mirrors/z3
3
0
Fork 0
mirror of https://github.com/Z3Prover/z3 synced 2025-08-04 02:10:23 +00:00
Code Activity

enable proof production with difference logic, integrate with PDR engine

Browse source 
Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2012-10-20 04:25:58 -07:00
parent 28a4f51ea5
commit 2e73957f97
10 changed files with 500 additions and 385 deletions
Download patch file Download diff file Expand all files Collapse all files

362
lib/pdr_util.cpp
View file

@ -41,48 +41,51 @@ Notes:
#include "pdr_prop_solver.h"
#include "pdr_util.h"
#include "arith_decl_plugin.h"
#include "expr_replacer.h"
#include "static_features.h"
namespace pdr {
unsigned ceil_log2(unsigned u)
{
if (u==0) { return 0; }
unsigned pow2 = next_power_of_two(u);
return get_num_1bits(pow2-1);
}
std::string pp_cube(const ptr_vector<expr>& model, ast_manager& m) {
return pp_cube(model.size(), model.c_ptr(), m);
}
std::string pp_cube(const expr_ref_vector& model, ast_manager& m) {
return pp_cube(model.size(), model.c_ptr(), m);
}
std::string pp_cube(const app_ref_vector& model, ast_manager& m) {
return pp_cube(model.size(), model.c_ptr(), m);
}
std::string pp_cube(const app_vector& model, ast_manager& m) {
return pp_cube(model.size(), model.c_ptr(), m);
}
std::string pp_cube(unsigned sz, app * const * lits, ast_manager& m) {
return pp_cube(sz, reinterpret_cast<expr * const *>(lits), m);
}
std::string pp_cube(unsigned sz, expr * const * lits, ast_manager& m) {
std::stringstream res;
res << "(";
expr * const * end = lits+sz;
for (expr * const * it = lits; it!=end; it++) {
res << mk_pp(*it, m);
if (it+1!=end) {
res << ", ";
}
unsigned ceil_log2(unsigned u) {
if (u == 0) { return 0; }
unsigned pow2 = next_power_of_two(u);
return get_num_1bits(pow2-1);
}
std::string pp_cube(const ptr_vector<expr>& model, ast_manager& m) {
return pp_cube(model.size(), model.c_ptr(), m);
}
std::string pp_cube(const expr_ref_vector& model, ast_manager& m) {
return pp_cube(model.size(), model.c_ptr(), m);
}
std::string pp_cube(const app_ref_vector& model, ast_manager& m) {
return pp_cube(model.size(), model.c_ptr(), m);
}
std::string pp_cube(const app_vector& model, ast_manager& m) {
return pp_cube(model.size(), model.c_ptr(), m);
}
std::string pp_cube(unsigned sz, app * const * lits, ast_manager& m) {
return pp_cube(sz, reinterpret_cast<expr * const *>(lits), m);
}
std::string pp_cube(unsigned sz, expr * const * lits, ast_manager& m) {
std::stringstream res;
res << "(";
expr * const * end = lits+sz;
for (expr * const * it = lits; it!=end; it++) {
res << mk_pp(*it, m);
if (it+1!=end) {
res << ", ";
}
}
res << ")";
return res.str();
}
res << ")";
return res.str();
}
/////////////////////////
@ -105,7 +108,7 @@ void model_evaluator::assign_value(expr* e, expr* val) {
set_value(e, val);
}
else {
IF_VERBOSE(2, verbose_stream() << "Not evaluated " << mk_pp(e, m) << "\n";);
IF_VERBOSE(3, verbose_stream() << "Not evaluated " << mk_pp(e, m) << "\n";);
TRACE("pdr", tout << "Variable is not tracked: " << mk_pp(e, m) << "\n";);
set_x(e);
}
@ -673,8 +676,7 @@ void model_evaluator::eval_basic(app* e) {
}
bool model_evaluator::check_model(ptr_vector<expr> const& formulas) {
ptr_vector<expr> todo;
assign_vector_with_casting(todo, formulas);
ptr_vector<expr> todo(formulas);
while (!todo.empty()) {
expr * curr_e = todo.back();
@ -735,69 +737,235 @@ bool model_evaluator::check_model(ptr_vector<expr> const& formulas) {
return !has_x;
}
func_decl * mk_store(ast_manager& m, sort * arr_sort)
{
family_id array_fid = m.get_family_id(symbol("array"));
unsigned num_params = arr_sort->get_num_parameters();
ptr_vector<sort> domain;
domain.push_back(arr_sort);
//we push params of the array as remaining arguments of the store. The first
//num_params-1 parameters are indices and the last one is the range of the array
for (unsigned i=0; i<num_params; ++i) {
domain.push_back(to_sort(arr_sort->get_parameter(i).get_ast()));
func_decl * mk_store(ast_manager& m, sort * arr_sort)
{
family_id array_fid = m.get_family_id(symbol("array"));
unsigned num_params = arr_sort->get_num_parameters();
