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z3/lib/theory_diff_logic_def.h
Leonardo de Moura e9eab22e5c Z3 sources
Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
2012-10-02 11:35:25 -07:00

1149 lines
34 KiB
C++

/*++
Copyright (c) 2006 Microsoft Corporation
Module Name:
theory_diff_logic_def.h
Abstract:
Difference Logic
Author:
Leonardo de Moura (leonardo) 2006-11-29.
Nikolaj Bjorner (nbjorner) 2008-05-11
Revision History:
2008-05-11 ported from v1.2. Add theory propagation.
--*/
#ifndef _THEORY_DIFF_LOGIC_DEF_H_
#define _THEORY_DIFF_LOGIC_DEF_H_
#include"theory_diff_logic.h"
#include"smt_context.h"
#include"map.h"
#include"ast_pp.h"
#include"warning.h"
#include"smt_model_generator.h"
using namespace smt;
template<typename Ext>
std::ostream& theory_diff_logic<Ext>::atom::display(theory_diff_logic const& th, std::ostream& out) const {
context& ctx = th.get_context();
lbool asgn = ctx.get_assignment(m_bvar);
//SASSERT(asgn == l_undef || ((asgn == l_true) == m_true));
bool sign = (l_undef == asgn) || m_true;
return out << literal(m_bvar, sign)
<< " " << mk_pp(ctx.bool_var2expr(m_bvar), th.get_manager()) << " ";
}
template<typename Ext>
std::ostream& theory_diff_logic<Ext>::eq_atom::display(theory_diff_logic const& th, std::ostream& out) const {
atom::display(th, out);
lbool asgn = th.get_context().get_assignment(this->m_bvar);
if (l_undef == asgn) {
out << "unassigned\n";
}
else {
out << mk_pp(m_le.get(), m_le.get_manager()) << " "
<< mk_pp(m_ge.get(), m_ge.get_manager()) << "\n";
}
return out;
}
template<typename Ext>
std::ostream& theory_diff_logic<Ext>::le_atom::display(theory_diff_logic const& th, std::ostream& out) const {
atom::display(th, out);
lbool asgn = th.get_context().get_assignment(this->m_bvar);
if (l_undef == asgn) {
out << "unassigned\n";
}
else {
th.m_graph.display_edge(out, get_asserted_edge());
}
return out;
}
// -----------------------------------------
// theory_diff_logic::nc_functor
template<typename Ext>
void theory_diff_logic<Ext>::nc_functor::reset() {
m_antecedents.reset();
}
// -----------------------------------------
// theory_diff_logic
template<typename Ext>
void theory_diff_logic<Ext>::init(context * ctx) {
theory::init(ctx);
app* zero;
enode* e;
zero = m_util.mk_numeral(rational(0), true);
e = ctx->mk_enode(zero, false, false, true);
SASSERT(!is_attached_to_var(e));
m_zero_int = mk_var(e);
zero = m_util.mk_numeral(rational(0), false);
e = ctx->mk_enode(zero, false, false, true);
SASSERT(!is_attached_to_var(e));
m_zero_real = mk_var(e);
}
template<typename Ext>
bool theory_diff_logic<Ext>::internalize_term(app * term) {
bool result = null_theory_var != mk_term(term);
CTRACE("arith", !result, tout << "Did not internalize " << mk_pp(term, get_manager()) << "\n";);
found_non_diff_logic_expr(term);
return result;
}
template<typename numeral>
class diff_logic_bounds {
bool m_inf_is_set;
bool m_sup_is_set;
bool m_eq_found;
literal m_inf_l;
literal m_sup_l;
literal m_eq_l;
numeral m_inf_w;
numeral m_sup_w;
numeral m_w;
public:
diff_logic_bounds() {
reset(numeral(0));
}
void reset(numeral const& w) {
m_inf_is_set = false;
m_sup_is_set = false;
m_eq_found = false;
m_inf_l = null_literal;
m_sup_l = null_literal;
m_eq_l = null_literal;
m_w = w;
}
void operator()(numeral const& w, literal l) {
if (l != null_literal) {
if ((w < m_w) && (!m_inf_is_set || w > m_inf_w)) {
