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z3/src/model/model_evaluator.cpp
Nikolaj Bjorner 450da5ea0c moving model_evaluator to model 
Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
2018-06-15 17:40:54 -07:00

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/*++
Copyright (c) 2011 Microsoft Corporation
Module Name:
model_evaluator.cpp
Abstract:
Evaluate expressions in a given model.
Author:
Leonardo de Moura (leonardo) 2011-04-30.
Revision History:
--*/
#include "model/model.h"
#include "model/model_evaluator_params.hpp"
#include "ast/rewriter/rewriter_types.h"
#include "model/model_evaluator.h"
#include "ast/rewriter/bool_rewriter.h"
#include "ast/rewriter/arith_rewriter.h"
#include "ast/rewriter/bv_rewriter.h"
#include "ast/rewriter/pb_rewriter.h"
#include "ast/rewriter/seq_rewriter.h"
#include "ast/rewriter/datatype_rewriter.h"
#include "ast/rewriter/array_rewriter.h"
#include "ast/rewriter/fpa_rewriter.h"
#include "ast/rewriter/rewriter_def.h"
#include "util/cooperate.h"
#include "ast/ast_pp.h"
#include "ast/ast_util.h"
#include "model/model_smt2_pp.h"
#include "ast/rewriter/var_subst.h"
struct evaluator_cfg : public default_rewriter_cfg {
ast_manager & m;
model_core & m_model;
bool_rewriter m_b_rw;
arith_rewriter m_a_rw;
bv_rewriter m_bv_rw;
array_rewriter m_ar_rw;
datatype_rewriter m_dt_rw;
pb_rewriter m_pb_rw;
fpa_rewriter m_f_rw;
seq_rewriter m_seq_rw;
array_util m_ar;
unsigned long long m_max_memory;
unsigned m_max_steps;
bool m_model_completion;
bool m_cache;
bool m_array_equalities;
bool m_array_as_stores;
evaluator_cfg(ast_manager & m, model_core & md, params_ref const & p):
m(m),
m_model(md),
m_b_rw(m),
// We must allow customers to set parameters for arithmetic rewriter/evaluator.
// In particular, the maximum degree of algebraic numbers that will be evaluated.
m_a_rw(m, p),
m_bv_rw(m),
// See comment above. We want to allow customers to set :sort-store
m_ar_rw(m, p),
m_dt_rw(m),
m_pb_rw(m),
m_f_rw(m),
m_seq_rw(m),
m_ar(m) {
bool flat = true;
m_b_rw.set_flat(flat);
m_a_rw.set_flat(flat);
m_bv_rw.set_flat(flat);
m_bv_rw.set_mkbv2num(true);
m_ar_rw.set_expand_select_store(true);
m_ar_rw.set_expand_select_ite(true);
updt_params(p);
//add_unspecified_function_models(md);
}
void updt_params(params_ref const & _p) {
model_evaluator_params p(_p);
m_max_memory = megabytes_to_bytes(p.max_memory());
m_max_steps = p.max_steps();
m_cache = p.cache();
m_model_completion = p.completion();
m_array_equalities = p.array_equalities();
m_array_as_stores = p.array_as_stores();
}
bool evaluate(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
func_interp * fi = m_model.get_func_interp(f);
return (fi != nullptr) && eval_fi(fi, num, args, result);
}
// Try to use the entries to quickly evaluate the fi
bool eval_fi(func_interp * fi, unsigned num, expr * const * args, expr_ref & result) {
if (fi->num_entries() == 0)
return false; // let get_macro handle it.
SASSERT(fi->get_arity() == num);
bool actuals_are_values = true;
for (unsigned i = 0; actuals_are_values && i < num; i++)
actuals_are_values = m.is_value(args[i]);
if (!actuals_are_values)
return false; // let get_macro handle it
func_entry * entry = fi->get_entry(args);
if (entry != nullptr) {
result = entry->get_result();
return true;
}
return false;
}
br_status reduce_app(func_decl * f, unsigned num, expr * const * args, expr_ref & result, proof_ref & result_pr) {
result_pr = nullptr;
family_id fid = f->get_family_id();
bool is_uninterp = fid != null_family_id && m.get_plugin(fid)->is_considered_uninterpreted(f);
if (num == 0 && (fid == null_family_id || is_uninterp)) {
expr * val = m_model.get_const_interp(f);
if (val != nullptr) {
result = val;
return BR_DONE;
}
if (m_model_completion) {
sort * s = f->get_range();
expr * val = m_model.get_some_value(s);
m_model.register_decl(f, val);
result = val;
return BR_DONE;
}
return BR_FAILED;
}
br_status st = BR_FAILED;
if (fid == m_b_rw.get_fid()) {
decl_kind k = f->get_decl_kind();
if (k == OP_EQ) {
// theory dispatch for =
SASSERT(num == 2);
family_id s_fid = m.get_sort(args[0])->get_family_id();
if (s_fid == m_a_rw.get_fid())
st = m_a_rw.mk_eq_core(args[0], args[1], result);
else if (s_fid == m_bv_rw.get_fid())
st = m_bv_rw.mk_eq_core(args[0], args[1], result);
else if (s_fid == m_dt_rw.get_fid())
st = m_dt_rw.mk_eq_core(args[0], args[1], result);
else if (s_fid == m_f_rw.get_fid())
st = m_f_rw.mk_eq_core(args[0], args[1], result);
else if (s_fid == m_seq_rw.get_fid())
st = m_seq_rw.mk_eq_core(args[0], args[1], result);
else if (s_fid == m_ar_rw.get_fid())
st = mk_array_eq(args[0], args[1], result);
if (st != BR_FAILED)
return st;
}
return m_b_rw.mk_app_core(f, num, args, result);
}
if (fid == m_a_rw.get_fid())
st = m_a_rw.mk_app_core(f, num, args, result);
else if (fid == m_bv_rw.get_fid())
st = m_bv_rw.mk_app_core(f, num, args, result);
else if (fid == m_ar_rw.get_fid())
st = m_ar_rw.mk_app_core(f, num, args, result);
else if (fid == m_dt_rw.get_fid())
st = m_dt_rw.mk_app_core(f, num, args, result);
else if (fid == m_pb_rw.get_fid())
st = m_pb_rw.mk_app_core(f, num, args, result);
else if (fid == m_f_rw.get_fid())
st = m_f_rw.mk_app_core(f, num, args, result);
else if (fid == m_seq_rw.get_fid())
st = m_seq_rw.mk_app_core(f, num, args, result);
else if (fid == m.get_label_family_id() && num == 1) {
result = args[0];
st = BR_DONE;
}
else if (evaluate(f, num, args, result)) {
TRACE("model_evaluator", tout << "reduce_app " << f->get_name() << "\n";
for (unsigned i = 0; i < num; i++) tout << mk_ismt2_pp(args[i], m) << "\n";
tout << "---->\n" << mk_ismt2_pp(result, m) << "\n";);
return BR_REWRITE1;
}
if (st == BR_FAILED && !m.is_builtin_family_id(fid))
st = evaluate_partial_theory_func(f, num, args, result, result_pr);
if (st == BR_DONE && is_app(result)) {
app* a = to_app(result);
if (evaluate(a->get_decl(), a->get_num_args(), a->get_args(), result)) {
return BR_REWRITE1;
}
}
CTRACE("model_evaluator", st != BR_FAILED, tout << result << "\n";);
return st;
}
void expand_stores(expr_ref& val) {
vector<expr_ref_vector> stores;
expr_ref else_case(m);
bool _unused;
if (m_array_as_stores &&
m_ar.is_array(val) &&
extract_array_func_interp(val, stores, else_case, _unused)) {
sort* srt = m.get_sort(val);
val = m_ar.mk_const_array(srt, else_case);
for (unsigned i = stores.size(); i-- > 0; ) {
expr_ref_vector args(m);
args.push_back(val);
args.append(stores[i].size(), stores[i].c_ptr());
val = m_ar.mk_store(args.size(), args.c_ptr());
}
}
}
bool get_macro(func_decl * f, expr * & def, quantifier * & q, proof * & def_pr) {
#define TRACE_MACRO TRACE("model_evaluator", tout << "get_macro for " << f->get_name() << " (model completion: " << m_model_completion << ")\n";);
func_interp * fi = m_model.get_func_interp(f);
if (fi != nullptr) {
