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max/min

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2016-05-05 14:11:13 -07:00
parent 9e4b9ea98b
commit 5b31f54501
4 changed files with 136 additions and 193 deletions
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15
src/opt/opt_cmds.cpp
View file

@ -141,6 +141,13 @@ class alternate_min_max_cmd : public cmd {
app_ref_vector* m_vars;
svector<bool> m_is_max;
unsigned m_position;
app_ref_vector& vars(cmd_context& ctx) {
if (!m_vars) {
m_vars = alloc(app_ref_vector, ctx.m());
}
return *m_vars;
}
public:
alternate_min_max_cmd():
cmd("min-max"),
@ -150,6 +157,7 @@ public:
virtual void reset(cmd_context & ctx) {
dealloc(m_vars);
m_vars = 0;
m_is_max.reset();
m_position = 0;
}
@ -176,8 +184,7 @@ public:
}
else {
m_is_max.push_back(is_max);
if (!m_vars) m_vars = alloc(app_ref_vector, ctx.m());
m_vars->push_back(ctx.m().mk_const(ctx.find_func_decl(slist[i])));
vars(ctx).push_back(ctx.m().mk_const(ctx.find_func_decl(slist[i])));
}
}
++m_position;
@ -188,8 +195,8 @@ public:
throw cmd_exception("malformed objective term: it cannot be a quantifier or bound variable");
}
++m_position;
if (!m_vars) m_vars = alloc(app_ref_vector, ctx.m());
get_opt(ctx).min_max(to_app(t), *m_vars, m_is_max);
get_opt(ctx).min_max(to_app(t), vars(ctx), m_is_max);
reset(ctx);
}
virtual void failure_cleanup(cmd_context & ctx) {

8
src/opt/opt_context.cpp
View file

@ -218,11 +218,9 @@ namespace opt {
import_scoped_state();
normalize();
internalize();
update_solver();
solver& s = get_solver();
s.assert_expr(m_hard_constraints);
std::cout << "min-max is TBD\n";
return l_undef;
qe::max_min_opt max_min(m, m_params);
max_min.add(m_hard_constraints);
return max_min.check(is_max, vars, t);
}

