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adding argument restriction to mbqi, fix tracking of m_src/m_dst for expr_safe_replace and avoid resetting the cache.

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This commit is contained in:
Nikolaj Bjorner 2020-10-27 11:41:45 -07:00
parent 24321e311b
commit e2fbd05fe7
6 changed files with 159 additions and 58 deletions
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102
src/sat/smt/q_mbi.cpp
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@ -17,6 +17,7 @@ Author:
#include "ast/ast_trail.h"
#include "ast/ast_util.h"
#include "ast/for_each_expr.h"
#include "ast/rewriter/var_subst.h"
#include "ast/rewriter/expr_safe_replace.h"
#include "qe/mbp/mbp_arith.h"
@ -98,7 +99,6 @@ namespace q {
}
lbool mbqi::check_forall(quantifier* q) {
quantifier* q_flat = m_qs.flatten(q);
auto* qb = specialize(q_flat);
if (!qb)
@ -113,18 +113,33 @@ namespace q {
return r;
if (r == l_false)
return l_true;
model_ref mdl0;
model_ref mdl0, mdl1;
expr_ref proj(m);
m_solver->get_model(mdl0);
expr_ref proj = solver_project(*mdl0, *qb);
if (!proj)
return l_undef;
sat::literal qlit = ctx.expr2literal(q);
if (is_exists(q))
qlit.neg();
ctx.get_rewriter()(proj);
TRACE("q", tout << proj << "\n";);
// TODO: add as top-level clause for relevancy
m_qs.add_clause(~qlit, ~ctx.mk_literal(proj));
unsigned i = 0;
{
::solver::scoped_push _sp(*m_solver);
restrict_domains(*mdl0, *qb);
for (; i < m_max_cex && l_true == m_solver->check_sat(0, nullptr); ++i) {
m_solver->get_model(mdl1);
proj = solver_project(*mdl1, *qb);
if (!proj)
break;
m_qs.add_clause(~qlit, ~ctx.mk_literal(proj));
m_solver->assert_expr(m.mk_not(proj));
}
}
if (i == 0) {
qb->domain_eqs.reset();
proj = solver_project(*mdl0, *qb);
if (!proj)
return l_undef;
m_qs.add_clause(~qlit, ~ctx.mk_literal(proj));
}
// TODO: add as top-level clause for relevancy
return l_false;
}
@ -146,6 +161,7 @@ namespace q {
restrict_to_universe(vars.get(i), m_model->get_universe(s));
}
expr_ref fml = subst(q->get_expr(), vars);
extract_var_args(q->get_expr(), *result);
if (is_forall(q))
fml = m.mk_not(fml);
flatten_and(fml, result->vbody);
@ -189,12 +205,13 @@ namespace q {
for (app* v : qb.vars)
m_model->register_decl(v->get_decl(), mdl(v));
TRACE("q",
tout << "Project\n";
tout << *m_model << "\n";
tout << qb.vbody << "\n";
tout << "model of projection\n" << mdl << "\n";);
tout << "Project\n";
tout << *m_model << "\n";
tout << qb.vbody << "\n";
tout << "model of projection\n" << mdl << "\n";);
expr_ref_vector fmls(qb.vbody);
app_ref_vector vars(qb.vars);
fmls.append(qb.domain_eqs);
mbp::project_plugin proj(m);
proj.purify(m_model_fixer, *m_model, vars, fmls);
for (unsigned i = 0; i < vars.size(); ++i) {
@ -203,19 +220,60 @@ namespace q {
if (p)
(*p)(*m_model, vars, fmls);
}
if (!vars.empty()) {
expr_safe_replace esubst(m);
for (app* v : vars) {
expr_ref val = assign_value(*m_model, v);
if (!val)
return expr_ref(m);
esubst.insert(v, val);
}
esubst(fmls);
expr_safe_replace esubst(m);
for (app* v : qb.vars) {
expr_ref val = assign_value(*m_model, v);
if (!val)
return expr_ref(m);
esubst.insert(v, val);
}
esubst(fmls);
return mk_and(fmls);
}
/**
* Add disjunctions to m_solver that restrict the possible values of
* arguments to uninterpreted functions. The disjunctions added to the solver
* are specialized with respect to m_model.
* Add also disjunctions to the quantifier "domain_eqs", to track the constraints
* added to the solver.
*/
void mbqi::restrict_domains(model& mdl, q_body& qb) {
qb.domain_eqs.reset();
var_subst subst(m);
for (auto p : qb.var_args) {
expr_ref bounds = m_model_fixer.restrict_arg(p.first, p.second);
if (m.is_true(bounds))
continue;
expr_ref vbounds = subst(bounds, qb.vars);
expr_ref mbounds(m);
if (!m_model->eval_expr(bounds, mbounds, true))
return;
mbounds = subst(mbounds, qb.vars);
std::cout << "restrict with bounds " << mbounds << " " << vbounds << "\n";
m_solver->assert_expr(mbounds);
qb.domain_eqs.push_back(vbounds);
}
}
/*
* Add domain restrictions for every non-ground arguments to uninterpreted functions.
*/
void mbqi::extract_var_args(expr* _t, q_body& qb) {
expr_ref t(_t, m);
for (expr* s : subterms(t)) {
if (is_ground(s))
continue;
if (is_uninterp(s) && to_app(s)->get_num_args() > 0) {
app* a = to_app(s);
for (unsigned i = 0; i < a->get_num_args(); ++i) {
if (is_ground(a->get_arg(i)))
qb.var_args.push_back(std::make_pair(a, i));
}
}
}
}
expr_ref mbqi::assign_value(model& mdl, app* v) {
func_decl* f = v->get_decl();
expr_ref val(mdl.get_some_const_interp(f), m);