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fix bugs exposed in #677. to_int(x) has the semantics that to_int(x) <= x, and to_int(x) is the largest integer satisfying this inequality. The encoding in purify_arith had it the other way x <= to_int(x) contrary to how to_int(x) is handled elsewhere. Another bug in theory_arith for mixed-integer linear case was also exposed. Fractional bounds on expressions of the form to_int(x), and more generally on integer rows were not rounded prior to internalization

Browse source 
Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2016-07-13 20:32:18 -07:00
parent 63f89f8c45
commit 3989d238c0
8 changed files with 78 additions and 40 deletions
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17
src/ast/macros/macro_finder.cpp
View file

@ -22,13 +22,13 @@ Revision History:
#include"ast_pp.h"
#include"ast_ll_pp.h"
bool macro_finder::is_macro(expr * n, app * & head, expr * & def) {
bool macro_finder::is_macro(expr * n, app_ref & head, expr_ref & def) {
if (!is_quantifier(n) || !to_quantifier(n)->is_forall())
return false;
TRACE("macro_finder", tout << "processing: " << mk_pp(n, m_manager) << "\n";);
expr * body = to_quantifier(n)->get_expr();
unsigned num_decls = to_quantifier(n)->get_num_decls();
return m_util.is_simple_macro(body, num_decls, head, def);
return m_util.is_ite_macro(body, num_decls, head, def);
}
/**
@ -171,23 +171,20 @@ bool macro_finder::expand_macros(unsigned num, expr * const * exprs, proof * con
for (unsigned i = 0; i < num; i++) {
expr * n = exprs[i];
proof * pr = m_manager.proofs_enabled() ? prs[i] : 0;
expr_ref new_n(m_manager);
expr_ref new_n(m_manager), def(m_manager);
proof_ref new_pr(m_manager);
m_macro_manager.expand_macros(n, pr, new_n, new_pr);
app * head = 0;
expr * def = 0;
app * t = 0;
app_ref head(m_manager), t(m_manager);
if (is_macro(new_n, head, def) && m_macro_manager.insert(head->get_decl(), to_quantifier(new_n.get()), new_pr)) {
TRACE("macro_finder_found", tout << "found new macro: " << head->get_decl()->get_name() << "\n" << mk_pp(new_n, m_manager) << "\n";);
TRACE("macro_finder_found", tout << "found new macro: " << head->get_decl()->get_name() << "\n" << new_n << "\n";);
found_new_macro = true;
}
else if (is_arith_macro(new_n, new_pr, new_exprs, new_prs)) {
TRACE("macro_finder_found", tout << "found new arith macro:\n" << mk_pp(new_n, m_manager) << "\n";);
TRACE("macro_finder_found", tout << "found new arith macro:\n" << new_n << "\n";);
found_new_macro = true;
}
else if (m_util.is_pseudo_predicate_macro(new_n, head, t, def)) {
TRACE("macro_finder_found", tout << "found new pseudo macro:\n" << mk_pp(head, m_manager) << "\n" << mk_pp(t, m_manager) << "\n" <<
mk_pp(def, m_manager) << "\n";);
TRACE("macro_finder_found", tout << "found new pseudo macro:\n" << head << "\n" << t << "\n" << def << "\n";);
pseudo_predicate_macro2macro(m_manager, head, t, def, to_quantifier(new_n), new_pr, new_exprs, new_prs);
found_new_macro = true;
}

2
src/ast/macros/macro_finder.h
View file

@ -41,7 +41,7 @@ class macro_finder {
bool expand_macros(unsigned num, expr * const * exprs, proof * const * prs, expr_ref_vector & new_exprs, proof_ref_vector & new_prs);
bool is_arith_macro(expr * n, proof * pr, expr_ref_vector & new_exprs, proof_ref_vector & new_prs);
bool is_macro(expr * n, app * & head, expr * & def);
bool is_macro(expr * n, app_ref & head, expr_ref & def);
bool is_pseudo_head(expr * n, unsigned num_decls, app * & head, app * & t);
bool is_pseudo_predicate_macro(expr * n, app * & head, app * & t, expr * & def);

