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basic primal/dual

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2014-08-29 09:52:56 -07:00
parent 67190b2f17
commit 3da60804fc
3 changed files with 109 additions and 54 deletions
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157
src/opt/maxres.cpp
View file

@ -88,6 +88,8 @@ private:
bool m_all_cores;
bool m_add_upper_bound_block;
typedef ptr_vector<expr> exprs;
public:
maxres(context& c,
weights_t& ws, expr_ref_vector const& soft,
@ -176,8 +178,8 @@ public:
init();
init_local();
sls();
ptr_vector<expr> mcs;
vector<ptr_vector<expr> > cores;
exprs mcs;
vector<exprs> cores;
while (m_lower < m_upper) {
TRACE("opt",
display_vec(tout, m_asms.size(), m_asms.c_ptr());
@ -219,19 +221,18 @@ public:
init_local();
sls();
set_mus(false);
ptr_vector<expr> mcs;
exprs mcs;
lbool is_sat = l_true;
while (m_lower < m_upper && is_sat == l_true) {
IF_VERBOSE(1, verbose_stream() << "(opt.maxres [" << m_lower << ":" << m_upper << "])\n";);
vector<ptr_vector<expr> > cores;
ptr_vector<expr> mss;
vector<exprs> cores;
exprs mss;
model_ref mdl;
expr_ref tmp(m);
mcs.reset();
s().get_model(mdl);
update_assignment(mdl.get());
mss.append(m_asms.size(), m_asms.c_ptr());
is_sat = m_mss(cores, mss, mcs);
is_sat = get_mss(cores, mss, mcs);
switch (is_sat) {
case l_undef:
@ -244,9 +245,7 @@ public:
if (is_sat != l_true) {
return is_sat;
}
model_ref mdl;
m_mss.get_model(mdl);
update_assignment(mdl.get());
update_mss_model();
break;
}
}
@ -285,11 +284,12 @@ public:
*/
lbool mus_mss2_solver() {
m_all_cores = true;
m_add_upper_bound_block = true;
//m_add_upper_bound_block = true;
init();
init_local();
sls();
vector<ptr_vector<expr> > cores;
vector<exprs> cores;
m_mus.set_soft(m_soft.size(), m_soft.c_ptr(), m_weights.c_ptr());
lbool is_sat = l_true;
while (m_lower < m_upper && is_sat == l_true) {
TRACE("opt",
@ -307,7 +307,7 @@ public:
found_optimum();
return l_true;
case l_false:
is_sat = process_unsat(cores);
is_sat = get_cores(cores);
break;
default:
break;
@ -315,27 +315,42 @@ public:
if (is_sat == l_undef) {
return l_undef;
}
SASSERT((is_sat == l_false) == cores.empty());
SASSERT((is_sat == l_true) == !cores.empty());
if (cores.empty()) {
SASSERT(is_sat == l_false);
break;
}
SASSERT(is_sat == l_true);
// TBD: there is some best model,
// retrieve it from the get_cores calls.
// extend it to a maximal assignment
// extracting the mss and mcs.
set_mus(false);
ptr_vector<expr> mss, mcs;
is_sat = m_mss(cores, mss, mcs);
set_mus(true);
//
// There is a best model,
// retrieve it from the previous
// core calls.
//
update_mus_model();
//
// Extend the current model to a (maximal)
// assignment extracting the ss and cs.
// ss - satisfying subset
// cs - correction set (complement of it).
//
exprs ss, cs;
is_sat = get_mss(cores, ss, cs);
if (is_sat != l_true) return is_sat;
update_mss_model();
//
// block the hard constraints corresponding to the cores.
// block the soft constraints corresponding to the cs.
// The original cs is not disjoint from the cores,
// after the cores are blocked, the soft constraints
// are changed.
//
is_sat = process_unsat(cores);
if (is_sat != l_true) return is_sat;
