_ineq(bs, b, mod_s); // |b| <= 0 || |b| < 0
mk_ineq(as, a, -bs, b, llc::GT); // negate |aj| <= |bj|
}
}
// strict version
void monotone::generate_monl_strict(const rooted_mon& a,
const rooted_mon& b,
unsigned strict) {
add_empty_lemma();
auto akey = get_sorted_key_with_vars(a);
auto bkey = get_sorted_key_with_vars(b);
SASSERT(akey.size() == bkey.size());
for (unsigned i = 0; i < akey.size(); i++) {
if (i != strict) {
negate_abs_a_le_abs_b(akey[i].second, bkey[i].second, true);
} else {
mk_ineq(b[i], llc::EQ);
negate_abs_a_lt_abs_b(akey[i].second, bkey[i].second);
}
}
assert_abs_val_a_le_abs_var_b(a, b, true);
explain(a);
explain(b);
TRACE("nla_solver", print_lemma(tout););
}
void monotone::assert_abs_val_a_le_abs_var_b(
const rooted_mon& a,
const rooted_mon& b,
bool strict) {
lpvar aj = var(a);
lpvar bj = var(b);
rational av = vvr(aj);
rational as = rational(nla::rat_sign(av));
rational bv = vvr(bj);
rational bs = rational(nla::rat_sign(bv));
// TRACE("nla_solver", tout << "rmv = " << rmv << ", jv = " << jv << "\n";);
mk_ineq(as, aj, llc::LT); // |aj| < 0
mk_ineq(bs, bj, llc::LT); // |bj| < 0
mk_ineq(as, aj, -bs, bj, strict? llc::LT : llc::LE); // |aj| < |bj|
}
void monotone::negate_abs_a_lt_abs_b(lpvar a, lpvar b) {
rational av = vvr(a);
rational as = rational(nla::rat_sign(av));
rational bv = vvr(b);
rational bs = rational(nla::rat_sign(bv));
TRACE("nla_solver", tout << "av = " << av << ", bv = " << bv << "\n";);
SASSERT(as*av < bs*bv);
mk_ineq(as, a, llc::LT); // |aj| < 0
mk_ineq(bs, b, llc::LT); // |bj| < 0
mk_ineq(as, a, -bs, b, llc::GE); // negate |aj| < |bj|
}
// not a strict version
void monotone::generate_monl(const rooted_mon& a,
const rooted_mon& b) {
TRACE("nla_solver", tout <<
"a = "; print_rooted_monomial_with_vars(a, tout) << "\n:";
tout << "b = "; print_rooted_monomial_with_vars(a, tout) << "\n:";);
add_empty_lemma();
auto akey = get_sorted_key_with_vars(a);
auto bkey = get_sorted_key_with_vars(b);
SASSERT(akey.size() == bkey.size());
for (unsigned i = 0; i < akey.size(); i++) {
negate_abs_a_le_abs_b(akey[i].second, bkey[i].second, false);
}
assert_abs_val_a_le_abs_var_b(a, b, false);
explain(a);
explain(b);
TRACE("nla_solver", print_lemma(tout););
}
std::vector<rational> monotone::get_sorted_key(const rooted_mon& rm) const {
std::vector<rational> r;
for (unsigned j : rm.vars()) {
r.push_back(abs(vvr(j)));
}
std::sort(r.begin(), r.end());
return r;
}
bool monotone::monotonicity_lemma_on_rms_of_same_arity(const unsigned_vector& rms) {
vector<std::pair<std::vector<rational>, unsigned>> lex_sorted;
for (unsigned i : rms) {
lex_sorted.push_back(std::make_pair(get_sorted_key(c().m_rm_table.rms()[i]), i));
}
std::sort(lex_sorted.begin(), lex_sorted.end(),
[](const std::pair<std::vector<rational>, unsigned> &a,
const std::pair<std::vector<rational>, unsigned> &b) {
return a.first < b.first;
});
TRACE("nla_solver", print_monotone_array(lex_sorted, tout););
return monotonicity_lemma_on_lex_sorted(lex_sorted);
}
void monotone::monotonicity_lemma() {
unsigned shift = random();
unsigned size = c().m_rm_table.m_to_refine.size();
for(unsigned i = 0; i < size && !done(); i++) {
unsigned rm_i = c().m_rm_table.m_to_refine[(i + shift)% size];