ptr_vector<sort> domain;
domain.push_back(arr_sort);
//we push params of the array as remaining arguments of the store. The first
//num_params-1 parameters are indices and the last one is the range of the array
for (unsigned i=0; i<num_params; ++i) {
domain.push_back(to_sort(arr_sort->get_parameter(i).get_ast()));
}
return m.mk_func_decl(array_fid, OP_STORE,
arr_sort->get_num_parameters(), arr_sort->get_parameters(),
domain.size(), domain.c_ptr(), arr_sort);
}
return m.mk_func_decl(array_fid, OP_STORE,
arr_sort->get_num_parameters(), arr_sort->get_parameters(),
domain.size(), domain.c_ptr(), arr_sort);
}
void get_as_array_value(const model_core & mdl, expr * arr_e, expr_ref& res) {
ast_manager& m = mdl.get_manager();
array_util pl(m);
SASSERT(pl.is_as_array(arr_e));
app * arr = to_app(arr_e);
unsigned sz = 0;
func_decl_ref f(pl.get_as_array_func_decl(arr), m);
sort * arr_sort = arr->get_decl()->get_range();
func_interp* g = mdl.get_func_interp(f);
res = pl.mk_const_array(arr_sort, g->get_else());
void get_as_array_value(const model_core & mdl, expr * arr_e, expr_ref& res) {
ast_manager& m = mdl.get_manager();
array_util pl(m);
SASSERT(pl.is_as_array(arr_e));
app * arr = to_app(arr_e);
unsigned sz = 0;
func_decl_ref f(pl.get_as_array_func_decl(arr), m);
sort * arr_sort = arr->get_decl()->get_range();
func_interp* g = mdl.get_func_interp(f);
res = pl.mk_const_array(arr_sort, g->get_else());
unsigned arity = f->get_arity();
sz = g->num_entries();
if (sz) {
func_decl_ref store_fn(mk_store(m, arr_sort), m);
ptr_vector<expr> store_args;
for (unsigned i = 0; i < sz; ++i) {
const func_entry * fe = g->get_entry(i);
store_args.reset();
store_args.push_back(res);
store_args.append(arity, fe->get_args());
store_args.push_back(fe->get_result());
res = m.mk_app(store_fn, store_args.size(), store_args.c_ptr());
unsigned arity = f->get_arity();
sz = g->num_entries();
if (sz) {
func_decl_ref store_fn(mk_store(m, arr_sort), m);
ptr_vector<expr> store_args;
for (unsigned i = 0; i < sz; ++i) {
const func_entry * fe = g->get_entry(i);
store_args.reset();
store_args.push_back(res);
store_args.append(arity, fe->get_args());
store_args.push_back(fe->get_result());
res = m.mk_app(store_fn, store_args.size(), store_args.c_ptr());
}
}
}
}
void get_value_from_model(const model_core & mdl, func_decl * f, expr_ref& res) {
SASSERT(f->get_arity()==0);
ast_manager& m = mdl.get_manager();
res = mdl.get_const_interp(f);
array_util pl(m);
if (pl.is_as_array(res)) {
get_as_array_value(mdl, res, res);
void get_value_from_model(const model_core & mdl, func_decl * f, expr_ref& res) {
SASSERT(f->get_arity()==0);
ast_manager& m = mdl.get_manager();
res = mdl.get_const_interp(f);
array_util pl(m);
if (pl.is_as_array(res)) {
get_as_array_value(mdl, res, res);
}
}
}
void reduce_disequalities(model& model, unsigned threshold, expr_ref& fml) {
ast_manager& m = fml.get_manager();
expr_ref_vector conjs(m);
datalog::flatten_and(fml, conjs);
obj_map<expr, unsigned> diseqs;
expr* n, *lhs, *rhs;
for (unsigned i = 0; i < conjs.size(); ++i) {
if (m.is_not(conjs[i].get(), n) &&
m.is_eq(n, lhs, rhs)) {
if (!m.is_value(rhs)) {
std::swap(lhs, rhs);
}
if (!m.is_value(rhs)) {
continue;
}
diseqs.insert_if_not_there2(lhs, 0)->get_data().m_value++;
}
}
expr_substitution sub(m);
unsigned orig_size = conjs.size();
unsigned num_deleted = 0;
expr_ref val(m), tmp(m);
proof_ref pr(m);
pr = m.mk_asserted(m.mk_true());
obj_map<expr, unsigned>::iterator it = diseqs.begin();
obj_map<expr, unsigned>::iterator end = diseqs.end();
for (; it != end; ++it) {
if (it->m_value >= threshold) {
model.eval(it->m_key, val);
sub.insert(it->m_key, val, pr);
conjs.push_back(m.mk_eq(it->m_key, val));
num_deleted += it->m_value;
}
}
if (orig_size < conjs.size()) {
scoped_ptr<expr_replacer> rep = mk_expr_simp_replacer(m);
rep->set_substitution(&sub);
for (unsigned i = 0; i < orig_size; ++i) {
tmp = conjs[i].get();
(*rep)(tmp);
if (m.is_true(tmp)) {
conjs[i] = conjs.back();
SASSERT(orig_size <= conjs.size());
conjs.pop_back();
SASSERT(orig_size <= 1 + conjs.size());
if (i + 1 == orig_size) {
// no-op.
}
else if (orig_size <= conjs.size()) {
// no-op
}
else {
SASSERT(orig_size == 1 + conjs.size());
--orig_size;
--i;
}
}
else {
conjs[i] = tmp;
}
}
IF_VERBOSE(2, verbose_stream() << "Deleted " << num_deleted << " disequalities " << conjs.size() << " conjuncts\n";);
}
fml = m.mk_and(conjs.size(), conjs.c_ptr());
}
class ite_hoister {
ast_manager& m;
public:
ite_hoister(ast_manager& m): m(m) {}
br_status mk_app_core(func_decl* f, unsigned num_args, expr* const* args, expr_ref& result) {
for (unsigned i = 0; i < num_args; ++i) {
expr* c, *t, *e;
if (!m.is_bool(args[i]) && m.is_ite(args[i], c, t, e)) {
expr_ref e1(m), e2(m);
ptr_vector<expr> args1(num_args, args);
args1[i] = t;
e1 = m.mk_app(f, num_args, args1.c_ptr());
args1[i] = e;
e2 = m.mk_app(f, num_args, args1.c_ptr());
result = m.mk_ite(c, e1, e2);
return BR_REWRITE3;
}
}
return BR_FAILED;
}
};
struct ite_hoister_cfg: public default_rewriter_cfg {
ite_hoister m_r;
bool rewrite_patterns() const { return false; }
br_status reduce_app(func_decl * f, unsigned num, expr * const * args, expr_ref & result, proof_ref & result_pr) {
return m_r.mk_app_core(f, num, args, result);
}
ite_hoister_cfg(ast_manager & m, params_ref const & p):m_r(m) {}
};
class ite_hoister_star : public rewriter_tpl<ite_hoister_cfg> {
ite_hoister_cfg m_cfg;
public:
ite_hoister_star(ast_manager & m, params_ref const & p):
rewriter_tpl<ite_hoister_cfg>(m, false, m_cfg),
m_cfg(m, p) {}
};
template class rewriter_tpl<ite_hoister_cfg>;
class scoped_no_proof {
ast_manager& m;
proof_gen_mode m_mode;
public:
scoped_no_proof(ast_manager& m): m(m) {
m_mode = m.proof_mode();
m.toggle_proof_mode(PGM_DISABLED);
}
~scoped_no_proof() {
m.toggle_proof_mode(m_mode);
}
};
void hoist_non_bool_if(expr_ref& fml) {
ast_manager& m = fml.get_manager();
scoped_no_proof _sp(m);
params_ref p;
ite_hoister_star ite_rw(m, p);
expr_ref tmp(m);
ite_rw(fml, tmp);
fml = tmp;
}
class test_diff_logic {
ast_manager& m;
arith_util a;
bool m_is_dl;
public:
test_diff_logic(ast_manager& m): m(m), a(m), m_is_dl(true) {}
void operator()(expr* e) {
if (m_is_dl && a.is_arith_expr(e) && !a.is_numeral(e) &&
!a.is_add(e) && !a.is_mul(e) && !m.is_bool(e)) {
m_is_dl = false;
}
}
bool is_dl() const { return m_is_dl; }
};
bool is_difference_logic(ast_manager& m, unsigned num_fmls, expr* const* fmls) {
static_features st(m);
st.collect(num_fmls, fmls);
if (st.m_num_arith_eqs != st.m_num_diff_eqs ||
st.m_num_arith_terms != st.m_num_diff_terms ||
st.m_num_arith_ineqs != st.m_num_diff_ineqs) {
return false;
}
test_diff_logic test(m);
expr_fast_mark1 mark;
for (unsigned i = 0; i < num_fmls; ++i) {
quick_for_each_expr(test, mark, fmls[i]);
}
return test.is_dl();
}
}