m_inf_w = w;
m_inf_l = l;
m_inf_is_set = true;
}
else if ((w > m_w) && (!m_sup_is_set || w < m_sup_w)) {
m_sup_w = w;
m_sup_l = l;
m_sup_is_set = true;
}
else if (w == m_w) {
m_eq_found = true;
m_eq_l = l;
}
}
}
bool get_inf(numeral& w, literal& l) const {
w = m_inf_w;
l = m_inf_l;
return m_inf_is_set;
}
bool get_sup(numeral& w, literal& l) const {
w = m_sup_w;
l = m_sup_l;
return m_sup_is_set;
}
bool get_eq(literal& l) const {
l = m_eq_l;
return m_eq_found;
}
};
//
// Atoms are of the form x + -1*y <= k, or x + -1*y = k
//
template<typename Ext>
void theory_diff_logic<Ext>::found_non_diff_logic_expr(expr * n) {
if (!m_non_diff_logic_exprs) {
TRACE("non_diff_logic", tout << "found non diff logic expression:\n" << mk_pp(n, get_manager()) << "\n";);
get_context().push_trail(value_trail<context, bool>(m_non_diff_logic_exprs));
m_non_diff_logic_exprs = true;
}
}
template<typename Ext>
bool theory_diff_logic<Ext>::internalize_atom(app * n, bool gate_ctx) {
context & ctx = get_context();
if (!m_util.is_le(n) && !m_util.is_ge(n)) {
found_non_diff_logic_expr(n);
return false;
}
SASSERT(m_util.is_le(n) || m_util.is_ge(n));
SASSERT(!ctx.b_internalized(n));
bool_var bv;
rational kr;
app * x, *y, *z;
theory_var source, target; // target - source <= k
app * lhs = to_app(n->get_arg(0));
app * rhs = to_app(n->get_arg(1));
if (!m_util.is_numeral(rhs, kr)) {
found_non_diff_logic_expr(n);
return false;
}
numeral k(kr);
bool is_add = m_util.is_add(lhs) && lhs->get_num_args() == 2;
if (is_add) {
x = to_app(lhs->get_arg(0));
y = to_app(lhs->get_arg(1));
}
if (is_add && is_negative(x, z)) {
target = mk_var(y);
source = mk_var(z);
}
else if (is_add && is_negative(y, z)) {
target = mk_var(x);
source = mk_var(z);
}
else {
target = mk_var(lhs);
source = get_zero(lhs);
}
if (m_util.is_ge(n)) {
std::swap(target, source);
k.neg();
}
bv = ctx.mk_bool_var(n);
ctx.set_var_theory(bv, get_id());
literal l(bv);
//
// Create axioms for situations as:
// x - y <= 5 => x - y <= 7
//
if (m_params.m_arith_add_binary_bounds) {
literal l0;
numeral k0;
diff_logic_bounds<numeral> bounds;
bounds.reset(k);
m_graph.enumerate_edges(source, target, bounds);
if (bounds.get_eq(l0)) {
ctx.mk_th_axiom(get_id(),~l0,l);
ctx.mk_th_axiom(get_id(),~l,l0);
}
else {
if (bounds.get_inf(k0, l0)) {
SASSERT(k0 <= k);
ctx.mk_th_axiom(get_id(),~l0,l);
}
if (bounds.get_sup(k0, l0)) {
SASSERT(k <= k0);
ctx.mk_th_axiom(get_id(),~l,l0);
}
}
}
edge_id pos = m_graph.add_edge(source, target, k, l);
k.neg();
if (m_util.is_int(lhs)) {
SASSERT(k.is_int());
k -= numeral(1);
}
else {
m_is_lia = false;
k -= this->m_epsilon;
}
edge_id neg = m_graph.add_edge(target, source, k, ~l);
le_atom * a = alloc(le_atom, bv, pos, neg);
m_atoms.push_back(a);
m_bool_var2atom.insert(bv, a);
TRACE("arith",
tout << mk_pp(n, get_manager()) << "\n";
m_graph.display_edge(tout << "pos: ", pos);
m_graph.display_edge(tout << "neg: ", neg);
);
return true;
}
template<typename Ext>
void theory_diff_logic<Ext>::internalize_eq_eh(app * atom, bool_var v) {
context & ctx = get_context();
app * lhs = to_app(atom->get_arg(0));
app * rhs = to_app(atom->get_arg(1));
app * s;
if (m_util.is_add(lhs) && to_app(lhs)->get_num_args() == 2 &&
is_negative(to_app(to_app(lhs)->get_arg(1)), s) && m_util.is_numeral(rhs)) {
// force axioms for (= (+ x (* -1 y)) k)
// this is necessary because (+ x (* -1 y)) is not a diff logic term.
