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https://github.com/Z3Prover/z3
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104 lines
3.2 KiB
C++
104 lines
3.2 KiB
C++
/*++
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Copyright (c) 2021 Microsoft Corporation
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Module Name:
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polysat clause builder
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Author:
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Jakob Rath 2021-04-6
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--*/
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#include "math/polysat/clause_builder.h"
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#include "math/polysat/solver.h"
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#include "math/polysat/log.h"
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namespace polysat {
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static_assert(!std::is_copy_assignable_v<clause_builder>);
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static_assert(!std::is_copy_constructible_v<clause_builder>);
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static_assert(std::is_move_assignable_v<clause_builder>);
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static_assert(std::is_move_constructible_v<clause_builder>);
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clause_builder::clause_builder(solver& s, char const* name):
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m_solver(&s), m_name(name)
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{}
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void clause_builder::reset() {
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m_literals.reset();
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m_is_tautology = false;
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m_redundant = clause::redundant_default;
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m_name = "";
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SASSERT(empty());
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}
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clause_ref clause_builder::build() {
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if (m_is_tautology) {
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verbose_stream() << "Tautology: " << m_literals << " (" << (m_name ? m_name : "<null>") << ")\n";
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for (sat::literal lit : m_literals)
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verbose_stream() << " " << lit_pp(*m_solver, lit) << "\n";
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reset();
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return nullptr;
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}
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std::sort(m_literals.data(), m_literals.data() + m_literals.size());
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sat::literal prev = sat::null_literal;
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unsigned j = 0;
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for (unsigned i = 0; i < m_literals.size(); ++i) {
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sat::literal lit = m_literals[i];
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if (prev == lit)
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continue;
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prev = lit;
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m_literals[j++] = lit;
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}
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m_literals.shrink(j);
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clause_ref cl = clause::from_literals(std::move(m_literals));
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SASSERT(cl);
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cl->set_redundant(m_redundant);
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cl->set_name(m_name);
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m_redundant = clause::redundant_default;
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m_name = "";
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SASSERT(empty());
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return cl;
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}
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void clause_builder::insert(sat::literal lit) {
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insert(m_solver->lit2cnstr(lit));
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}
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// TODO: in the final version, we may also skip assumptions (and even literals propagated at the base level),
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// provided we correctly track external dependencies/level for the clause.
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void clause_builder::insert(signed_constraint c) {
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SASSERT(c);
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if (c.is_always_false()) // filter out trivial constraints such as "4 < 2"
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return;
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if (c.is_always_true()) {
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IF_VERBOSE(10, verbose_stream() << "Clause is tautology because of " << lit_pp(s(), c) << "\n");
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m_is_tautology = true;
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return;
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}
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m_literals.push_back(c.blit());
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}
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void clause_builder::insert_eval(sat::literal lit) {
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insert_eval(m_solver->lit2cnstr(lit));
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}
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void clause_builder::insert_eval(signed_constraint c) {
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if (c.bvalue(*m_solver) == l_undef)
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m_solver->assign_eval(~c.blit());
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insert(c);
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}
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void clause_builder::insert_try_eval(sat::literal lit) {
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insert_eval(m_solver->lit2cnstr(lit));
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}
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void clause_builder::insert_try_eval(signed_constraint c) {
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if (c.bvalue(*m_solver) == l_undef && c.is_currently_false(*m_solver))
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m_solver->assign_eval(~c.blit());
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insert(c);
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}
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}
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