TRACE_MACRO;
if (fi->is_partial()) {
if (m_model_completion) {
sort * s = f->get_range();
expr * val = m_model.get_some_value(s);
fi->set_else(val);
}
else
return false;
}
def = fi->get_interp();
SASSERT(def != 0);
return true;
}
if (m_model_completion &&
(f->get_family_id() == null_family_id ||
m.get_plugin(f->get_family_id())->is_considered_uninterpreted(f)))
{
TRACE_MACRO;
sort * s = f->get_range();
expr * val = m_model.get_some_value(s);
func_interp * new_fi = alloc(func_interp, m, f->get_arity());
new_fi->set_else(val);
m_model.register_decl(f, new_fi);
def = val;
return true;
}
return false;
}
br_status evaluate_partial_theory_func(func_decl * f,
unsigned num, expr * const * args,
expr_ref & result, proof_ref & result_pr) {
SASSERT(f != 0);
SASSERT(!m.is_builtin_family_id(f->get_family_id()));
result = nullptr;
result_pr = nullptr;
func_interp * fi = m_model.get_func_interp(f);
if (fi) {
if (fi->is_partial())
fi->set_else(m.get_some_value(f->get_range()));
var_subst vs(m, false);
vs(fi->get_interp(), num, args, result);
return BR_REWRITE_FULL;
}
return BR_FAILED;
}
bool max_steps_exceeded(unsigned num_steps) const {
cooperate("model evaluator");
if (memory::get_allocation_size() > m_max_memory)
throw rewriter_exception(Z3_MAX_MEMORY_MSG);
return num_steps > m_max_steps;
}
bool cache_results() const { return m_cache; }
br_status mk_array_eq(expr* a, expr* b, expr_ref& result) {
TRACE("model_evaluator", tout << "mk_array_eq " << m_array_equalities << "\n";);
if (a == b) {
result = m.mk_true();
return BR_DONE;
}
if (!m_array_equalities) {
return BR_FAILED;
}
vector<expr_ref_vector> stores1, stores2;
bool args_are_unique1, args_are_unique2;
expr_ref else1(m), else2(m);
if (extract_array_func_interp(a, stores1, else1, args_are_unique1) &&
extract_array_func_interp(b, stores2, else2, args_are_unique2)) {
expr_ref_vector conj(m), args1(m), args2(m);
if (m.are_equal(else1, else2)) {
// no op
}
else if (m.are_distinct(else1, else2) && !(m.get_sort(else1)->get_info()->get_num_elements().is_finite())) {
result = m.mk_false();
return BR_DONE;
}
else {
conj.push_back(m.mk_eq(else1, else2));
}
if (args_are_unique1 && args_are_unique2 && !stores1.empty()) {
TRACE("model_evalator", tout << "argss are unique";);
return mk_array_eq_core(stores1, else1, stores2, else2, conj, result);
}
// TBD: this is too inefficient.
args1.push_back(a);
args2.push_back(b);
stores1.append(stores2);
for (unsigned i = 0; i < stores1.size(); ++i) {
args1.resize(1); args1.append(stores1[i].size() - 1, stores1[i].c_ptr());
args2.resize(1); args2.append(stores1[i].size() - 1, stores1[i].c_ptr());
expr_ref s1(m_ar.mk_select(args1.size(), args1.c_ptr()), m);
expr_ref s2(m_ar.mk_select(args2.size(), args2.c_ptr()), m);
conj.push_back(m.mk_eq(s1, s2));
}
result = mk_and(conj);
TRACE("model_evaluator", tout << mk_pp(a, m) << " == " << mk_pp(b, m) << " -> " << conj << "\n";
for (auto& s : stores1) tout << "store: " << s << "\n";
);
return BR_REWRITE_FULL;
}
return BR_FAILED;
}
struct args_eq {
unsigned m_arity;
args_eq(unsigned arity): m_arity(arity) {}
bool operator()(expr * const* args1, expr* const* args2) const {
for (unsigned i = 0; i < m_arity; ++i) {
if (args1[i] != args2[i]) {
return false;
}
}
return true;
}
};
struct args_hash {
unsigned m_arity;
args_hash(unsigned arity): m_arity(arity) {}
unsigned operator()(expr * const* args) const {
return get_composite_hash(args, m_arity, default_kind_hash_proc<expr*const*>(), *this);
}
unsigned operator()(expr* const* args, unsigned idx) const {
return args[idx]->hash();
}
};
typedef hashtable<expr*const*, args_hash, args_eq> args_table;
br_status mk_array_eq_core(vector<expr_ref_vector> const& stores1, expr* else1,
vector<expr_ref_vector> const& stores2, expr* else2,
expr_ref_vector& conj, expr_ref& result) {
unsigned arity = stores1[0].size()-1; // TBD: fix arity.