m_arith_eq_adapter.mk_axioms(ctx.get_enode(lhs), ctx.get_enode(rhs));
return;
}
if (m_params.m_arith_eager_eq_axioms) {
enode * n1 = ctx.get_enode(lhs);
enode * n2 = ctx.get_enode(rhs);
if (n1->get_th_var(get_id()) != null_theory_var &&
n2->get_th_var(get_id()) != null_theory_var)
m_arith_eq_adapter.mk_axioms(n1, n2);
}
}
template<typename Ext>
void theory_diff_logic<Ext>::assign_eh(bool_var v, bool is_true) {
m_stats.m_num_assertions++;
atom * a = 0;
m_bool_var2atom.find(v, a);
SASSERT(a);
SASSERT(get_context().get_assignment(v) != l_undef);
SASSERT((get_context().get_assignment(v) == l_true) == is_true);
a->assign_eh(is_true);
m_asserted_atoms.push_back(a);
}
template<typename Ext>
void theory_diff_logic<Ext>::collect_statistics(::statistics & st) const {
st.update("dl conflicts", m_stats.m_num_conflicts);
st.update("dl propagations", m_stats.m_num_th2core_prop);
st.update("dl asserts", m_stats.m_num_assertions);
st.update("core->dl eqs", m_stats.m_num_core2th_eqs);
m_arith_eq_adapter.collect_statistics(st);
}
template<typename Ext>
void theory_diff_logic<Ext>::push_scope_eh() {
theory::push_scope_eh();
m_graph.push();
m_scopes.push_back(scope());
scope & s = m_scopes.back();
s.m_atoms_lim = m_atoms.size();
s.m_asserted_atoms_lim = m_asserted_atoms.size();
s.m_asserted_qhead_old = m_asserted_qhead;
}
template<typename Ext>
void theory_diff_logic<Ext>::pop_scope_eh(unsigned num_scopes) {
unsigned lvl = m_scopes.size();
SASSERT(num_scopes <= lvl);
unsigned new_lvl = lvl - num_scopes;
scope & s = m_scopes[new_lvl];
del_atoms(s.m_atoms_lim);
m_asserted_atoms.shrink(s.m_asserted_atoms_lim);
m_asserted_qhead = s.m_asserted_qhead_old;
m_scopes.shrink(new_lvl);
m_graph.pop(num_scopes);
theory::pop_scope_eh(num_scopes);
}
template<typename Ext>
final_check_status theory_diff_logic<Ext>::final_check_eh() {
if (can_propagate()) {
propagate_core();
return FC_CONTINUE;
}
TRACE("arith_final", display(tout); );
// either will already be zero (as we don't do mixed constraints).
m_graph.set_to_zero(m_zero_int, m_zero_real);
SASSERT(is_consistent());
#if 0
TBD:
if (propagate_cheap_equalities()) {
return FC_CONTINUE;
}
#endif
if (m_non_diff_logic_exprs) {
return FC_GIVEUP;
}
return FC_DONE;
}
template<typename Ext>
void theory_diff_logic<Ext>::del_atoms(unsigned old_size) {
typename atoms::iterator begin = m_atoms.begin() + old_size;
typename atoms::iterator it = m_atoms.end();
while (it != begin) {
--it;
atom * a = *it;
bool_var bv = a->get_bool_var();
m_bool_var2atom.erase(bv);
dealloc(a);
}
m_atoms.shrink(old_size);
}
template<typename Ext>
bool theory_diff_logic<Ext>::is_negative(app* n, app*& m) {
if (!m_util.is_mul(n) || n->get_num_args() != 2) {
return false;
}
rational r;
expr* a0 = n->get_arg(0);
expr* a1 = n->get_arg(1);
if (m_util.is_numeral(a0, r) && r.is_minus_one() && is_app(a1)) {
m = to_app(a1);
return true;
}
if (m_util.is_numeral(a1, r) && r.is_minus_one() && is_app(a0)) {
m = to_app(a0);
return true;
}
return false;
}
template<typename Ext>
void theory_diff_logic<Ext>::propagate() {
if (m_params.m_arith_adaptive) {
switch(m_params.m_arith_propagation_strategy) {
case ARITH_PROP_PROPORTIONAL: {
++m_num_propagation_calls;
if (m_num_propagation_calls * (m_stats.m_num_conflicts + 1) >
m_params.m_arith_adaptive_propagation_threshold * get_context().m_stats.m_num_conflicts) {
m_num_propagation_calls = 1;
TRACE("arith_prop", tout << "propagating: " << m_num_propagation_calls << "\n";);
propagate_core();
}
else {
TRACE("arith_prop", tout << "skipping propagation " << m_num_propagation_calls << "\n";);
}
break;
}
case ARITH_PROP_AGILITY: {
// update agility with factor generated by other conflicts.
