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adding dt-solver (#4739)

* adding dt-solver

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* dt

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* move mbp to self-contained module

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* files

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* Create CMakeLists.txt

* dt

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* rename to bool_var2expr to indicate type class

* mbp

* na
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Nikolaj Bjorner 2020-10-18 15:28:21 -07:00 committed by GitHub
parent b77c57451f
commit 2f756da294
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62 changed files with 2309 additions and 1257 deletions

262
src/qe/mbp/mbp_plugin.cpp Normal file
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/*++
Copyright (c) 2015 Microsoft Corporation
Module Name:
qe_mbp.cpp
Abstract:
Model-based projection utilities
Author:
Nikolaj Bjorner (nbjorner) 2015-5-29
Revision History:
--*/
#include "ast/rewriter/expr_safe_replace.h"
#include "ast/ast_pp.h"
#include "ast/ast_util.h"
#include "ast/occurs.h"
#include "ast/rewriter/th_rewriter.h"
#include "ast/expr_functors.h"
#include "ast/for_each_expr.h"
#include "ast/scoped_proof.h"
#include "qe/mbp/mbp_plugin.h"
#include "model/model_pp.h"
#include "model/model_evaluator.h"
namespace mbp {
struct noop_op_proc {
void operator()(expr*) {}
};
void project_plugin::mark_rec(expr_mark& visited, expr* e) {
for_each_expr_proc<noop_op_proc> fe;
for_each_expr(fe, visited, e);
}
void project_plugin::mark_rec(expr_mark& visited, expr_ref_vector const& es) {
for (expr* e : es)
mark_rec(visited, e);
}
/**
\brief return two terms that are equal in the model.
The distinct term t is false in model, so there
are at least two arguments of t that are equal in the model.
*/
expr_ref project_plugin::pick_equality(ast_manager& m, model& model, expr* t) {
SASSERT(m.is_distinct(t));
expr_ref val(m);
expr_ref_vector vals(m);
obj_map<expr, expr*> val2expr;
app* alit = to_app(t);
if (alit->get_num_args() == 2) {
return expr_ref(m.mk_eq(alit->get_arg(0), alit->get_arg(1)), m);
}
for (expr* e1 : *alit) {
expr* e2;
val = model(e1);
TRACE("qe", tout << mk_pp(e1, m) << " |-> " << val << "\n";);
if (val2expr.find(val, e2)) {
return expr_ref(m.mk_eq(e1, e2), m);
}
val2expr.insert(val, e1);
vals.push_back(val);
}
for (unsigned i = 0; i < alit->get_num_args(); ++i) {
for (unsigned j = i + 1; j < alit->get_num_args(); ++j) {
expr* e1 = alit->get_arg(i);
expr* e2 = alit->get_arg(j);
val = m.mk_eq(e1, e2);
if (!model.is_false(val))
return expr_ref(m.mk_eq(e1, e2), m);
}
}
UNREACHABLE();
return expr_ref(nullptr, m);
}
void project_plugin::erase(expr_ref_vector& lits, unsigned& i) {
lits[i] = lits.back();
lits.pop_back();
--i;
}
void project_plugin::push_back(expr_ref_vector& lits, expr* e) {
if (!m.is_true(e))
lits.push_back(e);
}
void project_plugin::extract_literals(model& model, app_ref_vector const& vars, expr_ref_vector& fmls) {
m_bool_visited.reset();
expr_ref val(m);
model_evaluator eval(model);
eval.set_expand_array_equalities(true);
TRACE("qe", tout << fmls << "\n";);
for (unsigned i = 0; i < fmls.size(); ++i) {
expr* fml = fmls.get(i), * nfml, * f1, * f2, * f3;
SASSERT(m.is_bool(fml));
if (m.is_not(fml, nfml) && m.is_distinct(nfml))
fmls[i--] = mbp::project_plugin::pick_equality(m, model, nfml);
else if (m.is_or(fml)) {
for (expr* arg : *to_app(fml)) {