get_current_correction_set(cs);
is_sat = process_sat(cs);
if (is_sat != l_true) return is_sat;
model_ref mdl;
m_mss.get_model(mdl); // last model is best way to reduce search space.
update_assignment(mdl.get());
is_sat = process_sat(mcs);
}
m_lower = m_upper;
return l_true;
}
@ -370,12 +385,12 @@ public:
return l_undef;
}
lbool get_cores(vector<ptr_vector<expr> >& cores) {
lbool get_cores(vector<exprs>& cores) {
// assume m_s is unsat.
lbool is_sat = l_false;
expr_ref_vector asms(m_asms);
cores.reset();
ptr_vector<expr> core;
exprs core;
while (is_sat == l_false) {
core.reset();
s().get_unsat_core(core);
@ -420,6 +435,18 @@ public:
return is_sat;
}
void get_current_correction_set(exprs& cs) {
TRACE("opt", display_vec(tout << "old correction set: ", cs.size(), cs.c_ptr()););
cs.reset();
expr_ref tmp(m);
for (unsigned i = 0; i < m_asms.size(); ++i) {
VERIFY(m_model->eval(m_asms[i].get(), tmp));
if (!m.is_true(tmp)) {
cs.push_back(m_asms[i].get());
}
}
TRACE("opt", display_vec(tout << "new correction set: ", cs.size(), cs.c_ptr()););
}
struct compare_asm {
maxres& mr;
@ -431,7 +458,7 @@ public:
void sort_assumptions(expr_ref_vector& _asms) {
compare_asm comp(*this);
ptr_vector<expr> asms(_asms.size(), _asms.c_ptr());
exprs asms(_asms.size(), _asms.c_ptr());
expr_ref_vector trail(_asms);
std::sort(asms.begin(), asms.end(), comp);
_asms.reset();
@ -451,7 +478,7 @@ public:
return index;
}
lbool process_sat(ptr_vector<expr> const& corr_set) {
lbool process_sat(exprs const& corr_set) {
expr_ref fml(m), tmp(m);
TRACE("opt", display_vec(tout << "corr_set: ", corr_set.size(), corr_set.c_ptr()););
remove_core(corr_set);
@ -461,11 +488,7 @@ public:
}
lbool process_unsat() {
vector<ptr_vector<expr> > cores;
return process_unsat(cores);
}
lbool process_unsat(vector<ptr_vector<expr> >& cores) {
vector<exprs> cores;
lbool is_sat = get_cores(cores);
if (is_sat != l_true) {
return is_sat;
@ -473,13 +496,20 @@ public:
if (cores.empty()) {
return l_false;
}
else {
return process_unsat(cores);
}
}
lbool process_unsat(vector<exprs>& cores) {
lbool is_sat = l_true;
for (unsigned i = 0; is_sat == l_true && i < cores.size(); ++i) {
is_sat = process_unsat(cores[i]);
}
return is_sat;
}
lbool process_unsat(ptr_vector<expr> const& core) {
lbool process_unsat(exprs const& core) {
expr_ref fml(m);
remove_core(core);
SASSERT(!core.empty());
@ -493,7 +523,33 @@ public:
return l_true;
}
lbool minimize_core(ptr_vector<expr>& core) {
void update_mus_model() {
if (!m_c.sat_enabled()) {
model_ref mdl;
rational w = m_mus.get_best_model(mdl);
if (mdl.get() && w < m_upper) {
update_assignment(mdl.get());
}
}
}
void update_mss_model() {
model_ref mdl;
m_mss.get_model(mdl); // last model is best way to reduce search space.
update_assignment(mdl.get());
}
lbool get_mss(vector<exprs> const& cores, exprs& literals, exprs& mcs) {
literals.reset();
mcs.reset();
literals.append(m_asms.size(), m_asms.c_ptr());
set_mus(false);
lbool is_sat = m_mss(m_model.get(), cores, literals, mcs);
set_mus(true);
return is_sat;
}
lbool minimize_core(exprs& core) {
if (m_c.sat_enabled() || core.empty()) {
return l_true;
}
@ -527,7 +583,7 @@ public:
enable_sls(m_asms, ws);
}
rational split_core(ptr_vector<expr> const& core) {
rational split_core(exprs const& core) {
if (core.empty()) return rational(0);
// find the minimal weight:
rational w = get_weight(core[0]);
@ -562,7 +618,7 @@ public:
}
}
void max_resolve(ptr_vector<expr> const& core, rational const& w) {
void max_resolve(exprs const& core, rational const& w) {
SASSERT(!core.empty());
expr_ref fml(m), asum(m);
app_ref cls(m), d(m), dd(m);
@ -604,7 +660,7 @@ public:
}
// cs is a correction set (a complement of a (maximal) satisfying assignment).
void cs_max_resolve(ptr_vector<expr> const& cs, rational const& w) {
void cs_max_resolve(exprs const& cs, rational const& w) {
if (cs.empty()) return;
TRACE("opt", display_vec(tout << "correction set: ", cs.size(), cs.c_ptr()););
expr_ref fml(m), asum(m);
@ -645,10 +701,10 @@ public:
s().assert_expr(fml);
}
lbool try_improve_bound(vector<ptr_vector<expr> >& cores, ptr_vector<expr>& mcs) {
lbool try_improve_bound(vector<exprs>& cores, exprs& mcs) {
cores.reset();
mcs.reset();
ptr_vector<expr> core;
exprs core;
expr_ref_vector asms(m_asms);
while (true) {
rational upper = m_max_upper;
@ -662,16 +718,15 @@ public:
model_ref mdl;
s().get_model(mdl); // last model is best way to reduce search space.
update_assignment(mdl.get());
ptr_vector<expr> mss;
exprs mss;
mss.append(asms.size(), asms.c_ptr());
set_mus(false);
is_sat = m_mss(cores, mss, mcs);
is_sat = m_mss(m_model.get(), cores, mss, mcs);
set_mus(true);
if (is_sat != l_true) {
return is_sat;
}
m_mss.get_model(mdl); // last model is best way to reduce search space.
update_assignment(mdl.get());
update_mss_model();
if (!cores.empty() && mcs.size() > cores.back().size()) {
mcs.reset();
}
@ -753,7 +808,7 @@ public:
}
}
void remove_soft(ptr_vector<expr> const& core, expr_ref_vector& asms) {
void remove_soft(exprs const& core, expr_ref_vector& asms) {
for (unsigned i = 0; i < asms.size(); ++i) {
if (core.contains(asms[i].get())) {
asms[i] = asms.back();
@ -763,7 +818,7 @@ public:
}
}
void remove_core(ptr_vector<expr> const& core) {
void remove_core(exprs const& core) {
remove_soft(core, m_asms);
}
@ -811,7 +866,7 @@ opt::maxsmt_solver_base* opt::mk_maxres(
opt::maxsmt_solver_base* opt::mk_mus_mss_maxres(
context& c, weights_t& ws, expr_ref_vector const& soft) {
return alloc(maxres, c, ws, soft, maxres::s_mus_mss);
return alloc(maxres, c, ws, soft, maxres::s_mus_mss2);
}
opt::maxsmt_solver_base* opt::mk_mss_maxres(

4
src/opt/mss.cpp
View file

@ -144,10 +144,10 @@ namespace opt {
m_todo.resize(j);
}
lbool mss::operator()(vector<exprs> const& _cores, exprs& literals, exprs& mcs) {
lbool mss::operator()(model* initial_model, vector<exprs> const& _cores, exprs& literals, exprs& mcs) {
m_mss.reset();
m_todo.reset();
m_s.get_model(m_model);
m_model = initial_model;
m_cores.reset();
SASSERT(m_model);
m_cores.append(_cores);

2
src/opt/mss.h
View file

@ -36,7 +36,7 @@ namespace opt {
mss(solver& s, ast_manager& m);
~mss();
lbool operator()(vector<exprs> const& cores, exprs& literals, exprs& mcs);
lbool operator()(model* initial_model, vector<exprs> const& cores, exprs& literals, exprs& mcs);
void set_cancel(bool f) { m_cancel = f; }