double g = m_params.m_arith_adaptive_propagation_threshold;
while (m_num_core_conflicts < get_context().m_stats.m_num_conflicts) {
m_agility = m_agility*g;
++m_num_core_conflicts;
}
++m_num_propagation_calls;
bool do_propagate = (m_num_propagation_calls * m_agility > m_params.m_arith_adaptive_propagation_threshold);
TRACE("arith_prop", tout << (do_propagate?"propagating: ":"skipping ")
<< " " << m_num_propagation_calls
<< " agility: " << m_agility << "\n";);
if (do_propagate) {
m_num_propagation_calls = 0;
propagate_core();
}
break;
}
default:
UNREACHABLE();
propagate_core();
}
}
else {
propagate_core();
}
}
template<typename Ext>
void theory_diff_logic<Ext>::inc_conflicts() {
m_stats.m_num_conflicts++;
if (m_params.m_arith_adaptive) {
double g = m_params.m_arith_adaptive_propagation_threshold;
m_agility = m_agility*g + 1 - g;
}
}
template<typename Ext>
void theory_diff_logic<Ext>::propagate_core() {
bool consistent = true;
while (consistent && can_propagate()) {
atom * a = m_asserted_atoms[m_asserted_qhead];
m_asserted_qhead++;
consistent = propagate_atom(a);
}
}
template<typename Ext>
bool theory_diff_logic<Ext>::propagate_atom(atom* a) {
context& ctx = get_context();
TRACE("arith", a->display(*this, tout); );
if (ctx.inconsistent()) {
return false;
}
switch(a->kind()) {
case LE_ATOM: {
int edge_id = dynamic_cast<le_atom*>(a)->get_asserted_edge();
if (!m_graph.enable_edge(edge_id)) {
set_neg_cycle_conflict();
return false;
}
#if 0
if (m_params.m_arith_bound_prop != BP_NONE) {
svector<int> subsumed;
m_graph.find_subsumed1(edge_id, subsumed);
for (unsigned i = 0; i < subsumed.size(); ++i) {
int subsumed_edge_id = subsumed[i];
literal l = m_graph.get_explanation(subsumed_edge_id);
context & ctx = get_context();
region& r = ctx.get_region();
++m_stats.m_num_th2core_prop;
ctx.assign(l, new (r) implied_bound_justification(*this, subsumed_edge_id, edge_id));
}
}
#endif
break;
}
case EQ_ATOM:
if (!a->is_true()) {
SASSERT(ctx.get_assignment(a->get_bool_var()) == l_false);
// eq_atom * ea = dynamic_cast<eq_atom*>(a);
}
break;
}
return true;
}
template<typename Ext>
void theory_diff_logic<Ext>::mark_as_modified_since_eq_prop() {
if (!m_modified_since_eq_prop) {
get_context().push_trail(value_trail<context, bool>(m_modified_since_eq_prop));
m_modified_since_eq_prop = true;
}
}
template<typename Ext>
void theory_diff_logic<Ext>::unmark_as_modified_since_eq_prop() {
get_context().push_trail(value_trail<context, bool>(m_modified_since_eq_prop));
m_modified_since_eq_prop = false;
}
template<typename Ext>
void theory_diff_logic<Ext>::del_clause_eh(clause* cls) {
}
template<typename Ext>
void theory_diff_logic<Ext>::new_edge(dl_var src, dl_var dst, unsigned num_edges, edge_id const* edges) {
if (!theory_resolve()) {
return;
}
TRACE("dl_activity", tout << "\n";);
context& ctx = get_context();
numeral w(0);
for (unsigned i = 0; i < num_edges; ++i) {
w += m_graph.get_weight(edges[i]);
}
enode* e1 = get_enode(src);
enode* e2 = get_enode(dst);
expr* n1 = e1->get_owner();
expr* n2 = e2->get_owner();
bool is_int = m_util.is_int(n1);
rational num = w.get_rational().to_rational();
expr_ref le(get_manager());
if (w.is_rational()) {
// x - y <= w
expr* n3 = m_util.mk_numeral(num, is_int);
n2 = m_util.mk_mul(m_util.mk_numeral(rational(-1), is_int), n2);
le = m_util.mk_le(m_util.mk_add(n1,n2), n3);
}
else {
// x - y < w
// <=>
// not (x - y >= w)
// <=>
// not (y - x <= -w)
//
SASSERT(w.get_infinitesimal().is_neg());
expr* n3 = m_util.mk_numeral(-num, is_int);
n1 = m_util.mk_mul(m_util.mk_numeral(rational(-1), is_int), n1);
le = m_util.mk_le(m_util.mk_add(n2,n1), n3);
le = get_manager().mk_not(le);
}
ctx.internalize(le, false);
ctx.mark_as_relevant(le.get());
literal lit(ctx.get_literal(le));
bool_var bv = lit.var();
atom* a = 0;
m_bool_var2atom.find(bv, a);
SASSERT(a);
edge_id e_id = static_cast<le_atom*>(a)->get_pos();
literal_vector lits;
for (unsigned i = 0; i < num_edges; ++i) {
lits.push_back(~m_graph.get_explanation(edges[i]));
}
lits.push_back(lit);
TRACE("dl_activity",
tout << mk_pp(le, get_manager()) << "\n";
tout << "edge: " << e_id << "\n";
ctx.display_literals_verbose(tout, lits.size(), lits.c_ptr());
tout << "\n";
);
justification * js = 0;
if (get_manager().proofs_enabled()) {
js = 0; // TBD?
}
clause_del_eh* del_eh = alloc(theory_diff_logic_del_eh, *this);
clause* cls = ctx.mk_clause(lits.size(), lits.c_ptr(), js, CLS_AUX_LEMMA, del_eh);
if (!cls) {
dealloc(del_eh);
}
if (dump_lemmas()) {
char const * logic = m_is_lia ? "QF_LIA" : "QF_LRA";
ctx.display_lemma_as_smt_problem(lits.size(), lits.c_ptr(), false_literal, logic);
}
#if 0
TRACE("arith",
tout << "shortcut:\n";
for (unsigned i = 0; i < num_edges; ++i) {
edge_id e = edges[i];
// tgt <= src + w
numeral w = m_graph.get_weight(e);
dl_var tgt = m_graph.get_target(e);
dl_var src = m_graph.get_source(e);
if (i + 1 < num_edges) {
dl_var tgt2 = m_graph.get_target(edges[i+1]);
SASSERT(src == tgt2);
}
tout << "$" << tgt << " <= $" << src << " + " << w << "\n";
}
{
numeral w = m_graph.get_weight(e_id);
dl_var tgt = m_graph.get_target(e_id);
dl_var src = m_graph.get_source(e_id);
tout << "$" << tgt << " <= $" << src << " + " << w << "\n";
}
);
#endif
}
template<typename Ext>
void theory_diff_logic<Ext>::set_neg_cycle_conflict() {
m_nc_functor.reset();
m_graph.traverse_neg_cycle2(m_params.m_arith_stronger_lemmas, m_nc_functor);
inc_conflicts();
literal_vector const& lits = m_nc_functor.get_lits();
context & ctx = get_context();
region& r = ctx.get_region();
TRACE("arith_conflict",
//display(tout);
tout << "conflict: ";
for (unsigned i = 0; i < lits.size(); ++i) {
ctx.display_literal_info(tout, lits[i]);
}
tout << "\n";
);
if (dump_lemmas()) {
char const * logic = m_is_lia ? "QF_LIA" : "QF_LRA";
ctx.display_lemma_as_smt_problem(lits.size(), lits.c_ptr(), false_literal, logic);
}
ctx.set_conflict(ctx.mk_justification(dl_conflict(r, lits.size(), lits.c_ptr())));
}
template<typename Ext>
bool theory_diff_logic<Ext>::is_offset(app* n, app*& v, app*& offset, rational& r) {
if (!m_util.is_add(n)) {
return false;
}
if (n->get_num_args() == 2 && m_util.is_numeral(n->get_arg(0), r)) {
v = to_app(n->get_arg(1));
offset = to_app(n->get_arg(0));
return true;
}
if (n->get_num_args() == 2 && m_util.is_numeral(n->get_arg(1), r)) {
v = to_app(n->get_arg(0));
offset = to_app(n->get_arg(1));
return true;
}
return false;
}
template<typename Ext>
theory_var theory_diff_logic<Ext>::mk_term(app* n) {
SASSERT(!m_util.is_sub(n));
SASSERT(!m_util.is_uminus(n));
app* a, *offset;
theory_var source, target;
enode* e;
TRACE("arith", tout << mk_pp(n, get_manager()) << "\n";);
rational r;
if (m_util.is_numeral(n, r)) {
return mk_num(n, r);
}
else if (is_offset(n, a, offset, r)) {
// n = a + k
source = mk_var(a);
e = get_context().mk_enode(n, false, false, true);
target = mk_var(e);
numeral k(r);
// target - source <= k, source - target <= -k
m_graph.enable_edge(m_graph.add_edge(source, target, k, null_literal));
m_graph.enable_edge(m_graph.add_edge(target, source, -k, null_literal));
return target;
}
else if (m_util.is_add(n)) {
return null_theory_var;
}
else if (m_util.is_mul(n)) {
return null_theory_var;
}
else if (m_util.is_div(n)) {
return null_theory_var;
}
else if (m_util.is_idiv(n)) {
return null_theory_var;
}
else if (m_util.is_mod(n)) {
return null_theory_var;
}
else if (m_util.is_rem(n)) {
return null_theory_var;
}
else {
return mk_var(n);
}
}
template<typename Ext>
theory_var theory_diff_logic<Ext>::mk_num(app* n, rational const& r) {
theory_var v = null_theory_var;
enode* e = 0;
context& ctx = get_context();
if (r.is_zero()) {
v = get_zero(n);
}
else if (ctx.e_internalized(n)) {
e = ctx.get_enode(n);
v = e->get_th_var(get_id());
SASSERT(v != null_theory_var);
}
else {
theory_var zero = get_zero(n);
e = ctx.mk_enode(n, false, false, true);
v = mk_var(e);
// internalizer is marking enodes as interpreted whenever the associated ast is a value and a constant.
