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rework sat.mus to use restart count for bounded minimization

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2017-01-26 13:28:40 -08:00
parent c3eb279637
commit 962979b09c
3 changed files with 24 additions and 39 deletions
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59
src/sat/sat_mus.cpp
View file

@ -23,7 +23,7 @@ Notes:
namespace sat {
mus::mus(solver& s):s(s), m_is_active(false),m_restart(0), m_max_restarts(0) {}
mus::mus(solver& s):s(s), m_is_active(false), m_max_num_restarts(UINT_MAX) {}
mus::~mus() {}
@ -31,8 +31,6 @@ namespace sat {
m_core.reset();
m_mus.reset();
m_model.reset();
m_max_restarts = (s.m_stats.m_restart - m_restart) + 10;
m_restart = s.m_stats.m_restart;
}
void mus::set_core() {
@ -49,12 +47,12 @@ namespace sat {
}
lbool mus::operator()() {
m_max_num_restarts = s.m_config.m_core_minimize_partial ? s.num_restarts() + 10 : UINT_MAX;
flet<bool> _disable_min(s.m_config.m_core_minimize, false);
flet<bool> _is_active(m_is_active, true);
IF_VERBOSE(3, verbose_stream() << "(sat.mus " << s.get_core() << ")\n";);
IF_VERBOSE(3, verbose_stream() << "(sat.mus size: " << s.get_core().size() << " core: [" << s.get_core() << "])\n";);
reset();
lbool r = mus1();
m_restart = s.m_stats.m_restart;
return r;
}
@ -63,13 +61,13 @@ namespace sat {
TRACE("sat", tout << "old core: " << s.get_core() << "\n";);
literal_vector& core = get_core();
literal_vector& mus = m_mus;
if (core.size() > 64) {
if (!minimize_partial && core.size() > 64) {
return mus2();
}
unsigned delta_time = 0;
unsigned core_miss = 0;
while (!core.empty()) {
IF_VERBOSE(3, verbose_stream() << "(opt.mus reducing core: " << core.size() << " mus: " << mus.size() << ")\n";);
IF_VERBOSE(1, verbose_stream() << "(sat.mus num-to-process: " << core.size() << " mus: " << mus.size();
if (minimize_partial) verbose_stream() << " max-restarts: " << m_max_num_restarts;
verbose_stream() << ")\n";);
TRACE("sat",
tout << "core: " << core << "\n";
tout << "mus: " << mus << "\n";);
@ -78,34 +76,35 @@ namespace sat {
set_core();
return l_undef;
}
if (minimize_partial && 3*delta_time > core.size() && core.size() < mus.size()) {
break;
}
unsigned num_literals = core.size() + mus.size();
if (num_literals <= 2) {
// IF_VERBOSE(0, verbose_stream() << "num literals: " << core << " " << mus << "\n";);
break;
}
if (s.m_config.m_core_minimize_partial && s.m_stats.m_restart - m_restart > m_max_restarts) {
IF_VERBOSE(1, verbose_stream() << "(sat restart budget exceeded)\n";);
set_core();
return l_true;
}
literal lit = core.back();
core.pop_back();
lbool is_sat;
{
flet<unsigned> _restart_bound(s.m_config.m_restart_max, m_max_num_restarts);
scoped_append _sa(mus, core);
mus.push_back(~lit);
is_sat = s.check(mus.size(), mus.c_ptr());
TRACE("sat", tout << "mus: " << mus << "\n";);
}
IF_VERBOSE(1, verbose_stream() << "(sat.mus " << is_sat << ")\n";);
switch (is_sat) {
case l_undef:
core.push_back(lit);
set_core();
return l_undef;
if (!s.canceled()) {
// treat restart max as sat, so literal is in the mus
mus.push_back(lit);
}
else {
core.push_back(lit);
set_core();
return l_undef;
}
break;
case l_true: {
SASSERT(value_at(lit, s.get_model()) == l_false);
mus.push_back(lit);
@ -115,11 +114,9 @@ namespace sat {
case l_false:
literal_vector const& new_core = s.get_core();
if (new_core.contains(~lit)) {
IF_VERBOSE(3, verbose_stream() << "miss core " << lit << "\n";);
++core_miss;
IF_VERBOSE(3, verbose_stream() << "(sat.mus unit reduction, literal is in both cores " << lit << ")\n";);
}
else {
core_miss = 0;
TRACE("sat", tout << "core: " << new_core << " mus: " << mus << "\n";);
core.reset();
for (unsigned i = 0; i < new_core.size(); ++i) {
@ -131,14 +128,6 @@ namespace sat {
}
break;
}
unsigned new_num_literals = core.size() + mus.size();
if (new_num_literals == num_literals) {
delta_time++;
}
else {
delta_time = 0;
}
}
set_core();
IF_VERBOSE(3, verbose_stream() << "(sat.mus.new " << s.m_core << ")\n";);
@ -159,13 +148,9 @@ namespace sat {
lbool mus::qx(literal_set& assignment, literal_set& support, bool has_support) {
lbool is_sat = l_true;
if (s.m_config.m_core_minimize_partial && s.m_stats.m_restart - m_restart > m_max_restarts) {
IF_VERBOSE(1, verbose_stream() << "(sat restart budget exceeded)\n";);
return l_true;
}
if (has_support) {
scoped_append _sa(m_mus, support.to_vector());
is_sat = s.check(m_mus.size(), m_mus.c_ptr());
is_sat = s.check(m_mus.size(), m_mus.c_ptr());
switch (is_sat) {
case l_false: {
literal_set core(s.get_core());
@ -173,7 +158,7 @@ namespace sat {
assignment.reset();
return l_true;
}
case l_undef:
case l_undef:
return l_undef;
case l_true:
update_model();

3
src/sat/sat_mus.h
View file

@ -26,8 +26,7 @@ namespace sat {
literal_vector m_mus;
bool m_is_active;
model m_model; // model obtained during minimal unsat core
unsigned m_restart;
unsigned m_max_restarts;
unsigned m_max_num_restarts;
public:

1
src/sat/sat_solver.h
View file

@ -209,6 +209,7 @@ namespace sat {
bool inconsistent() const { return m_inconsistent; }
unsigned num_vars() const { return m_level.size(); }
unsigned num_clauses() const;
unsigned num_restarts() const { return m_restarts; }
bool is_external(bool_var v) const { return m_external[v] != 0; }
bool was_eliminated(bool_var v) const { return m_eliminated[v] != 0; }
unsigned scope_lvl() const { return m_scope_lvl; }