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streamline pb solver interface and naming after removal of xor
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Nikolaj Bjorner
parent
13f05ae9dc
commit
026065ff71
73 changed files with 1131 additions and 1201 deletions
271
src/sat/smt/pb_card.cpp
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271
src/sat/smt/pb_card.cpp
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/*++
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Copyright (c) 2017 Microsoft Corporation
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Module Name:
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ba_card.cpp
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Abstract:
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Interface for Cardinality constraints.
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Author:
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Nikolaj Bjorner (nbjorner) 2017-01-30
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--*/
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#include "sat/smt/pb_card.h"
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#include "sat/smt/pb_solver.h"
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#include "sat/sat_simplifier.h"
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namespace pb {
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card::card(unsigned id, literal lit, literal_vector const& lits, unsigned k) :
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constraint(tag_t::card_t, id, lit, lits.size(), get_obj_size(lits.size()), k) {
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for (unsigned i = 0; i < size(); ++i) {
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m_lits[i] = lits[i];
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}
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}
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void card::negate() {
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m_lit.neg();
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for (unsigned i = 0; i < m_size; ++i) {
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m_lits[i].neg();
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}
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m_k = m_size - m_k + 1;
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SASSERT(m_size >= m_k && m_k > 0);
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}
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bool card::is_watching(literal l) const {
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unsigned sz = std::min(k() + 1, size());
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for (unsigned i = 0; i < sz; ++i) {
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if ((*this)[i] == l) return true;
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}
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return false;
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}
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double card::get_reward(solver_interface const& s, sat::literal_occs_fun& literal_occs) const {
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unsigned k = this->k(), slack = 0;
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bool do_add = s.get_config().m_lookahead_reward == sat::heule_schur_reward;
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double to_add = do_add ? 0 : 1;
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for (literal l : *this) {
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switch (s.value(l)) {
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case l_true: --k; if (k == 0) return 0;
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case l_undef:
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if (do_add) to_add += literal_occs(l);
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++slack; break;
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case l_false: break;
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}
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}
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if (k >= slack) return 1;
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return pow(0.5, static_cast<double>(slack - k + 1)) * to_add;
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}
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std::ostream& card::display(std::ostream& out) const {
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for (literal l : *this)
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out << l << " ";
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return out << " >= " << k();
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}
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void constraint::display_lit(std::ostream& out, solver_interface const& s, literal lit, unsigned sz, bool values) const {
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if (lit != sat::null_literal) {
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if (values) {
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out << lit << "[" << sz << "]";
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out << "@(" << s.value(lit);
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if (s.value(lit) != l_undef) {
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out << ":" << s.lvl(lit);
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}
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out << "): ";
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}
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else {
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out << lit << " == ";
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}
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}
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}
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std::ostream& card::display(std::ostream& out, solver_interface const& s, bool values) const {
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auto const& c = *this;
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display_lit(out, s, c.lit(), c.size(), values);
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for (unsigned i = 0; i < c.size(); ++i) {
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literal l = c[i];
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out << l;
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if (values) {
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out << "@(" << s.value(l);
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if (s.value(l) != l_undef) {
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out << ":" << s.lvl(l);
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}
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out << ") ";
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}
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else {
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out << " ";
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}
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}
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return out << ">= " << c.k() << "\n";
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}
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void card::clear_watch(solver_interface& s) {
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if (is_clear()) return;
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reset_watch();
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unsigned sz = std::min(k() + 1, size());
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for (unsigned i = 0; i < sz; ++i)
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unwatch_literal(s, (*this)[i]);
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}
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bool card::init_watch(solver_interface& s) {
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auto& c = *this;
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literal root = c.lit();
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if (root != sat::null_literal && s.value(root) == l_false) {
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clear_watch(s);
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negate();
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root.neg();
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}
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if (root != sat::null_literal) {
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if (!is_watched(s, root)) watch_literal(s, root);
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if (!is_pure() && !is_watched(s, ~root)) watch_literal(s, ~root);
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}
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TRACE("ba", display(tout << "init watch: ", s, true););
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SASSERT(root == sat::null_literal || s.value(root) == l_true);
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unsigned j = 0, sz = c.size(), bound = c.k();
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// put the non-false literals into the head.