// e->mark_as_interpreted();
numeral k(r);
// v = k: v - zero <= k, zero - v <= - k
m_graph.enable_edge(m_graph.add_edge(zero, v, k, null_literal));
m_graph.enable_edge(m_graph.add_edge(v, zero, -k, null_literal));
}
return v;
}
template<typename Ext>
theory_var theory_diff_logic<Ext>::mk_var(enode* n) {
mark_as_modified_since_eq_prop();
theory_var v = theory::mk_var(n);
TRACE("diff_logic_vars", tout << "mk_var: " << v << "\n";);
m_graph.init_var(v);
get_context().attach_th_var(n, this, v);
return v;
}
template<typename Ext>
bool theory_diff_logic<Ext>::is_interpreted(app* n) const {
return n->get_family_id() == get_family_id();
}
template<typename Ext>
theory_var theory_diff_logic<Ext>::mk_var(app* n) {
context & ctx = get_context();
enode* e = 0;
theory_var v = null_theory_var;
if (ctx.e_internalized(n)) {
e = ctx.get_enode(n);
v = e->get_th_var(get_id());
}
else {
ctx.internalize(n, false);
e = ctx.get_enode(n);
}
if (v == null_theory_var) {
v = mk_var(e);
}
if (is_interpreted(n)) {
found_non_diff_logic_expr(n);
}
TRACE("arith", tout << mk_pp(n, get_manager()) << " |-> " << v << "\n";);
return v;
}
template<typename Ext>
void theory_diff_logic<Ext>::reset_eh() {
for (unsigned i = 0; i < m_atoms.size(); ++i) {
dealloc(m_atoms[i]);
}
m_graph .reset();
m_zero_int = null_theory_var;
m_zero_real = null_theory_var;
m_atoms .reset();
m_asserted_atoms .reset();
m_stats .reset();
m_scopes .reset();
m_modified_since_eq_prop = false;
m_asserted_qhead = 0;
m_num_core_conflicts = 0;
m_num_propagation_calls = 0;
m_agility = 0.5;
m_is_lia = true;
m_non_diff_logic_exprs = false;
theory::reset_eh();
}
template<typename Ext>
bool theory_diff_logic<Ext>::propagate_cheap_equalities() {
bool result = false;
TRACE("dl_new_eq", get_context().display(tout););
context& ctx = get_context();
region& reg = ctx.get_region();
SASSERT(m_eq_prop_info_set.empty());
SASSERT(m_eq_prop_infos.empty());
if (m_modified_since_eq_prop) {
m_graph.compute_zero_edge_scc(m_scc_id);
int n = get_num_vars();
for (theory_var v = 0; v < n; v++) {
rational delta_r;
theory_var x_v = expand(true, v, delta_r);
numeral delta(delta_r);
int scc_id = m_scc_id[x_v];
if (scc_id != -1) {
delta += m_graph.get_assignment(x_v);
TRACE("eq_scc", tout << v << " " << x_v << " " << scc_id << " " << delta << "\n";);
eq_prop_info info(scc_id, delta);
typename eq_prop_info_set::entry * entry = m_eq_prop_info_set.find_core(&info);
if (entry == 0) {
eq_prop_info * new_info = alloc(eq_prop_info, scc_id, delta, v);
m_eq_prop_info_set.insert(new_info);
m_eq_prop_infos.push_back(new_info);
}
else {
// new equality found
theory_var r = entry->get_data()->get_root();
enode * n1 = get_enode(v);
enode * n2 = get_enode(r);
if (n1->get_root() != n2->get_root()) {
// r may be an alias (i.e., it is not realy in the graph). So, I should expand it.
