diff --git a/src/api/api_solver.cpp b/src/api/api_solver.cpp
index c6eae7488..09e522db2 100644
--- a/src/api/api_solver.cpp
+++ b/src/api/api_solver.cpp
@@ -479,12 +479,14 @@ extern "C" {
Z3_ast Z3_API Z3_solver_lookahead(Z3_context c,
Z3_solver s,
+ Z3_ast_vector assumptions,
Z3_ast_vector candidates) {
Z3_TRY;
- LOG_Z3_solver_lookahead(c, s, candidates);
+ LOG_Z3_solver_lookahead(c, s, assumptions, candidates);
ast_manager& m = mk_c(c)->m();
- expr_ref_vector _candidates(m);
+ expr_ref_vector _candidates(m), _assumptions(m);
ast_ref_vector const& __candidates = to_ast_vector_ref(candidates);
+ ast_ref_vector const& __assumptions = to_ast_vector_ref(assumptions);
for (auto & e : __candidates) {
if (!is_expr(e)) {
SET_ERROR_CODE(Z3_INVALID_USAGE);
@@ -492,6 +494,13 @@ extern "C" {
}
_candidates.push_back(to_expr(e));
}
+ for (auto & e : __assumptions) {
+ if (!is_expr(e)) {
+ SET_ERROR_CODE(Z3_INVALID_USAGE);
+ return 0;
+ }
+ _assumptions.push_back(to_expr(e));
+ }
expr_ref result(m);
unsigned timeout = to_solver(s)->m_params.get_uint("timeout", mk_c(c)->get_timeout());
@@ -504,7 +513,7 @@ extern "C" {
scoped_timer timer(timeout, &eh);
scoped_rlimit _rlimit(mk_c(c)->m().limit(), rlimit);
try {
- result = to_solver_ref(s)->lookahead(_candidates);
+ result = to_solver_ref(s)->lookahead(_assumptions, _candidates);
}
catch (z3_exception & ex) {
mk_c(c)->handle_exception(ex);
diff --git a/src/api/dotnet/Solver.cs b/src/api/dotnet/Solver.cs
index 6dd19cddf..078f5bc7a 100644
--- a/src/api/dotnet/Solver.cs
+++ b/src/api/dotnet/Solver.cs
@@ -255,11 +255,13 @@ namespace Microsoft.Z3
///
/// Select a lookahead literal from the set of supplied candidates.
///
- public BoolExpr Lookahead(IEnumerable candidates)
+ public BoolExpr Lookahead(IEnumerable assumptions, IEnumerable candidates)
{
ASTVector cands = new ASTVector(Context);
foreach (var c in candidates) cands.Push(c);
- return (BoolExpr)Expr.Create(Context, Native.Z3_solver_lookahead(Context.nCtx, NativeObject, cands.NativeObject));
+ ASTVector assums = new ASTVector(Context);
+ foreach (var c in assumptions) assums.Push(c);
+ return (BoolExpr)Expr.Create(Context, Native.Z3_solver_lookahead(Context.nCtx, NativeObject, assums.NativeObject, cands.NativeObject));
}
///
diff --git a/src/api/z3_api.h b/src/api/z3_api.h
index 4ae7c5c22..317b32923 100644
--- a/src/api/z3_api.h
+++ b/src/api/z3_api.h
@@ -6028,10 +6028,10 @@ extern "C" {
\brief select a literal from the list of candidate propositional variables to split on.
If the candidate list is empty, then the solver chooses a formula based on its internal state.
- def_API('Z3_solver_lookahead', AST, (_in(CONTEXT), _in(SOLVER), _in(AST_VECTOR)))
+ def_API('Z3_solver_lookahead', AST, (_in(CONTEXT), _in(SOLVER), _in(AST_VECTOR), _in(AST_VECTOR)))
*/
- Z3_ast Z3_API Z3_solver_lookahead(Z3_context c, Z3_solver s, Z3_ast_vector candidates);
+ Z3_ast Z3_API Z3_solver_lookahead(Z3_context c, Z3_solver s, Z3_ast_vector assumptions, Z3_ast_vector candidates);
/**
diff --git a/src/opt/opt_solver.h b/src/opt/opt_solver.h
index 24d0408fc..cef270abc 100644
--- a/src/opt/opt_solver.h
+++ b/src/opt/opt_solver.h
@@ -107,7 +107,7 @@ namespace opt {
virtual ast_manager& get_manager() const { return m; }
virtual lbool find_mutexes(expr_ref_vector const& vars, vector& mutexes);
virtual lbool preferred_sat(expr_ref_vector const& asms, vector& cores);
- virtual expr_ref lookahead(expr_ref_vector const& candidates) { return expr_ref(m.mk_true(), m); }
+ virtual expr_ref lookahead(expr_ref_vector const& assumptions, expr_ref_vector const& candidates) { return expr_ref(m.mk_true(), m); }
void set_logic(symbol const& logic);
smt::theory_var add_objective(app* term);
diff --git a/src/sat/sat_lookahead.cpp b/src/sat/sat_lookahead.cpp
index 97b4ef073..eeeff2c11 100644
--- a/src/sat/sat_lookahead.cpp
+++ b/src/sat/sat_lookahead.cpp
@@ -30,6 +30,18 @@ namespace sat {
if (p.m_s.m_ext) p.m_s.m_ext->set_lookahead(0);
}
+ lookahead::scoped_assumptions::scoped_assumptions(lookahead& p, literal_vector const& lits): p(p), lits(lits) {
+ for (auto l : lits) {
+ p.push(l, p.c_fixed_truth);
+ }
+ }
+ lookahead::scoped_assumptions::~scoped_assumptions() {
+ for (auto l : lits) {
+ p.pop();
+ }
+ }
+
+
void lookahead::flip_prefix() {
if (m_trail_lim.size() < 64) {
uint64 mask = (1ull << m_trail_lim.size());
@@ -1612,7 +1624,7 @@ namespace sat {
}
- literal lookahead::select_lookahead(bool_var_vector const& vars) {
+ literal lookahead::select_lookahead(literal_vector const& assumptions, bool_var_vector const& vars) {
IF_VERBOSE(1, verbose_stream() << "(sat-select " << vars.size() << ")\n";);
scoped_ext _sext(*this);
m_search_mode = lookahead_mode::searching;
@@ -1623,19 +1635,25 @@ namespace sat {
for (auto v : vars) {
m_select_lookahead_vars.insert(v);
}
+
+ scoped_assumptions _sa(*this, assumptions);
literal l = choose();
m_select_lookahead_vars.reset();
- if (inconsistent()) return null_literal;
+ if (inconsistent()) l = null_literal;
+#if 0
// assign unit literals that were found during search for lookahead.
- unsigned num_assigned = 0;
- for (literal lit : m_trail) {
- if (!m_s.was_eliminated(lit.var()) && m_s.value(lit) != l_true) {
- m_s.assign(lit, justification());
- ++num_assigned;
+ if (assumptions.empty()) {
+ unsigned num_assigned = 0;
+ for (literal lit : m_trail) {
+ if (!m_s.was_eliminated(lit.var()) && m_s.value(lit) != l_true) {
+ m_s.assign(lit, justification());
+ ++num_assigned;
+ }
}
+ IF_VERBOSE(1, verbose_stream() << "(sat-lookahead :units " << num_assigned << ")\n";);
}
- IF_VERBOSE(1, verbose_stream() << "(sat-lookahead :units " << num_assigned << ")\n";);
+#endif
return l;
}
diff --git a/src/sat/sat_lookahead.h b/src/sat/sat_lookahead.h
index 028e94786..2b8ddc594 100644
--- a/src/sat/sat_lookahead.h
+++ b/src/sat/sat_lookahead.h
@@ -199,6 +199,14 @@ namespace sat {
~scoped_ext();
};
+ class scoped_assumptions {
+ lookahead& p;
+ literal_vector lits;
+ public:
+ scoped_assumptions(lookahead& p, literal_vector const& lits);
+ ~scoped_assumptions();
+ };
+
// -------------------------------------
// prefix updates. I use low order bits.
@@ -447,7 +455,7 @@ namespace sat {
return search();
}
- literal select_lookahead(bool_var_vector const& vars);
+ literal select_lookahead(literal_vector const& assumptions, bool_var_vector const& vars);
/**
\brief simplify set of clauses by extracting units from a lookahead at base level.
*/
diff --git a/src/sat/sat_solver.cpp b/src/sat/sat_solver.cpp
index 1f8f3aa19..77a816660 100644
--- a/src/sat/sat_solver.cpp
+++ b/src/sat/sat_solver.cpp
@@ -811,14 +811,9 @@ namespace sat {
return r;
}
- literal solver::select_lookahead(bool_var_vector const& vars) {
+ literal solver::select_lookahead(literal_vector const& assumptions, bool_var_vector const& vars) {
lookahead lh(*this);
- literal result = lh.select_lookahead(vars);
- if (result == null_literal) {
- set_conflict(justification());
- }
- // extract unit literals from lh
- return result;
+ return lh.select_lookahead(assumptions, vars);
}
// -----------------------
@@ -851,8 +846,8 @@ namespace sat {
}
#endif
try {
- if (inconsistent()) return l_false;
init_search();
+ if (inconsistent()) return l_false;
propagate(false);
if (inconsistent()) return l_false;
init_assumptions(num_lits, lits);
diff --git a/src/sat/sat_solver.h b/src/sat/sat_solver.h
index 348e1cd22..b6dffe511 100644
--- a/src/sat/sat_solver.h
+++ b/src/sat/sat_solver.h
@@ -355,7 +355,7 @@ namespace sat {
void set_model(model const& mdl);
char const* get_reason_unknown() const { return m_reason_unknown.c_str(); }
- literal select_lookahead(bool_var_vector const& vars);
+ literal select_lookahead(literal_vector const& assumptions, bool_var_vector const& vars);
protected:
unsigned m_conflicts;
diff --git a/src/sat/sat_solver/inc_sat_solver.cpp b/src/sat/sat_solver/inc_sat_solver.cpp
index 3fa9f4c81..9d9c24b8f 100644
--- a/src/sat/sat_solver/inc_sat_solver.cpp
+++ b/src/sat/sat_solver/inc_sat_solver.cpp
@@ -148,6 +148,8 @@ public:
virtual lbool check_sat(unsigned sz, expr * const * assumptions) {
m_solver.pop_to_base_level();
+ m_core.reset();
+ if (m_solver.inconsistent()) return l_false;
expr_ref_vector _assumptions(m);
obj_map asm2fml;
for (unsigned i = 0; i < sz; ++i) {
@@ -280,9 +282,10 @@ public:
return 0;
}
- virtual expr_ref lookahead(expr_ref_vector const& candidates) {
+ virtual expr_ref lookahead(expr_ref_vector const& assumptions, expr_ref_vector const& candidates) {
IF_VERBOSE(1, verbose_stream() << "(sat-lookahead " << candidates.size() << ")\n";);
sat::bool_var_vector vars;
+ sat::literal_vector lits;
expr_ref_vector lit2expr(m);
lit2expr.resize(m_solver.num_vars() * 2);
m_map.mk_inv(lit2expr);
@@ -292,11 +295,29 @@ public:
vars.push_back(v);
}
}
+ for (auto c : assumptions) {
+ SASSERT(is_literal(c));
+ sat::bool_var v = sat::null_bool_var;
+ bool sign = false;
+ expr* e = c;
+ while (m.is_not(e, e)) {
+ sign = !sign;
+ }
+ if (is_uninterp_const(e)) {
+ v = m_map.to_bool_var(e);
+ }
+ if (v != sat::null_bool_var) {
+ lits.push_back(sat::literal(v, sign));
+ }
+ else {
+ IF_VERBOSE(0, verbose_stream() << "WARNING: could not handle " << mk_pp(c, m) << "\n";);
+ }
+ }
IF_VERBOSE(1, verbose_stream() << "vars: " << vars.size() << "\n";);
if (vars.empty()) {
return expr_ref(m.mk_true(), m);
}
- sat::literal l = m_solver.select_lookahead(vars);
+ sat::literal l = m_solver.select_lookahead(lits, vars);
if (m_solver.inconsistent()) {
IF_VERBOSE(1, verbose_stream() << "(sat-lookahead inconsistent)\n";);
return expr_ref(m.mk_false(), m);
@@ -715,7 +736,7 @@ private:
if (asm2fml.contains(e)) {
e = asm2fml.find(e);
}
- m_core.push_back(e);
+ m_core.push_back(e);
}
}
diff --git a/src/smt/smt_solver.cpp b/src/smt/smt_solver.cpp
index 2ca5a11c3..ef81fbfd2 100644
--- a/src/smt/smt_solver.cpp
+++ b/src/smt/smt_solver.cpp
@@ -219,7 +219,7 @@ namespace smt {
return m_context.get_formulas()[idx];
}
- virtual expr_ref lookahead(expr_ref_vector const& candidates) {
+ virtual expr_ref lookahead(expr_ref_vector const& assumptions, expr_ref_vector const& candidates) {
ast_manager& m = get_manager();
return expr_ref(m.mk_true(), m);
}
diff --git a/src/solver/combined_solver.cpp b/src/solver/combined_solver.cpp
index 5d6cd232f..b23aabc2d 100644
--- a/src/solver/combined_solver.cpp
+++ b/src/solver/combined_solver.cpp
@@ -274,8 +274,8 @@ public:
return m_solver1->get_num_assumptions() + m_solver2->get_num_assumptions();
}
- virtual expr_ref lookahead(expr_ref_vector const& candidates) {
- return m_solver1->lookahead(candidates);
+ virtual expr_ref lookahead(expr_ref_vector const& assumptions, expr_ref_vector const& candidates) {
+ return m_solver1->lookahead(assumptions, candidates);
}
virtual expr * get_assumption(unsigned idx) const {
diff --git a/src/solver/solver.h b/src/solver/solver.h
index 56890f7c0..5346cf4a4 100644
--- a/src/solver/solver.h
+++ b/src/solver/solver.h
@@ -176,7 +176,7 @@ public:
\brief extract a lookahead candidates for branching.
*/
- virtual expr_ref lookahead(expr_ref_vector const& candidates) = 0;
+ virtual expr_ref lookahead(expr_ref_vector const& assumptions, expr_ref_vector const& candidates) = 0;
/**
\brief extract learned lemmas.
diff --git a/src/solver/tactic2solver.cpp b/src/solver/tactic2solver.cpp
index f9d5a4b0f..d3d8e59ce 100644
--- a/src/solver/tactic2solver.cpp
+++ b/src/solver/tactic2solver.cpp
@@ -76,7 +76,7 @@ public:
virtual ast_manager& get_manager() const;
- virtual expr_ref lookahead(expr_ref_vector const& candidates) {
+ virtual expr_ref lookahead(expr_ref_vector const& assumptions, expr_ref_vector const& candidates) {
ast_manager& m = get_manager();
std::cout << "tactic2solver\n";
return expr_ref(m.mk_true(), m);
diff --git a/src/tactic/portfolio/bounded_int2bv_solver.cpp b/src/tactic/portfolio/bounded_int2bv_solver.cpp
index aeaa88bc2..746856543 100644
--- a/src/tactic/portfolio/bounded_int2bv_solver.cpp
+++ b/src/tactic/portfolio/bounded_int2bv_solver.cpp
@@ -149,7 +149,7 @@ public:
virtual void set_reason_unknown(char const* msg) { m_solver->set_reason_unknown(msg); }
virtual void get_labels(svector & r) { m_solver->get_labels(r); }
virtual ast_manager& get_manager() const { return m; }
- virtual expr_ref lookahead(expr_ref_vector const& candidates) { flush_assertions(); return m_solver->lookahead(candidates); }
+ virtual expr_ref lookahead(expr_ref_vector const& assumptions, expr_ref_vector const& candidates) { flush_assertions(); return m_solver->lookahead(assumptions, candidates); }
virtual void get_lemmas(expr_ref_vector & lemmas) { flush_assertions(); m_solver->get_lemmas(lemmas); }
virtual lbool find_mutexes(expr_ref_vector const& vars, vector& mutexes) { return m_solver->find_mutexes(vars, mutexes); }
virtual lbool get_consequences_core(expr_ref_vector const& asms, expr_ref_vector const& vars, expr_ref_vector& consequences) {
diff --git a/src/tactic/portfolio/enum2bv_solver.cpp b/src/tactic/portfolio/enum2bv_solver.cpp
index d50dee57c..67be432c2 100644
--- a/src/tactic/portfolio/enum2bv_solver.cpp
+++ b/src/tactic/portfolio/enum2bv_solver.cpp
@@ -97,7 +97,7 @@ public:
virtual void get_labels(svector & r) { m_solver->get_labels(r); }
virtual ast_manager& get_manager() const { return m; }
virtual lbool find_mutexes(expr_ref_vector const& vars, vector& mutexes) { return m_solver->find_mutexes(vars, mutexes); }
- virtual expr_ref lookahead(expr_ref_vector const& candidates) { return m_solver->lookahead(candidates); }
+ virtual expr_ref lookahead(expr_ref_vector const& assumptions, expr_ref_vector const& candidates) { return m_solver->lookahead(assumptions, candidates); }
virtual void get_lemmas(expr_ref_vector & lemmas) { m_solver->get_lemmas(lemmas); }
virtual lbool get_consequences_core(expr_ref_vector const& asms, expr_ref_vector const& vars, expr_ref_vector& consequences) {
diff --git a/src/tactic/portfolio/pb2bv_solver.cpp b/src/tactic/portfolio/pb2bv_solver.cpp
index 46a5912b0..27e2a5850 100644
--- a/src/tactic/portfolio/pb2bv_solver.cpp
+++ b/src/tactic/portfolio/pb2bv_solver.cpp
@@ -93,7 +93,7 @@ public:
virtual void set_reason_unknown(char const* msg) { m_solver->set_reason_unknown(msg); }
virtual void get_labels(svector & r) { m_solver->get_labels(r); }
virtual ast_manager& get_manager() const { return m; }
- virtual expr_ref lookahead(expr_ref_vector const& candidates) { flush_assertions(); return m_solver->lookahead(candidates); }
+ virtual expr_ref lookahead(expr_ref_vector const& assumptions, expr_ref_vector const& candidates) { flush_assertions(); return m_solver->lookahead(assumptions, candidates); }
virtual void get_lemmas(expr_ref_vector & lemmas) { flush_assertions(); m_solver->get_lemmas(lemmas); }
virtual lbool find_mutexes(expr_ref_vector const& vars, vector& mutexes) { return m_solver->find_mutexes(vars, mutexes); }
virtual lbool get_consequences_core(expr_ref_vector const& asms, expr_ref_vector const& vars, expr_ref_vector& consequences) {