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z3-z3-4.12.6.src.sat.smt.euf_relevancy.cpp Maven / Gradle / Ivy
/*++
Copyright (c) 2020 Microsoft Corporation
Module Name:
smt_relevant.cpp
Abstract:
Relevancy propagation
Author:
Nikolaj Bjorner (nbjorner) 2021-12-27
--*/
#include "sat/sat_solver.h"
#include "sat/smt/euf_solver.h"
#include "sat/smt/euf_relevancy.h"
namespace euf {
void relevancy::pop(unsigned n) {
if (!m_enabled)
return;
if (n <= m_num_scopes) {
m_num_scopes -= n;
return;
}
else if (m_num_scopes > 0) {
n -= m_num_scopes;
m_num_scopes = 0;
}
SASSERT(n > 0);
unsigned sz = m_lim[m_lim.size() - n];
for (unsigned i = m_trail.size(); i-- > sz; ) {
auto const& [u, idx] = m_trail[i];
switch (u) {
case update::relevant_var:
m_relevant_var_ids[idx] = false;
break;
case update::add_queue:
m_queue.pop_back();
break;
case update::add_clause: {
sat::clause* c = m_clauses.back();
for (sat::literal lit : *c) {
SASSERT(m_occurs[lit.index()].back() == m_clauses.size() - 1);
m_occurs[lit.index()].pop_back();
}
m_clauses.pop_back();
m_roots.pop_back();
m_alloc.del_clause(c);
break;
}
case update::set_root:
m_roots[idx] = false;
break;
case update::set_qhead:
m_qhead = idx;
break;
default:
UNREACHABLE();
break;
}
}
m_trail.shrink(sz);
m_lim.shrink(m_lim.size() - n);
}
void relevancy::add_root(unsigned n, sat::literal const* lits) {
if (!m_enabled)
return;
flush();
TRACE("relevancy", tout << "root " << sat::literal_vector(n, lits) << "\n");
sat::literal true_lit = sat::null_literal;
for (unsigned i = 0; i < n; ++i) {
if (ctx.s().value(lits[i]) == l_true) {
if (is_relevant(lits[i]))
return;
true_lit = lits[i];
}
}
if (true_lit != sat::null_literal) {
mark_relevant(true_lit);
return;
}
sat::clause* cl = m_alloc.mk_clause(n, lits, false);
unsigned sz = m_clauses.size();
m_clauses.push_back(cl);
m_roots.push_back(true);
m_trail.push_back(std::make_pair(update::add_clause, 0));
for (sat::literal lit : *cl) {
ctx.s().set_external(lit.var());
occurs(lit).push_back(sz);
}
}
void relevancy::add_def(unsigned n, sat::literal const* lits) {
if (!m_enabled)
return;
flush();
TRACE("relevancy", tout << "def " << sat::literal_vector(n, lits) << "\n");
for (unsigned i = 0; i < n; ++i) {
if (ctx.s().value(lits[i]) == l_false && is_relevant(lits[i])) {
add_root(n, lits);
return;
}
}
sat::clause* cl = m_alloc.mk_clause(n, lits, false);
unsigned sz = m_clauses.size();
m_clauses.push_back(cl);
m_roots.push_back(false);
m_trail.push_back(std::make_pair(update::add_clause, 0));
for (sat::literal lit : *cl) {
ctx.s().set_external(lit.var());
occurs(lit).push_back(sz);
}
}
void relevancy::add_to_propagation_queue(sat::literal lit) {
m_trail.push_back(std::make_pair(update::add_queue, lit.var()));
m_queue.push_back(std::make_pair(lit, nullptr));
}
void relevancy::set_relevant(sat::literal lit) {
euf::enode* n = ctx.bool_var2enode(lit.var());
if (n)
mark_relevant(n);
m_relevant_var_ids.setx(lit.var(), true, false);
m_trail.push_back(std::make_pair(update::relevant_var, lit.var()));
}
void relevancy::set_asserted(sat::literal lit) {
SASSERT(!is_relevant(lit));
SASSERT(ctx.s().value(lit) == l_true);
set_relevant(lit);
add_to_propagation_queue(lit);
ctx.asserted(lit);
}
/**
* Boolean variable is set relevant because an E-node is relevant.
