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update core minimization code

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2016-06-23 21:39:28 -07:00
parent 41edf5f91e
commit c72ed3e6b4
9 changed files with 287 additions and 109 deletions
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11
src/opt/maxres.cpp
View file

@ -544,18 +544,11 @@ public:
return l_true;
}
m_mus.reset();
for (unsigned i = 0; i < core.size(); ++i) {
VERIFY(i == m_mus.add_soft(core[i]));
}
unsigned_vector mus_idx;
lbool is_sat = m_mus.get_mus(mus_idx);
m_mus.add_soft(core.size(), core.c_ptr());
lbool is_sat = m_mus.get_mus(m_new_core);
if (is_sat != l_true) {
return is_sat;
}
m_new_core.reset();
for (unsigned i = 0; i < mus_idx.size(); ++i) {
m_new_core.push_back(core[mus_idx[i]]);
}
core.reset();
core.append(m_new_core);
return l_true;

8
src/qe/qsat.cpp
View file

@ -811,14 +811,10 @@ namespace qe {
}
TRACE("qe", tout << core1.size() << " " << core2.size() << "\n";);
if (core1.size() > 8) {
unsigned_vector core_idxs;
if (l_true != mus.get_mus(core_idxs)) {
if (l_true != mus.get_mus(core2)) {
return false;
}
TRACE("qe", tout << core1.size() << " -> " << core_idxs.size() << "\n";);
for (unsigned i = 0; i < core_idxs.size(); ++i) {
core2.push_back(core1[core_idxs[i]].get());
}
TRACE("qe", tout << core1.size() << " -> " << core2.size() << "\n";);
core.reset();
core.append(core2);
}

3
src/smt/params/smt_params_helper.pyg
View file

@ -61,5 +61,6 @@ def_module_params(module_name='smt',
('dack.gc', UINT, 2000, 'Dynamic ackermannization garbage collection frequency (per conflict)'),
('dack.gc_inv_decay', DOUBLE, 0.8, 'Dynamic ackermannization garbage collection decay'),
('dack.threshold', UINT, 10, ' number of times the congruence rule must be used before Leibniz\'s axiom is expanded'),
('core.validate', BOOL, False, 'validate unsat core produced by SMT context')
('core.validate', BOOL, False, 'validate unsat core produced by SMT context'),
('core.minimize', BOOL, False, 'minimize unsat core produced by SMT context')
))

42
src/smt/smt_solver.cpp
View file

@ -20,19 +20,25 @@ Notes:
#include"smt_kernel.h"
#include"reg_decl_plugins.h"
#include"smt_params.h"
#include"smt_params_helper.hpp"
#include"mus.h"
namespace smt {
class solver : public solver_na2as {
smt_params m_params;
smt_params m_smt_params;
params_ref m_params;
smt::kernel m_context;
progress_callback * m_callback;
symbol m_logic;
bool m_minimizing_core;
public:
solver(ast_manager & m, params_ref const & p, symbol const & l):
solver_na2as(m),
m_smt_params(p),
m_params(p),
m_context(m, m_params) {
m_context(m, m_smt_params),
m_minimizing_core(false) {
m_logic = l;
if (m_logic != symbol::null)
m_context.set_logic(m_logic);
@ -48,7 +54,8 @@ namespace smt {
}
virtual void updt_params(params_ref const & p) {
m_params.updt_params(p);
m_smt_params.updt_params(p);
m_params.copy(p);
m_context.updt_params(p);
}
@ -77,10 +84,37 @@ namespace smt {
return m_context.check(num_assumptions, assumptions);
}
struct scoped_minimize_core {
solver& s;
expr_ref_vector m_assumptions;
scoped_minimize_core(solver& s): s(s), m_assumptions(s.m_assumptions) {
s.m_minimizing_core = true;
s.m_assumptions.reset();
}
~scoped_minimize_core() {
s.m_minimizing_core = false;
s.m_assumptions.append(m_assumptions);
}
};
virtual void get_unsat_core(ptr_vector<expr> & r) {
unsigned sz = m_context.get_unsat_core_size();
for (unsigned i = 0; i < sz; i++)
for (unsigned i = 0; i < sz; i++) {
r.push_back(m_context.get_unsat_core_expr(i));
}
if (m_minimizing_core || smt_params_helper(m_params).core_minimize() == false) {
return;
}
scoped_minimize_core scm(*this);
mus mus(*this);
mus.add_soft(r.size(), r.c_ptr());
ptr_vector<expr> r2;
if (l_true == mus.get_mus(r2)) {
r.reset();
r.append(r2);
}
}
virtual void get_model(model_ref & m) {

286
src/solver/mus.cpp
View file

@ -22,10 +22,13 @@ Notes:
#include "mus.h"
#include "ast_pp.h"
#include "ast_util.h"
#include "uint_set.h"
#include "model_evaluator.h"
struct mus::imp {
typedef obj_hashtable<expr> expr_set;
solver& m_solver;
ast_manager& m;
expr_ref_vector m_lit2expr;
@ -56,7 +59,7 @@ struct mus::imp {
unsigned idx = m_lit2expr.size();
m_expr2lit.insert(lit, idx);
m_lit2expr.push_back(lit);
TRACE("opt", tout << idx << ": " << mk_pp(lit, m) << "\n" << m_lit2expr << "\n";);
TRACE("mus", tout << idx << ": " << mk_pp(lit, m) << "\n" << m_lit2expr << "\n";);
return idx;
}
@ -64,66 +67,61 @@ struct mus::imp {
SASSERT(is_literal(lit));
m_assumptions.push_back(lit);
}
lbool get_mus(unsigned_vector& mus) {
// SASSERT: mus does not have duplicates.
lbool get_mus(expr_ref_vector& mus) {
m_model.reset();
unsigned_vector core;
for (unsigned i = 0; i < m_lit2expr.size(); ++i) {
core.push_back(i);
}
if (core.size() == 1) {
mus.push_back(core.back());
mus.reset();
if (m_lit2expr.size() == 1) {
mus.push_back(m_lit2expr.back());
return l_true;
}
return get_mus1(mus);
}
lbool get_mus(ptr_vector<expr>& mus) {
mus.reset();
if (false && core.size() > 64) {
return qx(mus);
}
expr_ref_vector result(m);
lbool r = get_mus(result);
mus.append(result.size(), result.c_ptr());
return r;
}
expr_ref_vector assumptions(m);
lbool get_mus1(expr_ref_vector& mus) {
ptr_vector<expr> unknown(m_lit2expr.size(), m_lit2expr.c_ptr());
ptr_vector<expr> core_exprs;
while (!core.empty()) {
IF_VERBOSE(12, verbose_stream() << "(opt.mus reducing core: " << core.size() << " new core: " << mus.size() << ")\n";);
unsigned lit_id = core.back();
TRACE("opt",
display_vec(tout << "core: ", core);
display_vec(tout << "mus: ", mus);
);
core.pop_back();
expr* lit = m_lit2expr[lit_id].get();
expr_ref not_lit(m);
not_lit = mk_not(m, lit);
while (!unknown.empty()) {
IF_VERBOSE(12, verbose_stream() << "(mus reducing core: " << unknown.size() << " new core: " << mus.size() << ")\n";);
TRACE("mus", display_vec(tout << "core: ", unknown); display_vec(tout << "mus: ", mus););
expr* lit = unknown.back();
unknown.pop_back();
expr_ref not_lit(mk_not(m, lit), m);
lbool is_sat = l_undef;
{
scoped_append _sa1(*this, assumptions, core);
scoped_append _sa2(*this, assumptions, m_assumptions);
assumptions.push_back(not_lit);
is_sat = m_solver.check_sat(assumptions);
scoped_append _sa1(*this, mus, unknown);
scoped_append _sa2(*this, mus, m_assumptions);
mus.push_back(not_lit);
is_sat = m_solver.check_sat(mus);
}
switch (is_sat) {
case l_undef:
return is_sat;
case l_true:
assumptions.push_back(lit);
mus.push_back(lit_id);
mus.push_back(lit);
update_model();
break;
default:
core_exprs.reset();
m_solver.get_unsat_core(core_exprs);
if (!core_exprs.contains(not_lit)) {
// core := core_exprs \ mus
core.reset();
// unknown := core_exprs \ mus
unknown.reset();
for (unsigned i = 0; i < core_exprs.size(); ++i) {
lit = core_exprs[i];
if (m_expr2lit.find(lit, lit_id) && !mus.contains(lit_id)) {
core.push_back(lit_id);
if (!mus.contains(core_exprs[i])) {
unknown.push_back(core_exprs[i]);
}
}
TRACE("opt", display_vec(tout << "core exprs:", core_exprs);
display_vec(tout << "core:", core);
TRACE("mus", display_vec(tout << "core exprs:", core_exprs);
display_vec(tout << "core:", unknown);
display_vec(tout << "mus:", mus);
);
@ -131,36 +129,146 @@ struct mus::imp {
break;
}
}
#if 0
DEBUG_CODE(
assumptions.reset();
for (unsigned i = 0; i < mus.size(); ++i) {
assumptions.push_back(m_lit2expr[mus[i]].get());
}
lbool is_sat = m_solver.check_sat(assumptions.size(), assumptions.c_ptr());
SASSERT(is_sat == l_false);
);
#endif
// SASSERT(is_core(mus));
return l_true;
}
// use correction sets
lbool get_mus2(expr_ref_vector& mus) {
expr* lit = 0;
lbool is_sat;
ptr_vector<expr> unknown(m_lit2expr.size(), m_lit2expr.c_ptr());
while (!unknown.empty()) {
IF_VERBOSE(12, verbose_stream() << "(mus reducing core: " << unknown.size() << " new core: " << mus.size() << ")\n";);
{
scoped_append _sa1(*this, mus, m_assumptions);
is_sat = get_next_mcs(mus, unknown, lit);
}
if (l_false == is_sat) {
mus.push_back(lit);
}
else {
return is_sat;
}
}
//SASSERT(is_core(mus));
return l_true;
}
// find the next literal to be a member of a core.
lbool get_next_mcs(expr_ref_vector& mus, ptr_vector<expr>& unknown, expr*& core_literal) {
ptr_vector<expr> mss;
expr_ref_vector nmcs(m);
expr_set core, min_core, nmcs_set;
bool min_core_valid = false;
expr* min_lit = 0;
while (!unknown.empty()) {
expr* lit = unknown.back();
unknown.pop_back();
model_ref mdl;
scoped_append assume_mss(*this, mus, mss); // current satisfied literals
scoped_append assume_nmcs(*this, mus, nmcs); // current non-satisfied literals
scoped_append assume_lit(*this, mus, lit); // current unknown literal
switch (m_solver.check_sat(mus)) {
case l_true: {
TRACE("mus", tout << "literal can be satisfied: " << mk_pp(lit, m) << "\n";);
mss.push_back(lit);
m_solver.get_model(mdl);
model_evaluator eval(*mdl.get());
for (unsigned i = 0; i < unknown.size(); ) {
expr_ref tmp(m);
eval(unknown[i], tmp);
if (m.is_true(tmp)) {
mss.push_back(unknown[i]);
unknown[i] = unknown.back();
unknown.pop_back();
}
else {
++i;
}
}
break;
}
case l_false:
TRACE("mus", tout << "literal is in a core: " << mk_pp(lit, m) << "\n";);
nmcs.push_back(mk_not(m, lit));
nmcs_set.insert(nmcs.back());
get_core(core);
if (!core.contains(lit)) {
// The current mus is already a core.
unknown.reset();
return l_true;
}
if (have_intersection(nmcs_set, core)) {
// can't use this core directly. Hypothetically, we
// could try to combine min_core with core and
// see if the combination produces a better minimal core.
SASSERT(min_core_valid);
break;
}
if (!min_core_valid || core.size() < min_core.size()) {
// The current core is smallest so far, so we get fewer unknowns from it.
min_core = core;
min_core_valid = true;
min_lit = lit;
}
break;
case l_undef:
return l_undef;
}
}
SASSERT(min_core_valid);
if (!min_core_valid) {
// all unknown soft constraints were satisfiable
return l_true;
}
expr_set mss_set;
for (unsigned i = 0; i < mss.size(); ++i) {
mss_set.insert(mss[i]);
}
expr_set::iterator it = min_core.begin(), end = min_core.end();
for (; it != end; ++it) {
if (mss_set.contains(*it) && min_lit != *it) {
unknown.push_back(*it);
}
}
core_literal = min_lit;
return l_false;
}
bool have_intersection(expr_set const& A, expr_set const& B) {
if (A.size() < B.size()) {
expr_set::iterator it = A.begin(), end = A.end();
for (; it != end; ++it) {
if (B.contains(*it)) return true;
}
}
else {
expr_set::iterator it = B.begin(), end = B.end();
for (; it != end; ++it) {
if (A.contains(*it)) return true;
}
}
return false;
}
bool is_core(expr_ref_vector const& mus) {
return l_false == m_solver.check_sat(mus);
}
class scoped_append {
expr_ref_vector& m_fmls;
unsigned m_size;
public:
scoped_append(imp& imp, expr_ref_vector& fmls1, unsigned_vector const& fmls2):
scoped_append(imp& imp, expr_ref_vector& fmls1, expr_set const& fmls2):
m_fmls(fmls1),
m_size(fmls1.size()) {
for (unsigned i = 0; i < fmls2.size(); ++i) {
fmls1.push_back(imp.m_lit2expr[fmls2[i]].get());
}
}
scoped_append(imp& imp, expr_ref_vector& fmls1, uint_set const& fmls2):
m_fmls(fmls1),
m_size(fmls1.size()) {
uint_set::iterator it = fmls2.begin(), end = fmls2.end();