monotonicity_lemma(c().m_rm_table.rms()[rm_i].orig_index());
}
}
#if 0
void monotone::monotonicity_lemma() {
auto const& vars = m_rm_table.m_to_refine
unsigned sz = vars.size();
unsigned start = random();
for (unsigned j = 0; !done() && j < sz; ++j) {
unsigned i = (start + j) % sz;
monotonicity_lemma(*m_emons.var2monomial(vars[i]));
}
}
#endif
void monotone::monotonicity_lemma(unsigned i_mon) {
const monomial & m = c().m_monomials[i_mon];
SASSERT(!check_monomial(m));
if (c().mon_has_zero(m))
return;
const rational prod_val = abs(c().product_value(m));
const rational m_val = abs(vvr(m));
if (m_val < prod_val)
monotonicity_lemma_lt(m, prod_val);
else if (m_val > prod_val)
monotonicity_lemma_gt(m, prod_val);
}
void monotone::monotonicity_lemma_gt(const monomial& m, const rational& prod_val) {
add_empty_lemma();
for (lpvar j : m) {
c().add_abs_bound(j, llc::GT);
}
lpvar m_j = m.var();
c().add_abs_bound(m_j, llc::LE, prod_val);
TRACE("nla_solver", print_lemma(tout););
}
/** \brief enforce the inequality |m| >= product |m[i]| .
/\_i |m[i]| >= |vvr(m[i])| => |m| >= |product_i vvr(m[i])|
<=>
\/_i |m[i]| < |vvr(m[i])} or |m| >= |product_i vvr(m[i])|
*/
void monotone::monotonicity_lemma_lt(const monomial& m, const rational& prod_val) {
add_empty_lemma();
for (lpvar j : m) {
c().add_abs_bound(j, llc::LT);
}
lpvar m_j = m.var();
c().add_abs_bound(m_j, llc::GE, prod_val);
TRACE("nla_solver", print_lemma(tout););
}
}

44
src/util/lp/nla_monotone_lemmas.h Normal file
View file

@ -0,0 +1,44 @@
/*++
Copyright (c) 2017 Microsoft Corporation
Module Name:
<name>
Abstract:
<abstract>
Author:
Nikolaj Bjorner (nbjorner)
Lev Nachmanson (levnach)
Revision History:
--*/
#pragma once
namespace nla {
struct core;
struct monotone: common {
monotone(core *core);
void print_monotone_array(const vector<std::pair<std::vector<rational>, unsigned>>& lex_sorted,
std::ostream& out) const;
bool monotonicity_lemma_on_lex_sorted_rm_upper(const vector<std::pair<std::vector<rational>, unsigned>>& lex_sorted, unsigned i, const rooted_mon& rm);
bool monotonicity_lemma_on_lex_sorted_rm_lower(const vector<std::pair<std::vector<rational>, unsigned>>& lex_sorted, unsigned i, const rooted_mon& rm);
bool monotonicity_lemma_on_lex_sorted_rm(const vector<std::pair<std::vector<rational>, unsigned>>& lex_sorted, unsigned i, const rooted_mon& rm);
bool monotonicity_lemma_on_lex_sorted(const vector<std::pair<std::vector<rational>, unsigned>>& lex_sorted);
bool monotonicity_lemma_on_rms_of_same_arity(const unsigned_vector& rms);
void monotonicity_lemma();
void monotonicity_lemma(unsigned i_mon);
void monotonicity_lemma_gt(const monomial& m, const rational& prod_val);
void monotonicity_lemma_lt(const monomial& m, const rational& prod_val);
void generate_monl_strict(const rooted_mon& a, const rooted_mon& b, unsigned strict);
void generate_monl(const rooted_mon& a, const rooted_mon& b);
std::vector<rational> get_sorted_key(const rooted_mon& rm) const;
vector<std::pair<rational, lpvar>> get_sorted_key_with_vars(const rooted_mon& a) const;
void negate_abs_a_le_abs_b(lpvar a, lpvar b, bool strict);
void negate_abs_a_lt_abs_b(lpvar a, lpvar b);
void assert_abs_val_a_le_abs_var_b(const rooted_mon& a, const rooted_mon& b, bool strict);
};
}