295
src/qe/qsat.cpp
View file

@ -550,8 +550,7 @@ namespace qe {
unsigned m_num_rounds;
stats() { reset(); }
void reset() { memset(this, 0, sizeof(*this)); }
};
};
ast_manager& m;
params_ref m_params;
@ -706,96 +705,7 @@ namespace qe {
for (unsigned i = 0; i < vars.size(); ++i) {
m_pred_abs.fmc()->insert(vars[i]->get_decl());
}
}
#if 0
void hoist_ite(expr_ref& fml) {
app* ite;
scoped_ptr<expr_replacer> replace = mk_default_expr_replacer(m);
th_rewriter rewriter(m);
while (find_ite(fml, ite)) {
expr* cond, *th, *el;
VERIFY(m.is_ite(ite, cond, th, el));
expr_ref tmp1(fml, m), tmp2(fml, m);
replace->apply_substitution(cond, m.mk_true(), tmp1);
replace->apply_substitution(cond, m.mk_false(), tmp2);
fml = m.mk_ite(cond, tmp1, tmp2);
rewriter(fml);
}
}
bool find_ite(expr* e, app*& ite) {
ptr_vector<expr> todo;
todo.push_back(e);
ast_mark visited;
while(!todo.empty()) {
e = todo.back();
todo.pop_back();
if (visited.is_marked(e)) {
continue;
}
visited.mark(e, true);
if (m.is_ite(e) && !m.is_bool(e)) {
ite = to_app(e);
return true;
}
if (is_app(e)) {
app* a = to_app(e);
todo.append(a->get_num_args(), a->get_args());
}
}
return false;
}
// slower
void hoist_ite2(expr_ref& fml) {
obj_map<expr,expr*> result;
expr_ref_vector trail(m);
ptr_vector<expr> todo, args;
todo.push_back(fml);
while (!todo.empty()) {
expr* e = todo.back();
if (result.contains(e)) {
todo.pop_back();
continue;
}
if (!is_app(e)) {
todo.pop_back();
result.insert(e, e);
continue;
}
app* a = to_app(e);
expr* r;
unsigned sz = a->get_num_args();
args.reset();
for (unsigned i = 0; i < sz; ++i) {
if (result.find(a->get_arg(i), r)) {
args.push_back(r);
}
else {
todo.push_back(a->get_arg(i));
}
}
if (sz == args.size()) {
r = m.mk_app(a->get_decl(), args.size(), args.c_ptr());
trail.push_back(r);
if (m.is_bool(e) && m.get_basic_family_id() != a->get_family_id()) {
expr_ref fml(r, m);
hoist_ite(fml);
trail.push_back(fml);
r = fml;
}
result.insert(e, r);
todo.pop_back();
}
}
fml = result.find(fml);
}
#endif
}
void initialize_levels() {
// initialize levels.
@ -1162,7 +1072,8 @@ namespace qe {
m_level(0),
m_mode(mode),
m_avars(m),
m_free_vars(m)
m_free_vars(m),
m_kernel(m)
{
reset();
}
@ -1328,6 +1239,69 @@ namespace qe {
m_ex.assert_expr(bound);
}
kernel m_kernel;
lbool max_min(expr_ref_vector const& fmls, svector<bool> const& is_max, app_ref_vector const& vars, app* t) {
// Assume this is the only call to check.
expr_ref_vector defs(m);
app_ref_vector free_vars(m), vars1(m);
expr_ref fml = mk_and(fmls);
m_pred_abs.get_free_vars(fml, free_vars);
m_pred_abs.abstract_atoms(fml, defs);
fml = m_pred_abs.mk_abstract(fml);
m_kernel.assert_expr(mk_and(defs));
m_kernel.assert_expr(fml);
obj_hashtable<app> var_set;
for (unsigned i = 0; i < vars.size(); ++i) {
var_set.insert(vars[i]);
}
for (unsigned i = 0; i < free_vars.size(); ++i) {
app* v = free_vars[i].get();
if (!var_set.contains(v)) {
vars1.push_back(v);
}
}
//
// Insert all variables in alternating list of max/min objectives.
// By convention, the outer-most level is max.
//
bool is_m = true;
for (unsigned i = 0; i < vars.size(); ++i) {
if (is_m != is_max[i]) {
m_vars.push_back(vars1);
vars1.reset();
is_m = is_max[i];
}
vars1.push_back(vars[i]);
}
m_vars.push_back(vars1);
return max_min();
// return l_undef;
}
lbool max_min() {
while (true) {
++m_stats.m_num_rounds;
check_cancel();
expr_ref_vector asms(m_asms);
m_pred_abs.get_assumptions(m_model.get(), asms);
smt::kernel& k = get_kernel(m_level).k();
lbool res = k.check(asms);
switch (res) {