30
src/ast/macros/macro_util.cpp
View file

@ -176,7 +176,7 @@ bool macro_util::is_macro_head(expr * n, unsigned num_decls) const {
def will contain t
*/
bool macro_util::is_left_simple_macro(expr * n, unsigned num_decls, app * & head, expr * & def) const {
bool macro_util::is_left_simple_macro(expr * n, unsigned num_decls, app_ref & head, expr_ref & def) const {
if (m_manager.is_eq(n) || m_manager.is_iff(n)) {
expr * lhs = to_app(n)->get_arg(0);
expr * rhs = to_app(n)->get_arg(1);
@ -189,6 +189,22 @@ bool macro_util::is_left_simple_macro(expr * n, unsigned num_decls, app * & head
return false;
}
bool macro_util::is_ite_macro(expr * n, unsigned num_decls, app_ref& head, expr_ref& def) const {
if (is_simple_macro(n, num_decls, head, def)) {
return true;
}
expr* c, *t, *e;
expr_ref def1(m_manager), def2(m_manager);
app_ref head2(m_manager);
if (m_manager.is_ite(n, c, t, e) &&
is_ite_macro(t, num_decls, head, def1) &&
is_ite_macro(e, num_decls, head2, def2) && head == head2) {
def = m_manager.mk_ite(c, def1, def2);
return true;
}
return false;
}
/**
\brief Return true if n is of the form
@ -206,7 +222,7 @@ bool macro_util::is_left_simple_macro(expr * n, unsigned num_decls, app * & head
def will contain t
*/
bool macro_util::is_right_simple_macro(expr * n, unsigned num_decls, app * & head, expr * & def) const {
bool macro_util::is_right_simple_macro(expr * n, unsigned num_decls, app_ref & head, expr_ref & def) const {
if (m_manager.is_eq(n) || m_manager.is_iff(n)) {
expr * lhs = to_app(n)->get_arg(0);
expr * rhs = to_app(n)->get_arg(1);
@ -302,7 +318,7 @@ bool macro_util::is_arith_macro(expr * n, unsigned num_decls, app_ref & head, ex
/**
\brief Auxiliary function for is_pseudo_predicate_macro. It detects the pattern (= (f X) t)
*/
bool macro_util::is_pseudo_head(expr * n, unsigned num_decls, app * & head, app * & t) {
bool macro_util::is_pseudo_head(expr * n, unsigned num_decls, app_ref & head, app_ref & t) {
if (!m_manager.is_eq(n))
return false;
expr * lhs = to_app(n)->get_arg(0);
@ -332,7 +348,7 @@ bool macro_util::is_pseudo_head(expr * n, unsigned num_decls, app * & head, app
\brief Returns true if n if of the form (forall (X) (iff (= (f X) t) def[X]))
where t is a ground term, (f X) is the head.
*/
bool macro_util::is_pseudo_predicate_macro(expr * n, app * & head, app * & t, expr * & def) {
bool macro_util::is_pseudo_predicate_macro(expr * n, app_ref & head, app_ref & t, expr_ref & def) {
if (!is_quantifier(n) || !to_quantifier(n)->is_forall())
return false;
TRACE("macro_util", tout << "processing: " << mk_pp(n, m_manager) << "\n";);
@ -870,9 +886,8 @@ void macro_util::collect_arith_macro_candidates(expr * atom, unsigned num_decls,
THEN M'(atom) = true
*/
void macro_util::collect_macro_candidates_core(expr * atom, unsigned num_decls, macro_candidates & r) {
if (m_manager.is_eq(atom) || m_manager.is_iff(atom)) {
expr * lhs = to_app(atom)->get_arg(0);
expr * rhs = to_app(atom)->get_arg(1);
expr* lhs, *rhs;
if (m_manager.is_eq(atom, lhs, rhs) || m_manager.is_iff(atom, lhs, rhs)) {
if (is_quasi_macro_head(lhs, num_decls) &&
!is_forbidden(to_app(lhs)->get_decl()) &&
!occurs(to_app(lhs)->get_decl(), rhs) &&
@ -884,7 +899,6 @@ void macro_util::collect_macro_candidates_core(expr * atom, unsigned num_decls,
else if (is_hint_atom(lhs, rhs)) {
insert_quasi_macro(to_app(lhs), num_decls, rhs, 0, false, true, true, r);
}
if (is_quasi_macro_head(rhs, num_decls) &&
!is_forbidden(to_app(rhs)->get_decl()) &&