// nsb: ??
rational r_delta;
theory_var x_r = expand(true, r, r_delta);
justification* j = new (reg) implied_eq_justification(*this, x_v, x_r, m_graph.get_timestamp());
(void)j;
m_stats.m_num_th2core_eqs++;
// TBD: get equality into core.
NOT_IMPLEMENTED_YET();
// new_eq_eh(x_v, x_r, *j);
result = true;
}
}
}
}
m_eq_prop_info_set.reset();
std::for_each(m_eq_prop_infos.begin(), m_eq_prop_infos.end(), delete_proc<eq_prop_info>());
m_eq_prop_infos.reset();
unmark_as_modified_since_eq_prop();
}
TRACE("dl_new_eq", get_context().display(tout););
SASSERT(!m_modified_since_eq_prop);
return result;
}
template<typename Ext>
void theory_diff_logic<Ext>::compute_delta() {
m_delta = rational(1);
unsigned num_edges = m_graph.get_num_edges();
for (unsigned i = 0; i < num_edges; ++i) {
if (!m_graph.is_enabled(i)) {
continue;
}
numeral w = m_graph.get_weight(i);
dl_var tgt = m_graph.get_target(i);
dl_var src = m_graph.get_source(i);
rational n_x = m_graph.get_assignment(tgt).get_rational().to_rational();
rational k_x = m_graph.get_assignment(tgt).get_infinitesimal().to_rational();
rational n_y = m_graph.get_assignment(src).get_rational().to_rational();
rational k_y = m_graph.get_assignment(src).get_infinitesimal().to_rational();
rational n_c = w.get_rational().to_rational();
rational k_c = w.get_infinitesimal().to_rational();
TRACE("epsilon", tout << "(n_x,k_x): " << n_x << ", " << k_x << ", (n_y,k_y): "
<< n_y << ", " << k_y << ", (n_c,k_c): " << n_c << ", " << k_c << "\n";);
if (n_x < n_y + n_c && k_x > k_y + k_c) {
rational new_delta = (n_y + n_c - n_x) / (k_x - k_y - k_c);
if (new_delta < m_delta) {
TRACE("epsilon", tout << "new delta: " << new_delta << "\n";);
m_delta = new_delta;
}
}
}
}
template<typename Ext>
void theory_diff_logic<Ext>::init_model(smt::model_generator & m) {
m_factory = alloc(arith_factory, get_manager());
m.register_factory(m_factory);
compute_delta();
}
template<typename Ext>
model_value_proc * theory_diff_logic<Ext>::mk_value(enode * n, model_generator & mg) {
theory_var v = n->get_th_var(get_id());
SASSERT(v != null_theory_var);
numeral val = m_graph.get_assignment(v);
rational num = val.get_rational().to_rational() + m_delta * val.get_infinitesimal().to_rational();
return alloc(expr_wrapper_proc, m_factory->mk_value(num, m_util.is_int(n->get_owner())));
}
template<typename Ext>
bool theory_diff_logic<Ext>::validate_eq_in_model(theory_var v1, theory_var v2, bool is_true) const {
NOT_IMPLEMENTED_YET();
return true;
}
template<typename Ext>
void theory_diff_logic<Ext>::display(std::ostream & out) const {
for (unsigned i = 0; i < m_atoms.size(); ++i) {
m_atoms[i]->display(*this, out);
}
m_graph.display(out);
}
template<typename Ext>
bool theory_diff_logic<Ext>::is_consistent() const {
context& ctx = get_context();
for (unsigned i = 0; i < m_atoms.size(); ++i) {
atom* a = m_atoms[i];
bool_var bv = a->get_bool_var();
lbool asgn = ctx.get_assignment(bv);
if (ctx.is_relevant(ctx.bool_var2expr(bv)) && asgn != l_undef) {
SASSERT((asgn == l_true) == a->is_true());
switch(a->kind()) {
case LE_ATOM: {
le_atom* le = dynamic_cast<le_atom*>(a);
int edge_id = le->get_asserted_edge();
SASSERT(m_graph.is_enabled(edge_id));
SASSERT(m_graph.is_feasible(edge_id));
break;
}
case EQ_ATOM: {
eq_atom* ea = dynamic_cast<eq_atom*>(a);
bool_var bv1 = ctx.get_bool_var(ea->get_le());
bool_var bv2 = ctx.get_bool_var(ea->get_ge());
