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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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2
src/ast/datatype_decl_plugin.h
View file

@ -358,8 +358,10 @@ namespace datatype {
bool is_accessor(func_decl * f) const { return is_decl_of(f, m_family_id, OP_DT_ACCESSOR); }
bool is_update_field(func_decl * f) const { return is_decl_of(f, m_family_id, OP_DT_UPDATE_FIELD); }
bool is_constructor(app * f) const { return is_app_of(f, m_family_id, OP_DT_CONSTRUCTOR); }
bool is_constructor(expr* e) const { return is_app(e) && is_constructor(to_app(e)); }
bool is_recognizer0(app * f) const { return is_app_of(f, m_family_id, OP_DT_RECOGNISER);}
bool is_is(app * f) const { return is_app_of(f, m_family_id, OP_DT_IS);}
bool is_is(expr * e) const { return is_app(e) && is_is(to_app(e)); }
bool is_recognizer(app * f) const { return is_recognizer0(f) || is_is(f); }
bool is_accessor(app * f) const { return is_app_of(f, m_family_id, OP_DT_ACCESSOR); }
bool is_update_field(app * f) const { return is_app_of(f, m_family_id, OP_DT_UPDATE_FIELD); }

169
src/qe/qe_lite.cpp
View file

@ -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";);

125
src/qe/qe_solve_plugin.cpp
View file

@ -19,6 +19,7 @@ Revision History:
--*/
#include "ast/arith_decl_plugin.h"
#include "ast/datatype_decl_plugin.h"
#include "ast/ast_util.h"
#include "ast/ast_pp.h"
#include "qe/qe_solve_plugin.h"
@ -65,7 +66,7 @@ namespace qe {
/**
* \brief return true if lhs = rhs can be solved as v = t, where v is a variable.
*/
bool solve_arith(expr* lhs, expr* rhs, expr_ref& v, expr_ref& t) {
bool solve(expr* lhs, expr* rhs, expr_ref& v, expr_ref& t) {
if (!a.is_int(lhs) && !a.is_real(rhs)) {
return false;
}
@ -83,6 +84,16 @@ namespace qe {
todo.push_back(std::make_pair(sign, e));
}
}
else if (a.is_sub(e)) {
app* sub = to_app(e);
todo.push_back(std::make_pair(sign, sub->get_arg(0)));
for (unsigned i = 1; i < sub->get_num_args(); ++i) {
todo.push_back(std::make_pair(!sign, sub->get_arg(i)));
}
}
else if (a.is_uminus(e)) {
todo.push_back(std::make_pair(!sign, to_app(e)->get_arg(0)));
}
else if (is_invertible_mul(is_int, e, a_val)) {
done.append(todo);
v = e;
@ -98,7 +109,7 @@ namespace qe {
return false;
}
// can we solve for a variable by ...
// is x a constant and can we safely divide by x to solve for a variable?
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)) {
@ -113,6 +124,8 @@ namespace qe {
return false;
}
// is arg of the form a_val * v, where a_val
// is a constant that we can safely divide by.
bool is_invertible_mul(bool is_int, expr*& arg, rational& a_val) {
if (is_variable(arg)) {
a_val = rational(1);
@ -133,10 +146,11 @@ namespace qe {
}
expr_ref mk_eq_core (expr *_e1, expr *_e2) {
expr *e1, *e2;
e1 = _e1;
e2 = _e2;
expr_ref mk_eq_core (expr *e1, expr *e2) {
expr_ref v(m), t(m);
if (solve(e1, e2, v, t)) {
return expr_ref(m.mk_eq(v, t), m);
}
if (a.is_zero(e1)) {
std::swap(e1, e2);
@ -257,6 +271,90 @@ namespace qe {
}
};
class basic_solve_plugin : public solve_plugin {
public:
basic_solve_plugin(ast_manager& m, is_variable_proc& is_var):
solve_plugin(m, m.get_basic_family_id(), is_var) {}
expr_ref solve(expr *atom, bool is_pos) override {
expr_ref res(atom, m);
expr* lhs = nullptr, *rhs = nullptr, *n = nullptr;
if (m.is_eq(atom, lhs, rhs)) {
if (m.is_not(lhs, n) && is_variable(n)) {
res = m.mk_eq(n, mk_not(m, rhs));
}
else if (m.is_not(rhs, n) && is_variable(n)) {
res = m.mk_eq(n, mk_not(m, lhs));
}
else if (is_variable(rhs) && !is_variable(lhs)) {
res = m.mk_eq(rhs, lhs);
}
}
// (ite cond (= VAR t) (= VAR t2)) case
expr* cond = nullptr, *th = nullptr, *el = nullptr;
if (m.is_ite(atom, cond, th, el)) {
expr_ref r1 = solve(th, true);