case l_true:
break;
case l_false:
break;
case l_undef:
break;
}
}
return l_undef;
}
};
lbool maximize(expr_ref_vector const& fmls, app* t, opt::inf_eps& value, model_ref& mdl, params_ref const& p) {
@ -1335,6 +1309,50 @@ namespace qe {
qsat qs(m, p, qsat_maximize);
return qs.maximize(fmls, t, mdl, value);
}
struct max_min_opt::imp {
expr_ref_vector m_fmls;
qsat m_qsat;
imp(ast_manager& m, params_ref const& p):
m_fmls(m),
m_qsat(m, p, qsat_maximize)
{}
void add(expr* e) {
m_fmls.push_back(e);
}
lbool check(svector<bool> const& is_max, app_ref_vector const& vars, app* t) {
return m_qsat.max_min(m_fmls, is_max, vars, t);
}
};
max_min_opt::max_min_opt(ast_manager& m, params_ref const& p) {
m_imp = alloc(imp, m, p);
}
max_min_opt::~max_min_opt() {
dealloc(m_imp);
}
void max_min_opt::add(expr* e) {
m_imp->add(e);
}
void max_min_opt::add(expr_ref_vector const& fmls) {
for (unsigned i = 0; i < fmls.size(); ++i) {
add(fmls[i]);
}
}
lbool max_min_opt::check(svector<bool> const& is_max, app_ref_vector const& vars, app* t) {
return m_imp->check(is_max, vars, t);
}
};
tactic * mk_qsat_tactic(ast_manager& m, params_ref const& p) {
@ -1352,94 +1370,3 @@ tactic * mk_qe_rec_tactic(ast_manager& m, params_ref const& p) {
#if 0
class min_max_opt {
struct imp;
imp* m_imp;
public:
min_max_opt(ast_manager& m);
~min_max_opt();
void add(expr* e);
void add(expr_ref_vector const& fmls);
lbool check(svector<bool> const& is_max, app_ref_vector const& vars, app* t);
};
struct min_max_opt::imp {
ast_manager& m;
expr_ref_vector m_fmls;
pred_abs m_pred_abs;
qe::mbp m_mbp;
kernel m_kernel;
vector<app_ref_vector> m_vars;
imp(ast_manager& m):
m(m),
m_fmls(m),
m_pred_abs(m),
m_mbp(m),
m_kernel(m) {}
void add(expr* e) {
m_fmls.push_back(e);
}
lbool check(svector<bool> const& is_max, app_ref_vector const& vars, app* t) {
// Assume this is the only call to check.
expr_ref_vector defs(m);
app_ref_vector free_vars(m), vars1(m);
expr_ref fml = mk_and(m_fmls);
m_pred_abs.get_free_vars(fml, free_vars);
m_pred_abs.abstract_atoms(fml, defs);
fml = m_pred_abs.mk_abstract(fml);
m_kernel.assert_expr(mk_and(defs));
m_kernel.assert_expr(fml);
obj_hashtable<app> var_set;
for (unsigned i = 0; i < vars.size(); ++i) {
var_set.insert(vars[i]);
}
for (unsigned i = 0; i < free_vars.size(); ++i) {
app* v = free_vars[i].get();
if (!var_set.contains(v)) {
vars1.push_back(v);
}
}
bool is_m = is_max[0];
for (unsigned i = 0; i < vars.size(); ++i) {
if (is_m != is_max[i]) {
m_vars.push_back(vars1);
vars1.reset();
is_m = is_max[i];
}
vars1.push_back(vars[i]);
}
// TBD
return l_undef;
}
};
min_max_opt::min_max_opt(ast_manager& m) {
m_imp = alloc(imp, m);
}
min_max_opt::~min_max_opt() {
dealloc(m_imp);
}
void min_max_opt::add(expr* e) {
m_imp->add(e);
}
void min_max_opt::add(expr_ref_vector const& fmls) {
for (unsigned i = 0; i < fmls.size(); ++i) {
add(fmls[i]);
}
}
lbool min_max_opt::check(svector<bool> const& is_max, app_ref_vector const& vars, app* t) {
return m_imp->check(is_max, vars, t);
}
#endif

11
src/qe/qsat.h
View file

@ -114,6 +114,17 @@ namespace qe {
void collect_statistics(statistics& st) const;
};
class max_min_opt {
struct imp;
imp* m_imp;
public:
max_min_opt(ast_manager& m, params_ref const& p = params_ref());
~max_min_opt();
void add(expr* e);
void add(expr_ref_vector const& fmls);
lbool check(svector<bool> const& is_max, app_ref_vector const& vars, app* t);
};
lbool maximize(expr_ref_vector const& fmls, app* t, opt::inf_eps& value, model_ref& mdl, params_ref const& p);
}