11
src/ast/macros/macro_util.h
View file

@ -102,11 +102,12 @@ public:
basic_simplifier_plugin * get_basic_simp() const;
bool is_macro_head(expr * n, unsigned num_decls) const;
bool is_left_simple_macro(expr * n, unsigned num_decls, app * & head, expr * & def) const;
bool is_right_simple_macro(expr * n, unsigned num_decls, app * & head, expr * & def) const;
bool is_simple_macro(expr * n, unsigned num_decls, app * & head, expr * & def) const {
bool is_left_simple_macro(expr * n, unsigned num_decls, app_ref & head, expr_ref & def) const;
bool is_right_simple_macro(expr * n, unsigned num_decls, app_ref & head, expr_ref & def) const;
bool is_simple_macro(expr * n, unsigned num_decls, app_ref& head, expr_ref & def) const {
return is_left_simple_macro(n, num_decls, head, def) || is_right_simple_macro(n, num_decls, head, def);
}
bool is_ite_macro(expr * n, unsigned num_decls, app_ref& head, expr_ref& def) const;
bool is_arith_macro(expr * n, unsigned num_decls, app_ref & head, expr_ref & def, bool & inv) const;
bool is_arith_macro(expr * n, unsigned num_decls, app_ref & head, expr_ref & def) const {
@ -114,8 +115,8 @@ public:
return is_arith_macro(n, num_decls, head, def, inv);
}
bool is_pseudo_head(expr * n, unsigned num_decls, app * & head, app * & t);
bool is_pseudo_predicate_macro(expr * n, app * & head, app * & t, expr * & def);
bool is_pseudo_head(expr * n, unsigned num_decls, app_ref & head, app_ref & t);
bool is_pseudo_predicate_macro(expr * n, app_ref & head, app_ref & t, expr_ref & def);
bool is_quasi_macro_head(expr * n, unsigned num_decls) const;
void quasi_macro_head_to_macro_head(app * qhead, unsigned num_decls, app_ref & head, expr_ref & cond) const;

18
src/nlsat/tactic/nlsat_tactic.cpp
View file

@ -25,6 +25,7 @@ Notes:
#include"ast_smt2_pp.h"
#include"z3_exception.h"
#include"algebraic_numbers.h"
#include"ast_pp.h"
class nlsat_tactic : public tactic {
struct expr_display_var_proc : public nlsat::display_var_proc {
@ -78,9 +79,21 @@ class nlsat_tactic : public tactic {
}
return false;
}
bool eval_model(model& model, goal& g) {
unsigned sz = g.size();
for (unsigned i = 0; i < sz; i++) {
expr_ref val(m);
if (model.eval(g.form(i), val) && !m.is_true(val)) {
TRACE("nlsat", tout << mk_pp(g.form(i), m) << " -> " << val << "\n";);
return false;
}
}
return true;
}
// Return false if nlsat assigned noninteger value to an integer variable.
bool mk_model(expr_ref_vector & b2a, expr_ref_vector & x2t, model_converter_ref & mc) {
bool mk_model(goal & g, expr_ref_vector & b2a, expr_ref_vector & x2t, model_converter_ref & mc) {
bool ok = true;
model_ref md = alloc(model, m);
arith_util util(m);
@ -110,6 +123,7 @@ class nlsat_tactic : public tactic {
continue; // don't care
md->register_decl(to_app(a)->get_decl(), val == l_true ? m.mk_true() : m.mk_false());
}
DEBUG_CODE(eval_model(*md.get(), g););
mc = model2model_converter(md.get());
return ok;
}
@ -151,7 +165,7 @@ class nlsat_tactic : public tactic {
if (!contains_unsupported(b2a, x2t)) {
// If mk_model is false it means that the model produced by nlsat
// assigns noninteger values to integer variables
if (mk_model(b2a, x2t, mc)) {
if (mk_model(*g.get(), b2a, x2t, mc)) {
// result goal is trivially SAT
g->reset();
}

