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wip - local search

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This commit is contained in:
Nikolaj Bjorner 2023-02-15 08:36:10 -08:00
parent 8ce0c56ff5
commit 4f20b8e2ba
2 changed files with 114 additions and 40 deletions
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105
src/sat/sat_ddfw.cpp
View file

@ -9,7 +9,7 @@
DDFW Local search module for clauses
Author:
Author:
Nikolaj Bjorner, Marijn Heule 2019-4-23
@ -33,27 +33,45 @@
namespace sat {
ddfw::~ddfw() {
for (auto& ci : m_clauses) {
m_alloc.del_clause(ci.m_clause);
}
for (auto& ci : m_clauses)
m_alloc.del_clause(ci.m_clause);
}
lbool ddfw::check(unsigned sz, literal const* assumptions, parallel* p) {
init(sz, assumptions);
flet<parallel*> _p(m_par, p);
while (m_limit.inc() && m_min_sz > 0) {
if (should_reinit_weights()) do_reinit_weights();
else if (do_flip()) ;
else if (should_restart()) do_restart();
else if (should_parallel_sync()) do_parallel_sync();
else shift_weights();
}
if (m_plugin)
check_with_plugin();
else
check_without_plugin();
remove_assumptions();
log();
return m_min_sz == 0 ? l_true : l_undef;
}
void ddfw::check_without_plugin() {
while (m_limit.inc() && m_min_sz > 0) {
if (should_reinit_weights()) do_reinit_weights();
else if (do_flip<false>());
else if (should_restart()) do_restart();
else if (should_parallel_sync()) do_parallel_sync();
else shift_weights();
}
}
void ddfw::check_with_plugin() {
m_plugin->init_search();
while (m_limit.inc() && m_min_sz > 0) {
if (should_reinit_weights()) do_reinit_weights();
else if (do_flip<true>());
else if (do_literal_flip<true>());
else if (should_restart()) do_restart(), m_plugin->on_restart();
else if (should_parallel_sync()) do_parallel_sync();
else shift_weights(), m_plugin->on_rescale();
}
m_plugin->finish_search();
}
void ddfw::log() {
double sec = m_stopwatch.get_current_seconds();
double kflips_per_sec = (m_flips - m_last_flips) / (1000.0 * sec);
@ -77,55 +95,72 @@ namespace sat {
m_last_flips = m_flips;
}
template<bool uses_plugin>
bool ddfw::do_flip() {
bool_var v = pick_var();
bool_var v = pick_var<uses_plugin>();
return apply_flip<uses_plugin>(v);
}
template<bool uses_plugin>
bool ddfw::apply_flip(bool_var v) {
if (v == null_bool_var)
return false;
if (reward(v) > 0 || (reward(v) == 0 && m_rand(100) <= m_config.m_use_reward_zero_pct)) {
flip(v);
if (m_unsat.size() <= m_min_sz) save_best_values();
if (uses_plugin)
m_plugin->flip(v);
else
flip(v);
if (m_unsat.size() <= m_min_sz)
save_best_values();
return true;
}
return false;
}
template<bool uses_plugin>
bool_var ddfw::pick_var() {
double sum_pos = 0;
unsigned n = 1;
double r;
bool_var v0 = null_bool_var;
for (bool_var v : m_unsat_vars) {
double r = reward(v);
if (r > 0.0) {
sum_pos += score(r);
}
else if (r == 0.0 && sum_pos == 0 && (m_rand() % (n++)) == 0) {
v0 = v;
}
r = uses_plugin ? plugin_reward(v) : reward(v);
if (r > 0.0)
sum_pos += score(r);
else if (r == 0.0 && sum_pos == 0 && (m_rand() % (n++)) == 0)
v0 = v;
}
if (sum_pos > 0) {
double lim_pos = ((double) m_rand() / (1.0 + m_rand.max_value())) * sum_pos;
for (bool_var v : m_unsat_vars) {
double r = reward(v);
r = uses_plugin ? plugin_reward(v) : reward(v);
if (r > 0) {
lim_pos -= score(r);
if (lim_pos <= 0) {
return v;
}
if (lim_pos <= 0)
return v;
}
}
}
if (v0 != null_bool_var) {
if (v0 != null_bool_var)
return v0;
}
if (m_unsat_vars.empty())
return 0;
return m_unsat_vars.elem_at(m_rand(m_unsat_vars.size()));
}
/**
* TBD: map reward value to a score, possibly through an exponential function, such as
* exp(-tau/r), where tau > 0
*/
double ddfw::mk_score(double r) {
return r;
template<bool uses_plugin>
bool ddfw::do_literal_flip() {
return apply_flip<uses_plugin>(pick_literal_var<uses_plugin>());
}
/*
* Pick a random false literal from a satisfied clause such that
* the literal has zero break count and positive reward.
*/
template<bool uses_plugin>
bool_var ddfw::pick_literal_var() {
return null_bool_var;
}
void ddfw::add(unsigned n, literal const* c) {
clause* cls = m_alloc.mk_clause(n, c, false);
@ -409,6 +444,8 @@ namespace sat {
for (unsigned i = 0; i < num_vars(); ++i)
m_model[i] = to_lbool(value(i));
save_priorities();
if (m_plugin)
m_plugin->on_save_model();
}

