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fill out qe_solve_plugin functionality

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2018-06-11 18:30:36 -07:00 • committed by Arie Gurfinkel
parent e226b39914
commit 7714d05c1a
5 changed files with 144 additions and 163 deletions
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169
src/qe/qe_lite.cpp
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@ -36,6 +36,7 @@ Revision History:
#include "ast/datatype_decl_plugin.h"
#include "qe/qe_vartest.h"
#include "qe/qe_solve_plugin.h"
namespace eq {
@ -72,6 +73,7 @@ namespace eq {
beta_reducer m_subst;
expr_ref_vector m_subst_map;
expr_ref_vector m_new_exprs;
plugin_manager<qe::solve_plugin> m_solvers;
ptr_vector<expr> m_map;
int_vector m_pos2var;
@ -221,97 +223,6 @@ namespace eq {
}
}
bool is_invertible_const(bool is_int, expr* x, rational& a_val) {
expr* y;
if (a.is_uminus(x, y) && is_invertible_const(is_int, y, a_val)) {
a_val.neg();
return true;
}
else if (a.is_numeral(x, a_val) && !a_val.is_zero()) {
if (!is_int || a_val.is_one() || a_val.is_minus_one()) {
return true;
}
}
return false;
}
bool is_invertible_mul(bool is_int, expr*& arg, rational& a_val) {
if (is_variable(arg)) {
a_val = rational(1);
return true;
}
expr* x, *y;
if (a.is_mul(arg, x, y)) {
if (is_variable(x) && is_invertible_const(is_int, y, a_val)) {
arg = x;
return true;
}
if (is_variable(y) && is_invertible_const(is_int, x, a_val)) {
arg = y;
return true;
}
}
return false;
}
typedef std::pair<bool,expr*> signed_expr;
expr_ref solve_arith(bool is_int, rational const& r, bool sign, svector<signed_expr> const& exprs) {
expr_ref_vector result(m);
for (unsigned i = 0; i < exprs.size(); ++i) {
bool sign2 = exprs[i].first;
expr* e = exprs[i].second;
rational r2(r);
if (sign == sign2) {
r2.neg();
}
if (!r2.is_one()) {
result.push_back(a.mk_mul(a.mk_numeral(r2, is_int), e));
}
else {
result.push_back(e);
}
}
return expr_ref(a.mk_add(result.size(), result.c_ptr()), m);
}
bool solve_arith(expr* lhs, expr* rhs, ptr_vector<var>& vs, expr_ref_vector& ts) {
if (!a.is_int(lhs) && !a.is_real(rhs)) {
return false;
}
rational a_val;
bool is_int = a.is_int(lhs);
svector<signed_expr> todo, done;
todo.push_back(std::make_pair(true, lhs));
todo.push_back(std::make_pair(false, rhs));
while (!todo.empty()) {
expr* e = todo.back().second;
bool sign = todo.back().first;
todo.pop_back();
if (a.is_add(e)) {
for (unsigned i = 0; i < to_app(e)->get_num_args(); ++i) {
todo.push_back(std::make_pair(sign, to_app(e)->get_arg(i)));
}
}
else if (is_invertible_mul(is_int, e, a_val)) {
done.append(todo);
vs.push_back(to_var(e));
a_val = rational(1)/a_val;
ts.push_back(solve_arith(is_int, a_val, sign, done));
TRACE("qe_lite", tout << mk_pp(lhs, m) << " " << mk_pp(rhs, m) << " " << mk_pp(e, m) << " := " << mk_pp(ts.back(), m) << "\n";);
return true;
}
else {
done.push_back(std::make_pair(sign, e));
}
}
return false;
}
bool arith_solve(expr * lhs, expr * rhs, expr * eq, ptr_vector<var>& vs, expr_ref_vector& ts) {
return solve_arith(lhs, rhs, vs, ts);
}
bool trivial_solve(expr* lhs, expr* rhs, expr* eq, ptr_vector<var>& vs, expr_ref_vector& ts) {
if (!is_variable(lhs)) {
std::swap(lhs, rhs);
@ -343,65 +254,25 @@ namespace eq {
*/
bool is_var_eq(expr * e, ptr_vector<var>& vs, expr_ref_vector & ts) {
expr* lhs, *rhs;
var* v;
expr* lhs = nullptr, *rhs = nullptr;
// (= VAR t), (iff VAR t), (iff (not VAR) t), (iff t (not VAR)) cases
if (m.is_eq(e, lhs, rhs) && trivial_solve(lhs, rhs, e, vs, ts)) {
return true;
}
family_id fid = get_sort(e)->get_family_id();
if (m.is_eq(e, lhs, rhs)) {
// (iff (not VAR) t) (iff t (not VAR)) cases
if (!is_variable(lhs) && !is_variable(rhs) && m.is_bool(lhs)) {
if (!is_neg_var(m, lhs, v)) {
std::swap(lhs, rhs);
}
if (!is_neg_var(m, lhs, v)) {
return false;
}
vs.push_back(v);
ts.push_back(m.mk_not(rhs));
TRACE("qe_lite", tout << mk_pp(e, m) << "\n";);
fid = get_sort(lhs)->get_family_id();
}
qe::solve_plugin* p = m_solvers.get_plugin(fid);
if (p) {
expr_ref res = (*p)(e);
if (res != e && m.is_eq(res, lhs, rhs) && is_variable(lhs)) {
vs.push_back(to_var(lhs));
ts.push_back(rhs);
return true;
}
if (trivial_solve(lhs, rhs, e, vs, ts)) {
return true;
}
if (arith_solve(lhs, rhs, e, vs, ts)) {
return true;
}
return false;
}
// (ite cond (= VAR t) (= VAR t2)) case
expr* cond, *e2, *e3;
if (m.is_ite(e, cond, e2, e3)) {
if (is_var_eq(e2, vs, ts)) {
expr_ref_vector ts2(m);
ptr_vector<var> vs2;
if (is_var_eq(e3, vs2, ts2) && same_vars(vs, vs2)) {
for (unsigned i = 0; i < vs.size(); ++i) {
ts[i] = m.mk_ite(cond, ts[i].get(), ts2[i].get());
}
return true;
}
}
return false;
}
// VAR = true case
if (is_variable(e)) {
ts.push_back(m.mk_true());
vs.push_back(to_var(e));
TRACE("qe_lite", tout << mk_pp(e, m) << "\n";);
return true;
}
// VAR = false case
if (is_neg_var(m, e, v)) {
ts.push_back(m.mk_false());
vs.push_back(v);
TRACE("qe_lite", tout << mk_pp(e, m) << "\n";);
return true;
}
return false;
}
@ -785,9 +656,15 @@ namespace eq {
m_new_exprs(m),
m_new_args(m),
m_rewriter(m),
m_params(p) {}
m_params(p) {
}
void set_is_variable_proc(is_variable_proc& proc) { m_is_variable = &proc;}
void set_is_variable_proc(is_variable_proc& proc) {
m_is_variable = &proc;
m_solvers.reset();
m_solvers.register_plugin(qe::mk_arith_solve_plugin(m, proc));
m_solvers.register_plugin(qe::mk_basic_solve_plugin(m, proc));
}
void operator()(quantifier * q, expr_ref & r, proof_ref & pr) {
TRACE("qe_lite", tout << mk_pp(q, m) << "\n";);