*
*/
void relevancy::relevant_eh(sat::bool_var v) {
if (is_relevant(v))
return;
sat::literal lit(v);
switch (ctx.s().value(lit)) {
case l_undef:
set_relevant(lit);
break;
case l_true:
set_asserted(lit);
break;
case l_false:
set_asserted(~lit);
break;
}
}
void relevancy::asserted(sat::literal lit) {
TRACE("relevancy", tout << "asserted " << lit << " relevant " << is_relevant(lit) << "\n");
if (!m_enabled)
return;
flush();
if (is_relevant(lit)) {
add_to_propagation_queue(lit);
return;
}
if (ctx.s().lvl(lit) <= ctx.s().search_lvl()) {
set_relevant(lit);
add_to_propagation_queue(lit);
return;
}
for (auto idx : occurs(lit)) {
if (!m_roots[idx])
continue;
for (sat::literal lit2 : *m_clauses[idx])
if (lit2 != lit && ctx.s().value(lit2) == l_true && is_relevant(lit2))
goto next;
set_relevant(lit);
add_to_propagation_queue(lit);
return;
next:
;
}
}
void relevancy::propagate() {
if (!m_enabled)
return;
flush();
if (m_qhead == m_queue.size())
return;
m_trail.push_back(std::make_pair(update::set_qhead, m_qhead));
while (m_qhead < m_queue.size() && !ctx.s().inconsistent() && ctx.get_manager().inc()) {
auto const& [lit, n] = m_queue[m_qhead++];
SASSERT(n || lit != sat::null_literal);
SASSERT(!n || lit == sat::null_literal);
if (n)
propagate_relevant(n);
else
propagate_relevant(lit);
}
}
void relevancy::merge(euf::enode* root, euf::enode* other) {
TRACE("relevancy", tout << "merge #" << ctx.bpp(root) << " " << is_relevant(root) << " #" << ctx.bpp(other) << " " << is_relevant(other) << "\n");
if (is_relevant(root))
mark_relevant(other);
else if (is_relevant(other))
mark_relevant(root);
}
void relevancy::mark_relevant(euf::enode* n) {
if (!m_enabled)
return;
flush();
if (is_relevant(n))
return;
TRACE("relevancy", tout << "mark #" << ctx.bpp(n) << "\n");
m_trail.push_back(std::make_pair(update::add_queue, 0));
m_queue.push_back(std::make_pair(sat::null_literal, n));
}
void relevancy::mark_relevant(sat::literal lit) {
TRACE("relevancy", tout << "mark " << lit << " " << is_relevant(lit) << " " << ctx.s().value(lit) << " lim: " << m_lim.size() << "\n");
if (!m_enabled)
return;
flush();
if (is_relevant(lit))
return;
set_relevant(lit);
switch (ctx.s().value(lit)) {
case l_true:
break;
case l_false:
lit.neg();
break;
default:
return;
}
add_to_propagation_queue(lit);
}
void relevancy::propagate_relevant(sat::literal lit) {
SASSERT(m_num_scopes == 0);
TRACE("relevancy", tout << "propagate " << lit << " lim: " << m_lim.size() << "\n");
SASSERT(ctx.s().value(lit) == l_true);
SASSERT(is_relevant(lit));
euf::enode* n = ctx.bool_var2enode(lit.var());
if (n && !ctx.get_si().is_bool_op(n->get_expr()))
return;
for (auto idx : occurs(~lit)) {
if (m_roots[idx])
continue;
sat::clause* cl = m_clauses[idx];
sat::literal true_lit = sat::null_literal;
for (sat::literal lit2 : *cl) {
if (ctx.s().value(lit2) == l_true) {
if (is_relevant(lit2))
goto next;
true_lit = lit2;
}
}
if (true_lit != sat::null_literal)
set_asserted(true_lit);
else {
m_trail.push_back(std::make_pair(update::set_root, idx));
m_roots[idx] = true;
}
next:
TRACE("relevancy", tout << "propagate " << lit << " " << true_lit << " " << m_roots[idx] << "\n");
;
}
}
void relevancy::propagate_relevant(euf::enode* n) {
m_todo.push_back(n);
while (!m_todo.empty()) {
n = m_todo.back();
m_todo.pop_back();
TRACE("relevancy", tout << "propagate #" << ctx.bpp(n) << " lim: " << m_lim.size() << "\n");
if (n->is_relevant())
continue;
m_stack.push_back(n);
while (!m_stack.empty()) {
n = m_stack.back();
unsigned sz = m_stack.size();
bool is_bool_op = ctx.get_si().is_bool_op(n->get_expr());
if (!is_bool_op)
for (euf::enode* arg : euf::enode_args(n))
if (!arg->is_relevant())
m_stack.push_back(arg);
if (sz != m_stack.size())
continue;
if (!n->is_relevant()) {
ctx.get_egraph().set_relevant(n);
ctx.relevant_eh(n);
sat::bool_var v = n->bool_var();
if (v != sat::null_bool_var)
relevant_eh(v);
for (euf::enode* sib : euf::enode_class(n))
if (!sib->is_relevant())
m_todo.push_back(sib);
}
if (!ctx.get_manager().inc()) {
m_todo.reset();
m_stack.reset();
return;
}
m_stack.pop_back();
}
}
}
void relevancy::set_enabled(bool e) {
m_enabled = e;
ctx.get_egraph().set_default_relevant(!e);
}
}