expr_ref r2 = solve(el, true);
expr* v1 = nullptr, *t1 = nullptr, *v2 = nullptr, *t2 = nullptr;
if (m.is_eq(r1, v1, t1) && m.is_eq(r2, v2, t2) && v1 == v2) {
res = m.mk_eq(v1, m.mk_ite(cond, t1, t2));
}
}
if (is_variable(atom) && m.is_bool(atom)) {
res = m.mk_eq(atom, m.mk_bool_val(is_pos));
return res;
}
return is_pos ? res : mk_not(res);
}
};
class dt_solve_plugin : public solve_plugin {
datatype_util dt;
public:
dt_solve_plugin(ast_manager& m, is_variable_proc& is_var):
solve_plugin(m, m.get_family_id("datatype"), is_var),
dt(m) {}
expr_ref solve(expr *atom, bool is_pos) override {
expr_ref res(atom, m);
expr* lhs = nullptr, *rhs = nullptr;
if (m.is_eq(atom, lhs, rhs)) {
if (dt.is_constructor(rhs)) {
std::swap(lhs, rhs);
}
if (dt.is_constructor(lhs) && dt.is_constructor(rhs)) {
app* l = to_app(lhs), *r = to_app(rhs);
if (l->get_decl() == r->get_decl()) {
expr_ref_vector eqs(m);
for (unsigned i = 0, sz = l->get_num_args(); i < sz; ++i) {
eqs.push_back(m.mk_eq(l->get_arg(i), r->get_arg(i)));
}
res = mk_and(eqs);
}
else {
res = m.mk_false();
}
}
else if (dt.is_constructor(lhs)) {
app* l = to_app(lhs);
func_decl* d = l->get_decl();
expr_ref_vector conjs(m);
conjs.push_back(dt.mk_is(d, rhs));
ptr_vector<func_decl> const& acc = *dt.get_constructor_accessors(d);
for (unsigned i = 0; i < acc.size(); ++i) {
conjs.push_back(m.mk_eq(l->get_arg(i), m.mk_app(acc[i], rhs)));
}
res = mk_and(conjs);
}
}
// TBD: can also solve for is_nil(x) by x = nil
//
return is_pos ? res : mk_not(res);
}
};
class bv_solve_plugin : public solve_plugin {
public:
bv_solve_plugin(ast_manager& m, is_variable_proc& is_var): solve_plugin(m, m.get_family_id("bv"), is_var) {}
@ -266,15 +364,6 @@ namespace qe {
}
};
class dt_solve_plugin : public solve_plugin {
public:
dt_solve_plugin(ast_manager& m, is_variable_proc& is_var): solve_plugin(m, m.get_family_id("dt"), is_var) {}
expr_ref solve(expr *atom, bool is_pos) override {
expr_ref res(atom, m);
return is_pos ? res : mk_not(res);
}
};
class array_solve_plugin : public solve_plugin {
public:
array_solve_plugin(ast_manager& m, is_variable_proc& is_var): solve_plugin(m, m.get_family_id("array"), is_var) {}
@ -284,6 +373,9 @@ namespace qe {
}
};
solve_plugin* mk_basic_solve_plugin(ast_manager& m, is_variable_proc& is_var) {
return alloc(basic_solve_plugin, m, is_var);
}
solve_plugin* mk_arith_solve_plugin(ast_manager& m, is_variable_proc& is_var) {
return alloc(arith_solve_plugin, m, is_var);
@ -293,6 +385,7 @@ namespace qe {
return alloc(dt_solve_plugin, m, is_var);
}
#if 0
solve_plugin* mk_bv_solve_plugin(ast_manager& m, is_variable_proc& is_var) {
return alloc(bv_solve_plugin, m, is_var);
}
@ -300,4 +393,6 @@ namespace qe {
solve_plugin* mk_array_solve_plugin(ast_manager& m, is_variable_proc& is_var) {
return alloc(array_solve_plugin, m, is_var);
}
#endif
}

6
src/qe/qe_solve_plugin.h
View file

@ -42,11 +42,13 @@ namespace qe {
expr_ref operator() (expr *lit);
};
solve_plugin* mk_basic_solve_plugin(ast_manager& m, is_variable_proc& is_var);
solve_plugin* mk_arith_solve_plugin(ast_manager& m, is_variable_proc& is_var);
solve_plugin* mk_dt_solve_plugin(ast_manager& m, is_variable_proc& is_var);
solve_plugin* mk_bv_solve_plugin(ast_manager& m, is_variable_proc& is_var);
// solve_plugin* mk_bv_solve_plugin(ast_manager& m, is_variable_proc& is_var);
solve_plugin* mk_array_solve_plugin(ast_manager& m, is_variable_proc& is_var);
// solve_plugin* mk_array_solve_plugin(ast_manager& m, is_variable_proc& is_var);
}

5
src/util/plugin_manager.h
View file

@ -27,7 +27,12 @@ class plugin_manager {
ptr_vector<Plugin> m_plugins;
public:
~plugin_manager() {
reset();
}
void reset() {
std::for_each(m_plugins.begin(), m_plugins.end(), delete_proc<Plugin>());
release();
}
/**