49
src/sat/sat_ddfw.h
View file

@ -31,6 +31,17 @@ namespace sat {
class solver;
class parallel;
class local_search_plugin {
public:
virtual void init_search() = 0;
virtual void finish_search() = 0;
virtual void flip(bool_var v) = 0;
virtual double reward(bool_var v) = 0;
virtual void on_rescale() = 0;
virtual void on_save_model() = 0;
virtual void on_restart() = 0;
};
class ddfw : public i_local_search {
public:
struct clause_info {
@ -83,6 +94,7 @@ namespace sat {
double m_reward = 0;
unsigned m_make_count = 0;
int m_bias = 0;
bool m_external = false;
ema m_reward_avg = 1e-5;
};
@ -113,14 +125,15 @@ namespace sat {
stopwatch m_stopwatch;
parallel* m_par;
scoped_ptr< local_search_plugin> m_plugin;
void flatten_use_list();
double mk_score(double r);
inline double score(double r) { return r; } // TBD: { for (unsigned sz = m_scores.size(); sz <= r; ++sz) m_scores.push_back(mk_score(sz)); return m_scores[r]; }
/**
* TBD: map reward value to a score, possibly through an exponential function, such as
* exp(-tau/r), where tau > 0
*/
inline double score(double r) { return r; }
inline unsigned num_vars() const { return m_vars.size(); }
@ -134,6 +147,12 @@ namespace sat {
inline double reward(bool_var v) const { return m_vars[v].m_reward; }
inline double plugin_reward(bool_var v) const { return m_plugin->reward(v); }
void set_external(bool_var v) { m_vars[v].m_external = true; }
inline bool is_external(bool_var v) const { return m_vars[v].m_external; }
inline int& bias(bool_var v) { return m_vars[v].m_bias; }
unsigned value_hash() const;
@ -164,9 +183,25 @@ namespace sat {
inline void dec_reward(literal lit, double w) { reward(lit.var()) -= w; }
void check_with_plugin();
void check_without_plugin();
// flip activity
template<bool uses_plugin>
bool do_flip();
bool_var pick_var();
template<bool uses_plugin>
bool_var pick_var();
template<bool uses_plugin>
bool apply_flip(bool_var v);
template<bool uses_plugin>
bool do_literal_flip();
template<bool uses_plugin>
bool_var pick_literal_var();
void save_best_values();
void save_model();
void save_priorities();
@ -215,6 +250,8 @@ namespace sat {
~ddfw() override;
void set(local_search_plugin* p) { m_plugin = p; }
lbool check(unsigned sz, literal const* assumptions, parallel* p) override;
void updt_params(params_ref const& p) override;