args_hash ah(arity);
args_eq ae(arity);
args_table table1(DEFAULT_HASHTABLE_INITIAL_CAPACITY, ah, ae);
args_table table2(DEFAULT_HASHTABLE_INITIAL_CAPACITY, ah, ae);
// stores with smaller index take precedence
for (unsigned i = stores1.size(); i > 0; ) {
--i;
table1.insert(stores1[i].c_ptr());
}
for (unsigned i = 0, sz = stores2.size(); i < sz; ++i) {
if (table2.contains(stores2[i].c_ptr())) {
// first insertion takes precedence.
continue;
}
table2.insert(stores2[i].c_ptr());
expr * const* args = nullptr;
expr* val = stores2[i][arity];
if (table1.find(stores2[i].c_ptr(), args)) {
switch (compare(args[arity], val)) {
case l_true: table1.remove(args); break;
case l_false: result = m.mk_false(); return BR_DONE;
default: conj.push_back(m.mk_eq(val, args[arity])); break;
}
}
else {
switch (compare(else1, val)) {
case l_true: break;
case l_false: result = m.mk_false(); return BR_DONE;
default: conj.push_back(m.mk_eq(else1, val)); break;
}
}
}
for (auto const& t : table1) {
switch (compare((t)[arity], else2)) {
case l_true: break;
case l_false: result = m.mk_false(); return BR_DONE;
default: conj.push_back(m.mk_eq((t)[arity], else2)); break;
}
}
result = mk_and(conj);
return BR_REWRITE_FULL;
}
lbool compare(expr* a, expr* b) {
if (m.are_equal(a, b)) return l_true;
if (m.are_distinct(a, b)) return l_false;
return l_undef;
}
bool args_are_values(expr_ref_vector const& store, bool& are_unique) {
bool are_values = true;
for (unsigned j = 0; are_values && j + 1 < store.size(); ++j) {
are_values = m.is_value(store[j]);
are_unique &= m.is_unique_value(store[j]);
}
SASSERT(!are_unique || are_values);
return are_values;
}
bool extract_array_func_interp(expr* a, vector<expr_ref_vector>& stores, expr_ref& else_case, bool& are_unique) {
SASSERT(m_ar.is_array(a));
bool are_values = true;
are_unique = true;
TRACE("model_evaluator", tout << mk_pp(a, m) << "\n";);
while (m_ar.is_store(a)) {
expr_ref_vector store(m);
store.append(to_app(a)->get_num_args()-1, to_app(a)->get_args()+1);
are_values &= args_are_values(store, are_unique);
stores.push_back(store);
a = to_app(a)->get_arg(0);
}
if (m_ar.is_const(a)) {
else_case = to_app(a)->get_arg(0);
return true;
}
if (!m_ar.is_as_array(a)) {
TRACE("model_evaluator", tout << "no translation: " << mk_pp(a, m) << "\n";);
return false;
}
func_decl* f = m_ar.get_as_array_func_decl(to_app(a));
func_interp* g = m_model.get_func_interp(f);
if (!g) return false;
unsigned sz = g->num_entries();
unsigned arity = f->get_arity();
unsigned base_sz = stores.size();
for (unsigned i = 0; i < sz; ++i) {
expr_ref_vector store(m);
func_entry const* fe = g->get_entry(i);
store.append(arity, fe->get_args());
store.push_back(fe->get_result());
for (unsigned j = 0; j < store.size(); ++j) {
if (!is_ground(store[j].get())) {
TRACE("model_evaluator", tout << "could not extract array interpretation: " << mk_pp(a, m) << "\n" << mk_pp(store[j].get(), m) << "\n";);
return false;
}
}
stores.push_back(store);
}
else_case = g->get_else();
if (!else_case) {
TRACE("model_evaluator", tout << "no else case " << mk_pp(a, m) << "\n";
/*model_smt2_pp(tout, m, m_model, 0);*/
);
return false;
}
if (!is_ground(else_case)) {
TRACE("model_evaluator", tout << "non-ground else case " << mk_pp(a, m) << "\n" << else_case << "\n";);
return false;
}