expr_set::iterator it = fmls2.begin(), end = fmls2.end();
for (; it != end; ++it) {
fmls1.push_back(imp.m_lit2expr[*it].get());
fmls1.push_back(*it);
}
}
scoped_append(imp& imp, expr_ref_vector& fmls1, expr_ref_vector const& fmls2):
@ -168,17 +276,21 @@ struct mus::imp {
m_size(fmls1.size()) {
fmls1.append(fmls2);
}
scoped_append(imp& imp, expr_ref_vector& fmls1, ptr_vector<expr> const& fmls2):
m_fmls(fmls1),
m_size(fmls1.size()) {
fmls1.append(fmls2.size(), fmls2.c_ptr());
}
scoped_append(imp& imp, expr_ref_vector& fmls1, expr* fml):
m_fmls(fmls1),
m_size(fmls1.size()) {
fmls1.push_back(fml);
}
~scoped_append() {
m_fmls.shrink(m_size);
}
};
void add_core(unsigned_vector const& core, expr_ref_vector& assumptions) {
for (unsigned i = 0; i < core.size(); ++i) {
assumptions.push_back(m_lit2expr[core[i]].get());
}
}
template<class T>
void display_vec(std::ostream& out, T const& v) const {
for (unsigned i = 0; i < v.size(); ++i) {
@ -234,14 +346,14 @@ struct mus::imp {
}
lbool qx(unsigned_vector& mus) {
uint_set core, support;
lbool qx(expr_ref_vector& mus) {
expr_set core, support;
for (unsigned i = 0; i < m_lit2expr.size(); ++i) {
core.insert(i);
core.insert(m_lit2expr[i].get());
}
lbool is_sat = qx(core, support, false);
if (is_sat == l_true) {
uint_set::iterator it = core.begin(), end = core.end();
expr_set::iterator it = core.begin(), end = core.end();
mus.reset();
for (; it != end; ++it) {
mus.push_back(*it);
@ -250,7 +362,7 @@ struct mus::imp {
return is_sat;
}
lbool qx(uint_set& assignment, uint_set& support, bool has_support) {
lbool qx(expr_set& assignment, expr_set& support, bool has_support) {
lbool is_sat = l_true;
#if 0
if (s.m_config.m_minimize_core_partial && s.m_stats.m_restart - m_restart > m_max_restarts) {
@ -265,7 +377,7 @@ struct mus::imp {
is_sat = m_solver.check_sat(asms);
switch (is_sat) {
case l_false: {
uint_set core;
expr_set core;
get_core(core);
support &= core;
assignment.reset();
@ -280,10 +392,10 @@ struct mus::imp {
break;
}
}
if (assignment.num_elems() == 1) {
if (assignment.size() == 1) {
return l_true;
}
uint_set assign2;
expr_set assign2;
split(assignment, assign2);
support |= assignment;
is_sat = qx(assign2, support, !assignment.empty());
@ -296,20 +408,20 @@ struct mus::imp {
return is_sat;
}
void get_core(uint_set& core) {
void get_core(expr_set& core) {
core.reset();
ptr_vector<expr> core_exprs;
unsigned lit_id;
m_solver.get_unsat_core(core_exprs);
for (unsigned i = 0; i < core_exprs.size(); ++i) {
if (m_expr2lit.find(core_exprs[i], lit_id)) {
core.insert(lit_id);
if (m_expr2lit.contains(core_exprs[i])) {
core.insert(core_exprs[i]);
}
}
}
void unsplit(uint_set& A, uint_set& B) {
uint_set A1, B1;
uint_set::iterator it = A.begin(), end = A.end();
void unsplit(expr_set& A, expr_set& B) {
expr_set A1, B1;
expr_set::iterator it = A.begin(), end = A.end();
for (; it != end; ++it) {
if (B.contains(*it)) {
B1.insert(*it);
@ -322,10 +434,10 @@ struct mus::imp {
B = B1;
}
void split(uint_set& lits1, uint_set& lits2) {
unsigned half = lits1.num_elems()/2;
uint_set lits3;
uint_set::iterator it = lits1.begin(), end = lits1.end();
void split(expr_set& lits1, expr_set& lits2) {
unsigned half = lits1.size()/2;
expr_set lits3;
expr_set::iterator it = lits1.begin(), end = lits1.end();
for (unsigned i = 0; it != end; ++it, ++i) {
if (i < half) {
lits3.insert(*it);
@ -355,7 +467,11 @@ void mus::add_assumption(expr* lit) {
return m_imp->add_assumption(lit);
}
lbool mus::get_mus(unsigned_vector& mus) {
lbool mus::get_mus(ptr_vector<expr>& mus) {
return m_imp->get_mus(mus);
}
lbool mus::get_mus(expr_ref_vector& mus) {
return m_imp->get_mus(mus);
}