27
src/smt/theory_arith_core.h
View file

@ -1235,6 +1235,14 @@ namespace smt {
ctx.set_var_theory(bv, get_id());
rational _k;
VERIFY(m_util.is_numeral(rhs, _k));
if (is_int(v) && !_k.is_int()) {
if (kind == A_UPPER) {
_k = floor(_k);
}
else {
_k = ceil(_k);
}
}
inf_numeral k(_k);
atom * a = alloc(atom, bv, v, k, kind);
mk_bound_axioms(a);
@ -1399,22 +1407,22 @@ namespace smt {
final_check_status result = FC_DONE;
final_check_status ok;
do {
TRACE("final_check_arith", tout << "m_final_check_idx: " << m_final_check_idx << ", result: " << result << "\n";);
TRACE("arith", tout << "m_final_check_idx: " << m_final_check_idx << ", result: " << result << "\n";);
switch (m_final_check_idx) {
case 0:
ok = check_int_feasibility();
TRACE("final_check_arith", tout << "check_int_feasibility(), ok: " << ok << "\n";);
TRACE("arith", tout << "check_int_feasibility(), ok: " << ok << "\n";);
break;
case 1:
if (assume_eqs_core())
ok = FC_CONTINUE;
else
ok = FC_DONE;
TRACE("final_check_arith", tout << "assume_eqs(), ok: " << ok << "\n";);
TRACE("arith", tout << "assume_eqs(), ok: " << ok << "\n";);
break;
default:
ok = process_non_linear();
TRACE("final_check_arith", tout << "non_linear(), ok: " << ok << "\n";);
TRACE("arith", tout << "non_linear(), ok: " << ok << "\n";);
break;
}
m_final_check_idx = (m_final_check_idx + 1) % 3;
@ -1425,7 +1433,7 @@ namespace smt {
result = FC_GIVEUP;
break;
case FC_CONTINUE:
TRACE("final_check_arith",
TRACE("arith",
tout << "continue arith..."
<< (get_context().inconsistent()?"inconsistent\n":"\n"););
return FC_CONTINUE;
@ -1442,7 +1450,7 @@ namespace smt {
template<typename Ext>
final_check_status theory_arith<Ext>::final_check_eh() {
TRACE("arith_eq_adapter_info", m_arith_eq_adapter.display_already_processed(tout););
TRACE("arith_final_check", display(tout););
TRACE("arith", display(tout););
if (!propagate_core())
return FC_CONTINUE;
@ -1459,7 +1467,7 @@ namespace smt {
m_liberal_final_check = false;
m_changed_assignment = false;
result = final_check_core();
TRACE("final_check_arith", tout << "result: " << result << "\n";);
TRACE("arith", tout << "result: " << result << "\n";);
return result;
}
@ -2416,6 +2424,7 @@ namespace smt {
theory_var v = b->get_var();
inf_numeral const & k = b->get_value();
TRACE("arith", display_bound(tout, b); tout << "v" << v << " <= " << k << "\n";);
bound * u = upper(v);
bound * l = lower(v);
@ -2456,7 +2465,7 @@ namespace smt {
template<typename Ext>
bool theory_arith<Ext>::assert_bound(bound * b) {
TRACE("assert_bound", display_bound(tout, b););
TRACE("assert_bound", display_bound(tout, b); display(tout););
theory_var v = b->get_var();
if (b->is_atom()) {
@ -2478,7 +2487,7 @@ namespace smt {
break;
}
TRACE("arith_assert", tout << "result: " << result << "\n"; display(tout););
TRACE("arith_bound", tout << "result: " << result << "\n"; display(tout););
return result;
}

4
src/smt/theory_arith_int.h
View file

@ -1267,11 +1267,11 @@ namespace smt {
final_check_status theory_arith<Ext>::check_int_feasibility() {
TRACE("arith_int_detail", get_context().display(tout););
if (!has_infeasible_int_var()) {
TRACE("arith_int_incomp", tout << "FC_DONE 1...\n"; display(tout););
TRACE("arith", tout << "FC_DONE 1...\n"; display(tout););
return FC_DONE;
}
TRACE("arith_int_fracs",
TRACE("arith",
int num = get_num_vars();
for (theory_var v = 0; v < num; v++) {
if (is_int(v) && !get_value(v).is_int()) {

9
src/tactic/arith/purify_arith_tactic.cpp
View file

@ -378,12 +378,13 @@ struct purify_arith_proc {
cache_result(t, result, result_pr);
expr * x = args[0];
// to-real(k) - x >= 0
expr * diff = u().mk_add(u().mk_to_real(k), u().mk_mul(u().mk_numeral(rational(-1), false), x));
// x - to-real(k) >= 0
expr * diff = u().mk_add(x, u().mk_mul(u().mk_numeral(rational(-1), false), u().mk_to_real(k)));
push_cnstr(u().mk_ge(diff, mk_real_zero()));
push_cnstr_pr(result_pr);
// not(to-real(k) - x >= 1)
// not(x - to-real(k) >= 1)
push_cnstr(NOT(u().mk_ge(diff, u().mk_numeral(rational(1), false))));
push_cnstr_pr(result_pr);
}
@ -757,6 +758,7 @@ struct purify_arith_proc {
// add cnstraints
sz = r.cfg().m_new_cnstrs.size();
TRACE("purify_arith", tout << r.cfg().m_new_cnstrs << "\n";);
for (unsigned i = 0; i < sz; i++) {
m_goal.assert_expr(r.cfg().m_new_cnstrs.get(i), m_produce_proofs ? r.cfg().m_new_cnstr_prs.get(i) : 0, 0);
}
@ -827,6 +829,7 @@ public:
SASSERT(g->is_well_sorted());
mc = 0; pc = 0; core = 0;
tactic_report report("purify-arith", *g);
TRACE("purify_arith", g->display(tout););
bool produce_proofs = g->proofs_enabled();
bool produce_models = g->models_enabled();
bool elim_root_objs = m_params.get_bool("elim_root_objects", true);