for (unsigned i = stores.size(); are_values && i > base_sz; ) {
--i;
if (m.are_equal(else_case, stores[i].back())) {
for (unsigned j = i + 1; j < stores.size(); ++j) {
stores[j-1].reset();
stores[j-1].append(stores[j]);
}
stores.pop_back();
continue;
}
are_values &= args_are_values(stores[i], are_unique);
}
TRACE("model_evaluator", tout << "else case: " << mk_pp(else_case, m) << "\n";);
return true;
}
};
template class rewriter_tpl<evaluator_cfg>;
struct model_evaluator::imp : public rewriter_tpl<evaluator_cfg> {
evaluator_cfg m_cfg;
imp(model_core & md, params_ref const & p):
rewriter_tpl<evaluator_cfg>(md.get_manager(),
false, // no proofs for evaluator
m_cfg),
m_cfg(md.get_manager(), md, p) {
set_cancel_check(false);
}
void expand_stores(expr_ref &val) {m_cfg.expand_stores(val);}
};
model_evaluator::model_evaluator(model_core & md, params_ref const & p) {
m_imp = alloc(imp, md, p);
}
ast_manager & model_evaluator::m() const {
return m_imp->m();
}
model_evaluator::~model_evaluator() {
dealloc(m_imp);
}
void model_evaluator::updt_params(params_ref const & p) {
m_imp->cfg().updt_params(p);
}
void model_evaluator::get_param_descrs(param_descrs & r) {
model_evaluator_params::collect_param_descrs(r);
}
void model_evaluator::set_model_completion(bool f) {
m_imp->cfg().m_model_completion = f;
}
bool model_evaluator::get_model_completion() const {
return m_imp->cfg().m_model_completion;
}
void model_evaluator::set_expand_array_equalities(bool f) {
m_imp->cfg().m_array_equalities = f;
}
unsigned model_evaluator::get_num_steps() const {
return m_imp->get_num_steps();
}
void model_evaluator::cleanup(params_ref const & p) {
model_core & md = m_imp->cfg().m_model;
dealloc(m_imp);
m_imp = alloc(imp, md, p);
}
void model_evaluator::reset(params_ref const & p) {
m_imp->reset();
updt_params(p);
}
void model_evaluator::reset(model_core &model, params_ref const& p) {
dealloc(m_imp);
m_imp = alloc(imp, model, p);
}
void model_evaluator::operator()(expr * t, expr_ref & result) {
TRACE("model_evaluator", tout << mk_ismt2_pp(t, m()) << "\n";);
m_imp->operator()(t, result);
m_imp->expand_stores(result);
}
expr_ref model_evaluator::operator()(expr * t) {
TRACE("model_evaluator", tout << mk_ismt2_pp(t, m()) << "\n";);
expr_ref result(m());
this->operator()(t, result);
return result;
}
expr_ref_vector model_evaluator::operator()(expr_ref_vector const& ts) {
expr_ref_vector rs(m());
for (expr* t : ts) rs.push_back((*this)(t));
return rs;
}
bool model_evaluator::is_true(expr* t) {
expr_ref tmp(m());
return eval(t, tmp, true) && m().is_true(tmp);
}
bool model_evaluator::is_false(expr* t) {
expr_ref tmp(m());
return eval(t, tmp, true) && m().is_false(tmp);
}
bool model_evaluator::is_true(expr_ref_vector const& ts) {
for (expr* t : ts) if (!is_true(t)) return false;
return true;
}
bool model_evaluator::eval(expr* t, expr_ref& r, bool model_completion) {
set_model_completion(model_completion);
try {
r = (*this)(t);
return true;
}
catch (model_evaluator_exception &ex) {
(void)ex;
TRACE("model_evaluator", tout << ex.msg () << "\n";);
return false;
}
}
bool model_evaluator::eval(expr_ref_vector const& ts, expr_ref& r, bool model_completion) {
expr_ref tmp(m());
tmp = mk_and(ts);
return eval(tmp, r, model_completion);
}
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