val = eval(arg);
if (m.is_true(val)) {
fmls[i] = arg;
--i;
break;
}
}
}
else if (m.is_and(fml)) {
fmls.append(to_app(fml)->get_num_args(), to_app(fml)->get_args());
mbp::project_plugin::erase(fmls, i);
}
else if (m.is_iff(fml, f1, f2) || (m.is_not(fml, nfml) && m.is_xor(nfml, f1, f2))) {
val = eval(f1);
if (m.is_false(val)) {
f1 = mk_not(m, f1);
f2 = mk_not(m, f2);
}
fmls[i--] = f1;
push_back(fmls, f2);
}
else if (m.is_implies(fml, f1, f2)) {
val = eval(f2);
if (m.is_true(val)) {
fmls[i] = f2;
}
else {
fmls[i] = mk_not(m, f1);
}
--i;
}
else if (m.is_ite(fml, f1, f2, f3)) {
val = eval(f1);
if (m.is_true(val)) {
push_back(fmls, f1);
push_back(fmls, f2);
}
else {
push_back(fmls, mk_not(m, f1));
push_back(fmls, f3);
}
mbp::project_plugin::erase(fmls, i);
}
else if (m.is_not(fml, nfml) && m.is_not(nfml, nfml)) {
push_back(fmls, nfml);
mbp::project_plugin::erase(fmls, i);
}
else if (m.is_not(fml, nfml) && m.is_and(nfml)) {
for (expr* arg : *to_app(nfml)) {
val = eval(arg);
if (m.is_false(val)) {
fmls[i--] = mk_not(m, arg);
break;
}
}
}
else if (m.is_not(fml, nfml) && m.is_or(nfml)) {
for (expr* arg : *to_app(nfml))
push_back(fmls, mk_not(m, arg));
mbp::project_plugin::erase(fmls, i);
}
else if ((m.is_not(fml, nfml) && m.is_iff(nfml, f1, f2)) || m.is_xor(fml, f1, f2)) {
val = eval(f1);
if (m.is_true(val)) {
f2 = mk_not(m, f2);
}
else {
f1 = mk_not(m, f1);
}
push_back(fmls, f1);
push_back(fmls, f2);
mbp::project_plugin::erase(fmls, i);
}
else if (m.is_not(fml, nfml) && m.is_implies(nfml, f1, f2)) {
push_back(fmls, f1);
push_back(fmls, mk_not(m, f2));
mbp::project_plugin::erase(fmls, i);
}
else if (m.is_not(fml, nfml) && m.is_ite(nfml, f1, f2, f3)) {
val = eval(f1);
if (m.is_true(val)) {
push_back(fmls, f1);
push_back(fmls, mk_not(m, f2));
}
else {
push_back(fmls, mk_not(m, f1));
push_back(fmls, mk_not(m, f3));
}
mbp::project_plugin::erase(fmls, i);
}
else if (m.is_not(fml, nfml)) {
if (extract_bools(eval, fmls, nfml)) {
mbp::project_plugin::erase(fmls, i);
}
}
else if (extract_bools(eval, fmls, fml))
mbp::project_plugin::erase(fmls, i);
}
TRACE("qe", tout << fmls << "\n";);
}
bool project_plugin::extract_bools(model_evaluator& eval, expr_ref_vector& fmls, expr* fml) {
TRACE("qe", tout << "extract bools: " << mk_pp(fml, m) << "\n";);
ptr_vector<expr> todo;
expr_safe_replace sub(m);
m_visited.reset();
bool found_bool = false;
if (is_app(fml)) {
todo.append(to_app(fml)->get_num_args(), to_app(fml)->get_args());
}
while (!todo.empty() && m.inc()) {
expr* e = todo.back();
todo.pop_back();
if (m_visited.is_marked(e)) {
continue;
}
m_visited.mark(e);
if (m.is_bool(e) && !m.is_true(e) && !m.is_false(e)) {
expr_ref val = eval(e);
TRACE("qe", tout << "found: " << mk_pp(e, m) << " " << val << "\n";);
if (!m.inc())
continue;
if (!m.is_true(val) && !m.is_false(val) && contains_uninterpreted(val))
throw default_exception("could not evaluate Boolean in model");
SASSERT(m.is_true(val) || m.is_false(val));
if (!m_bool_visited.is_marked(e))
fmls.push_back(m.is_true(val) ? e : mk_not(m, e));
sub.insert(e, val);
m_bool_visited.mark(e);
found_bool = true;
}
else if (is_app(e)) {
todo.append(to_app(e)->get_num_args(), to_app(e)->get_args());
}
else {
TRACE("qe", tout << "expression not handled " << mk_pp(e, m) << "\n";);
}
}
if (found_bool) {
expr_ref tmp(m);
sub(fml, tmp);
expr_ref val = eval(tmp);
if (!m.is_true(val) && !m.is_false(val))
return false;
fmls.push_back(m.is_true(val) ? tmp : mk_not(m, tmp));
}
return found_bool;
}
}