lbool val1 = ctx.get_assignment(bv1);
lbool val2 = ctx.get_assignment(bv2);
if (asgn == l_true) {
SASSERT(val1 == l_true);
SASSERT(val2 == l_true);
}
else {
SASSERT(val1 == l_false || val2 == l_false);
}
break;
}
}
}
}
return m_graph.is_feasible();
}
template<class Ext>
theory_var theory_diff_logic<Ext>::expand(bool pos, theory_var v, rational & k) {
context& ctx = get_context();
enode* e = get_enode(v);
rational r;
for (;;) {
app* n = e->get_owner();
if (m_util.is_add(n) && n->get_num_args() == 2) {
app* x = to_app(n->get_arg(0));
app* y = to_app(n->get_arg(1));
if (m_util.is_numeral(x, r)) {
e = ctx.get_enode(y);
}
else if (m_util.is_numeral(y, r)) {
e = ctx.get_enode(x);
}
v = e->get_th_var(get_id());
SASSERT(v != null_theory_var);
if (v == null_theory_var) {
break;
}
if (pos) {
k += r;
}
else {
k -= r;
}
}
else {
break;
}
}
return v;
}
template<typename Ext>
void theory_diff_logic<Ext>::new_eq_or_diseq(bool is_eq, theory_var v1, theory_var v2, justification& eq_just) {
rational k;
theory_var s = expand(true, v1, k);
theory_var t = expand(false, v2, k);
context& ctx = get_context();
ast_manager& m = get_manager();
if (s == t) {
if (is_eq != k.is_zero()) {
// conflict 0 /= k;
inc_conflicts();
ctx.set_conflict(&eq_just);
}
}
else {
//
// Create equality ast, internalize_atom
// assign the corresponding equality literal.
//
mark_as_modified_since_eq_prop();
app_ref eq(m), s2(m), t2(m);
app* s1 = get_enode(s)->get_owner();
app* t1 = get_enode(t)->get_owner();
s2 = m_util.mk_sub(t1, s1);
t2 = m_util.mk_numeral(k, m.get_sort(s2.get()));
// t1 - s1 = k
eq = m.mk_eq(s2.get(), t2.get());
TRACE("diff_logic",
tout << v1 << " .. " << v2 << "\n";
tout << mk_pp(eq.get(), m) <<"\n";);
if (!internalize_atom(eq.get(), false)) {
UNREACHABLE();
}
literal l(ctx.get_literal(eq.get()));
if (!is_eq) {
l = ~l;
}
ctx.assign(l, b_justification(&eq_just), false);
}
}
template<typename Ext>
void theory_diff_logic<Ext>::new_eq_eh(
theory_var v1, theory_var v2, justification& j) {
m_stats.m_num_core2th_eqs++;
new_eq_or_diseq(true, v1, v2, j);
}
template<typename Ext>
void theory_diff_logic<Ext>::new_diseq_eh(
theory_var v1, theory_var v2, justification& j) {
m_stats.m_num_core2th_diseqs++;
new_eq_or_diseq(false, v1, v2, j);
}
template<typename Ext>
void theory_diff_logic<Ext>::new_eq_eh(theory_var v1, theory_var v2) {
m_arith_eq_adapter.new_eq_eh(v1, v2);
}
template<typename Ext>
void theory_diff_logic<Ext>::new_diseq_eh(theory_var v1, theory_var v2) {
m_arith_eq_adapter.new_diseq_eh(v1, v2);
}
template<typename Ext>
void theory_diff_logic<Ext>::relevant_eh(app* e) {
}
struct imp_functor {
conflict_resolution & m_cr;
imp_functor(conflict_resolution& cr) : m_cr(cr) {}
void operator()(literal l) {
m_cr.mark_literal(l);
}
};
template<typename Ext>
void theory_diff_logic<Ext>::get_eq_antecedents(
theory_var v1, theory_var v2, unsigned timestamp, conflict_resolution & cr) {
imp_functor functor(cr);
bool r;
r = m_graph.find_shortest_zero_edge_path(v1, v2, timestamp, functor);
SASSERT(r);
r = m_graph.find_shortest_zero_edge_path(v2, v1, timestamp, functor);
SASSERT(r);
}
template<typename Ext>
void theory_diff_logic<Ext>::get_implied_bound_antecedents(edge_id bridge_edge, edge_id subsumed_edge, conflict_resolution & cr) {
imp_functor f(cr);
m_graph.explain_subsumed_lazy(bridge_edge, subsumed_edge, f);
}
#endif /* _THEORY_DIFF_LOGIC_DEF_H_ */