8
src/solver/mus.h
View file

@ -33,6 +33,10 @@ class mus {
Assume also that cls is a literal.
*/
unsigned add_soft(expr* cls);
void add_soft(unsigned sz, expr* const* clss) {
for (unsigned i = 0; i < sz; ++i) add_soft(clss[i]);
}
/**
Additional assumption for solver to be used along with solver context,
@ -43,7 +47,9 @@ class mus {
*/
void add_assumption(expr* lit);
lbool get_mus(unsigned_vector& mus);
lbool get_mus(ptr_vector<expr>& mus);
lbool get_mus(expr_ref_vector& mus);
void reset();

1
src/solver/solver_na2as.h
View file

@ -25,6 +25,7 @@ Notes:
#include"solver.h"
class solver_na2as : public solver {
protected:
ast_manager & m;
expr_ref_vector m_assumptions;
unsigned_vector m_scopes;

36
src/util/hashtable.h
View file

@ -556,6 +556,38 @@ public:
out << "]";
}
core_hashtable& operator|=(core_hashtable const& other) {
if (this == &other) return *this;
iterator i = begin(), e = end();
for (; i != e; ++i) {
insert(*i);
}
return *this;
}
core_hashtable& operator&=(core_hashtable const& other) {
if (this == &other) return *this;
core_hashtable copy(*this);
iterator i = copy.begin(), e = copy.end();
for (; i != e; ++i) {
if (!other.contains(*i)) {
remove(*i);
}
}
return *this;
}
core_hashtable& operator=(core_hashtable const& other) {
if (this == &other) return *this;
reset();
core_hashtable::iterator i = other.begin(), e = other.end();
for (; i != e; ++i) {
insert(*i);
}
return *this;
}
#ifdef Z3DEBUG
bool check_invariant() {
entry * curr = m_table;
@ -582,9 +614,6 @@ public:
unsigned long long get_num_collision() const { return 0; }
#endif
private:
core_hashtable& operator=(core_hashtable const&);
};
@ -640,4 +669,5 @@ public:
core_hashtable<int_hash_entry<INT_MIN, INT_MIN + 1>, HashProc, EqProc>(initial_capacity, h, e) {}
};
#endif /* HASHTABLE_H_ */

1
src/util/obj_hashtable.h
View file

@ -51,6 +51,7 @@ class obj_hashtable : public core_hashtable<obj_hash_entry<T>, obj_ptr_hash<T>,
public:
obj_hashtable(unsigned initial_capacity = DEFAULT_HASHTABLE_INITIAL_CAPACITY):
core_hashtable<obj_hash_entry<T>, obj_ptr_hash<T>, ptr_eq<T> >(initial_capacity) {}
};
template<typename Key, typename Value>