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fix for unsound results reported in #313

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2015-11-16 22:59:07 -08:00
parent b8e4871d9e
commit c8f09fa955
4 changed files with 54 additions and 24 deletions
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61
src/muz/pdr/pdr_context.cpp
View file

@ -50,6 +50,7 @@ Notes:
#include "blast_term_ite_tactic.h"
#include "model_implicant.h"
#include "expr_safe_replace.h"
#include "ast_util.h"
namespace pdr {
@ -448,6 +449,7 @@ namespace pdr {
else if (is_sat == l_false) {
uses_level = m_solver.assumes_level();
}
m_solver.set_model(0);
return is_sat;
}
@ -481,6 +483,7 @@ namespace pdr {
prop_solver::scoped_level _sl(m_solver, level);
m_solver.set_core(&core);
m_solver.set_subset_based_core(true);
m_solver.set_model(0);
lbool res = m_solver.check_assumptions_and_formula(lits, fml);
if (res == l_false) {
lits.reset();
@ -775,6 +778,13 @@ namespace pdr {
}
// only initial states are not set by the PDR search.
SASSERT(m_model.get());
if (!m_model.get()) {
std::stringstream msg;
msg << "no model for node " << state();
IF_VERBOSE(0, verbose_stream() << msg.str() << "\n";);
throw default_exception(msg.str());
}
datalog::rule const& rl1 = pt().find_rule(*m_model);
if (is_ini(rl1)) {
set_rule(&rl1);
@ -793,15 +803,23 @@ namespace pdr {
}
}
SASSERT(!tags.empty());
ini_tags = m.mk_or(tags.size(), tags.c_ptr());
ini_tags = ::mk_or(tags);
ini_state = m.mk_and(ini_tags, pt().initial_state(), state());
model_ref mdl;
pt().get_solver().set_model(&mdl);
TRACE("pdr", tout << mk_pp(ini_state, m) << "\n";);
VERIFY(l_true == pt().get_solver().check_conjunction_as_assumptions(ini_state));
TRACE("pdr", tout << ini_state << "\n";);
if (l_true != pt().get_solver().check_conjunction_as_assumptions(ini_state)) {
std::stringstream msg;
msg << "Unsatisfiable initial state: " << ini_state << "\n";
display(msg, 2);
IF_VERBOSE(0, verbose_stream() << msg.str() << "\n";);
throw default_exception(msg.str());
}
SASSERT(mdl.get());
datalog::rule const& rl2 = pt().find_rule(*mdl);
SASSERT(is_ini(rl2));
set_rule(&rl2);
pt().get_solver().set_model(0);
return const_cast<datalog::rule*>(m_rule);
}
@ -830,7 +848,7 @@ namespace pdr {
}
r0 = get_rule();
app_ref_vector& inst = pt().get_inst(r0);
TRACE("pdr", tout << mk_pp(state(), m) << " instance: " << inst.size() << "\n";);
TRACE("pdr", tout << state() << " instance: " << inst.size() << "\n";);
for (unsigned i = 0; i < inst.size(); ++i) {
expr* v;
if (model.find(inst[i].get(), v)) {
@ -852,7 +870,7 @@ namespace pdr {
for (unsigned i = 0; i < indent; ++i) out << " ";
out << m_level << " " << m_pt.head()->get_name() << " " << (m_closed?"closed":"open") << "\n";
for (unsigned i = 0; i < indent; ++i) out << " ";
out << " " << mk_pp(m_state, m_state.get_manager(), indent) << "\n";
out << " " << mk_pp(m_state, m_state.get_manager(), indent) << " " << m_state->get_id() << "\n";
for (unsigned i = 0; i < children().size(); ++i) {
children()[i]->display(out, indent + 1);
}
@ -925,17 +943,6 @@ namespace pdr {
}
}
bool model_search::is_repeated(model_node& n) const {
model_node* p = n.parent();
while (p) {
if (p->state() == n.state()) {
TRACE("pdr", tout << n.state() << "repeated\n";);
return true;
}
p = p->parent();
}
return false;
}
void model_search::add_leaf(model_node& n) {
SASSERT(n.children().empty());
@ -1012,11 +1019,11 @@ namespace pdr {
nodes.erase(&n);
bool is_goal = n.is_goal();
remove_goal(n);
if (!nodes.empty() && is_goal && backtrack) {
// TBD: siblings would also fail if n is not a goal.
if (!nodes.empty() && backtrack && nodes[0]->children().empty() && nodes[0]->is_closed()) {
TRACE("pdr_verbose", for (unsigned i = 0; i < nodes.size(); ++i) n.display(tout << &n << "\n", 2););
model_node* n1 = nodes[0];
n1->set_open();
SASSERT(n1->children().empty());
n1->set_open();
enqueue_leaf(n1);
}
@ -1702,7 +1709,15 @@ namespace pdr {
void context::validate_search() {
expr_ref tr = m_search.get_trace(*this);
// TBD: tr << "\n";
smt::kernel solver(m, get_fparams());
solver.assert_expr(tr);
lbool res = solver.check();
if (res != l_true) {
std::stringstream msg;
msg << "rule validation failed when checking: " << tr;
IF_VERBOSE(0, verbose_stream() << msg.str() << "\n";);
throw default_exception(msg.str());
}
}
void context::validate_model() {
@ -1938,11 +1953,11 @@ namespace pdr {
proof_ref proof(m);
SASSERT(m_last_result == l_true);
proof = m_search.get_proof_trace(*this);
TRACE("pdr", tout << "PDR trace: " << mk_pp(proof, m) << "\n";);
TRACE("pdr", tout << "PDR trace: " << proof << "\n";);
apply(m, m_pc.get(), proof);
TRACE("pdr", tout << "PDR trace: " << mk_pp(proof, m) << "\n";);
TRACE("pdr", tout << "PDR trace: " << proof << "\n";);
// proof_utils::push_instantiations_up(proof);
// TRACE("pdr", tout << "PDR up: " << mk_pp(proof, m) << "\n";);
// TRACE("pdr", tout << "PDR up: " << proof << "\n";);
return proof;
}

1
src/muz/pdr/pdr_context.h
View file

@ -268,7 +268,6 @@ namespace pdr {
void enqueue_leaf(model_node* n); // add leaf to priority queue.
void update_models();
void set_leaf(model_node& n); // Set node as leaf, remove children.
bool is_repeated(model_node& n) const;
unsigned num_goals() const;
public: