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tune consequence finding. Factor solver pretty-printing as SMT-LIB into top-level

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2016-08-03 11:14:29 -07:00
parent cb2d8d2107
commit 491b3b34aa
15 changed files with 149 additions and 69 deletions
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91
src/smt/smt_consequences.cpp
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@ -102,7 +102,7 @@ namespace smt {
}
}
void context::delete_unfixed(obj_map<expr, expr*>& var2val) {
unsigned context::delete_unfixed(obj_map<expr, expr*>& var2val, expr_ref_vector& unfixed) {
ast_manager& m = m_manager;
ptr_vector<expr> to_delete;
obj_map<expr,expr*>::iterator it = var2val.begin(), end = var2val.end();
@ -137,14 +137,59 @@ namespace smt {
to_delete.push_back(k);
}
}
IF_VERBOSE(1, verbose_stream() << "(get-consequences deleting: " << to_delete.size() << " num-values: " << var2val.size() << ")\n";);
for (unsigned i = 0; i < to_delete.size(); ++i) {
var2val.remove(to_delete[i]);
unfixed.push_back(to_delete[i]);
}
return to_delete.size();
}
//
// Extract equalities that are congruent at the search level.
//
unsigned context::extract_fixed_eqs(obj_map<expr, expr*>& var2val, expr_ref_vector& conseq) {
ast_manager& m = m_manager;
ptr_vector<expr> to_delete;
expr_ref fml(m), eq(m);
obj_map<expr,expr*>::iterator it = var2val.begin(), end = var2val.end();
for (; it != end; ++it) {
expr* k = it->m_key;
expr* v = it->m_value;
if (!m.is_bool(k) && e_internalized(k) && e_internalized(v) &&
get_enode(k)->get_root() == get_enode(v)->get_root()) {
literal_vector literals;
m_conflict_resolution->eq2literals(get_enode(v), get_enode(k), literals);
uint_set s;
for (unsigned i = 0; i < literals.size(); ++i) {
SASSERT(get_assign_level(literals[i]) <= get_search_level());
s |= m_antecedents.find(literals[i].var());
}
fml = m.mk_eq(k, v);
fml = m.mk_implies(antecedent2fml(s), fml);
conseq.push_back(fml);
to_delete.push_back(k);
for (unsigned i = 0; i < literals.size(); ++i) {
literals[i].neg();
}
eq = mk_eq_atom(k, v);
internalize_formula(eq, false);
literal lit(get_bool_var(eq), true);
literals.push_back(lit);
mk_clause(literals.size(), literals.c_ptr(), 0);
}
}
for (unsigned i = 0; i < to_delete.size(); ++i) {
var2val.remove(to_delete[i]);
}
return to_delete.size();
}
lbool context::get_consequences(expr_ref_vector const& assumptions,
expr_ref_vector const& vars, expr_ref_vector& conseq) {
expr_ref_vector const& vars,
expr_ref_vector& conseq,
expr_ref_vector& unfixed) {
m_antecedents.reset();
lbool is_sat = check(assumptions.size(), assumptions.c_ptr());
@ -168,6 +213,9 @@ namespace smt {
trail.push_back(val);
var2val.insert(vars[i], val);
}
else {
unfixed.push_back(vars[i]);
}
}
extract_fixed_consequences(0, var2val, _assumptions, conseq);
unsigned num_units = assigned_literals().size();
@ -178,8 +226,10 @@ namespace smt {
m_case_split_queue->init_search_eh();
unsigned num_iterations = 0;
unsigned model_threshold = 2;
unsigned num_unfixed = 0;
unsigned num_fixed_eqs = 0;
unsigned num_reiterations = 0;
while (!var2val.empty()) {
++num_iterations;
obj_map<expr,expr*>::iterator it = var2val.begin();
expr* e = it->m_key;
expr* val = it->m_value;
@ -212,28 +262,50 @@ namespace smt {
}
if (get_assignment(lit) == l_true) {
var2val.erase(e);
unfixed.push_back(e);
}
else if (get_assign_level(lit) > get_search_level()) {
TRACE("context", tout << "Retry fixing: " << mk_pp(e, m) << "\n";);
pop_to_search_lvl();
++num_reiterations;
continue;
}
else {
TRACE("context", tout << "Fixed: " << mk_pp(e, m) << "\n";);
}
++num_iterations;
TRACE("context", tout << "Unfixed variables: " << var2val.size() << "\n";);
if (model_threshold <= num_iterations) {
delete_unfixed(var2val);
bool apply_slow_pass = model_threshold <= num_iterations || num_iterations <= 2;
if (apply_slow_pass) {
num_unfixed += delete_unfixed(var2val, unfixed);
// The next time we check the model is after 1.5 additional iterations.
model_threshold *= 3;
model_threshold /= 2;
model_threshold /= 2;
}
// repeat until we either have a model with negated literal or
// the literal is implied at base.
extract_fixed_consequences(num_units, var2val, _assumptions, conseq);
num_units = assigned_literals().size();
if (apply_slow_pass) {
num_fixed_eqs += extract_fixed_eqs(var2val, conseq);
IF_VERBOSE(1, verbose_stream() << "(get-consequences"
<< " iterations: " << num_iterations
<< " variables: " << var2val.size()
<< " fixed: " << conseq.size()
<< " unfixed: " << unfixed.size()
<< " fixed-eqs: " << num_fixed_eqs
<< " unfixed-deleted: " << num_unfixed
<< ")\n";);
TRACE("context", tout << "(get-consequences"
<< " iterations: " << num_iterations
<< " variables: " << var2val.size()
<< " fixed: " << conseq.size()
<< " unfixed: " << unfixed.size()
<< " fixed-eqs: " << num_fixed_eqs
<< " unfixed-deleted: " << num_unfixed
<< ")\n";);
}
if (var2val.contains(e)) {
TRACE("context", tout << "Fixed value to " << mk_pp(e, m) << " was not processed\n";);
expr_ref fml(m);
@ -242,8 +314,7 @@ namespace smt {
conseq.push_back(fml);
var2val.erase(e);
SASSERT(get_assignment(lit) == l_false);
}
}
}
end_search();
return l_true;