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removing unused and fixing suspect optimization

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2019-02-16 21:26:29 -08:00
parent ea778eefb2
commit 8c085f1a18
1 changed files with 8 additions and 129 deletions
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137
src/opt/maxlex.cpp
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@ -74,11 +74,6 @@ namespace opt {
}
}
void set_value(soft& soft, lbool v) {
soft.set_value(v);
assert_value(soft);
}
void update_assignment(model_ref & mdl) {
bool first_undef = true, second_undef = false;
for (auto & soft : m_soft) {
@ -95,7 +90,9 @@ namespace opt {
soft.set_value(v);
}
else {
set_value(soft, v); // also update constraints
SASSERT(v == l_true);
soft.set_value(v);
assert_value(soft);
}
}
}
@ -130,121 +127,8 @@ namespace opt {
if (mdl) update_assignment(mdl);
}
lbool maxlex1() {
for (auto & soft : m_soft) {
if (soft.value == l_true) {
continue;
}
SASSERT(soft.value == l_undef);
expr* a = soft.s;
lbool is_sat = s().check_sat(1, &a);
switch (is_sat) {
case l_false:
set_value(soft, l_false);
update_bounds();
break;
case l_true:
update_assignment();
SASSERT(soft.value == l_true);
break;
case l_undef:
return l_undef;
}
}
return l_true;
}
// try two literals per round.
// doesn't seem to make a difference based on sample test.
lbool maxlex2() {
unsigned sz = m_soft.size();
for (unsigned i = 0; i < sz; ++i) {
auto& soft = m_soft[i];
if (soft.value != l_undef) {
continue;
}
SASSERT(soft.value == l_undef);
if (i + 1 == sz) {
expr* a = soft.s;
lbool is_sat = s().check_sat(1, &a);
switch (is_sat) {
case l_false:
set_value(soft, l_false);
update_bounds();
break;
case l_true:
update_assignment();
SASSERT(soft.value == l_true);
break;
case l_undef:
return l_undef;
}
}
else {
auto& soft2 = m_soft[i+1];
expr_ref_vector core(m);
expr* a = soft.s;
expr* b = soft2.s;
expr* asms[2] = { a, b };
lbool is_sat = s().check_sat(2, asms);
switch (is_sat) {
case l_true:
update_assignment();
SASSERT(soft.value == l_true);
SASSERT(soft2.value == l_true);
break;
case l_false:
s().get_unsat_core(core);
if (core.contains(b)) {
expr_ref not_b(mk_not(m, b), m);
asms[1] = not_b;
switch (s().check_sat(2, asms)) {
case l_true:
// a, b is unsat, a, not b is sat.
set_value(soft2, l_false);
update_assignment();
SASSERT(soft.value == l_true);
SASSERT(soft2.value == l_false);
break;
case l_false:
// a, b is unsat, a, not b is unsat -> a is unsat
// b is unsat, a, not b is unsat -> not a, not b
set_value(soft, l_false);
// core1 = { b }
// core2 = { a, not b }
if (!core.contains(a)) {
set_value(soft2, l_false);
}
else {
// core1 = { a, b}
// core2 = { not_b }
core.reset();
s().get_unsat_core(core);
if (!core.contains(a)) {
set_value(soft2, l_true);
}
}
update_bounds();
break;
case l_undef:
return l_undef;
}
}
else {
set_value(soft, l_false);
update_bounds();
}
break;
case l_undef:
return l_undef;
}
}
}
return l_true;
}
// every time probing whether to include soft_i,
// include suffix that is known to be assignable to T
//
// include soft constraints that are known to be assignable to true after failed literal.
//
lbool maxlexN() {
unsigned sz = m_soft.size();
@ -255,12 +139,6 @@ namespace opt {
}
expr_ref_vector asms(m);
asms.push_back(soft.s);
for (unsigned j = i + 1; j < sz; ++j) {
auto& soft2 = m_soft[j];
if (soft2.value == l_true) {
asms.push_back(soft2.s);
}
}
lbool is_sat = s().check_sat(asms);
switch (is_sat) {
case l_true:
@ -268,7 +146,8 @@ namespace opt {
SASSERT(soft.value == l_true);
break;
case l_false:
set_value(soft, l_false);
soft.set_value(l_false);
assert_value(soft);
for (unsigned j = i + 1; j < sz; ++j) {
auto& soft2 = m_soft[j];
if (soft2.value != l_true) {
@ -298,7 +177,7 @@ namespace opt {
lbool operator()() override {
init();
return maxlex1();
return maxlexN();
}