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if (bound == sz) {
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for (literal l : c) s.assign(c, l);
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return false;
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}
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for (unsigned i = 0; i < sz; ++i) {
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if (s.value(c[i]) != l_false) {
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if (j != i) {
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if (c.is_watched() && j <= bound && i > bound) {
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c.unwatch_literal(s, c[j]);
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c.watch_literal(s, c[i]);
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}
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c.swap(i, j);
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}
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++j;
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}
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}
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DEBUG_CODE(
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bool is_false = false;
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for (literal l : c) {
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SASSERT(!is_false || s.value(l) == l_false);
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is_false = s.value(l) == l_false;
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});
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// j is the number of non-false, sz - j the number of false.
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if (j < bound) {
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if (is_watched()) clear_watch(s);
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SASSERT(0 < bound && bound < sz);
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literal alit = c[j];
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//
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// we need the assignment level of the asserting literal to be maximal.
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// such that conflict resolution can use the asserting literal as a starting
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// point.
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//
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for (unsigned i = bound; i < sz; ++i) {
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if (s.lvl(alit) < s.lvl(c[i])) {
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c.swap(i, j);
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alit = c[j];
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}
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}
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s.set_conflict(c, alit);
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return false;
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}
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else if (j == bound) {
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for (unsigned i = 0; i < bound; ++i) {
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s.assign(c, c[i]);
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}
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return false;
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}
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else {
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if (c.is_watched()) return true;
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clear_watch(s);
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for (unsigned i = 0; i <= bound; ++i) {
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c.watch_literal(s, c[i]);
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}
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c.set_watch();
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return true;
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}
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}
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card& constraint::to_card() {
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SASSERT(is_card());
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return static_cast<card&>(*this);
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}
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card const& constraint::to_card() const {
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SASSERT(is_card());
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return static_cast<card const&>(*this);
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}
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bool card::is_extended_binary(literal_vector& r) const {
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auto const& ca = *this;
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if (ca.size() == ca.k() + 1 && ca.lit() == sat::null_literal) {
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r.reset();
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for (literal l : ca) r.push_back(l);
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return true;
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}
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else {
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return false;
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}
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}
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bool card::validate_unit_propagation(solver_interface const& s, literal alit) const {
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(void) alit;
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if (lit() != sat::null_literal && s.value(lit()) != l_true)
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return false;
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for (unsigned i = k(); i < size(); ++i)
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if (s.value((*this)[i]) != l_false)
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return false;
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return true;
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}
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lbool card::eval(solver_interface const& s) const {
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unsigned trues = 0, undefs = 0;
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for (literal l : *this) {
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switch (s.value(l)) {
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case l_true: trues++; break;
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case l_undef: undefs++; break;
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default: break;
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}
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}
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if (trues + undefs < k()) return l_false;
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if (trues >= k()) return l_true;
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return l_undef;
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}
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lbool card::eval(sat::model const& m) const {
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unsigned trues = 0, undefs = 0;
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for (literal l : *this) {
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switch (pb::value(m, l)) {
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case l_true: trues++; break;
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case l_undef: undefs++; break;
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default: break;
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}
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}
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if (trues + undefs < k()) return l_false;
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if (trues >= k()) return l_true;
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return l_undef;
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}
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void card::init_use_list(sat::ext_use_list& ul) const {
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auto idx = cindex();
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for (auto l : *this)
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ul.insert(l, idx);
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}
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bool card::is_blocked(sat::simplifier& sim, literal lit) const {
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unsigned weight = 0;
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for (literal l2 : *this)
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if (sim.is_marked(~l2)) ++weight;
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return weight >= k();
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}
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}
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