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totalizer
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@NikolajBjorner
NikolajBjorner committed Jul 1, 2022
1 parent 959a0ba commit 94a2477
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Showing 6 changed files with 25 additions and 37 deletions.
19 changes: 7 additions & 12 deletions src/opt/maxcore.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -85,7 +85,6 @@ class maxcore : public maxsmt_solver_base {
s_primal_dual,
s_primal_binary,
s_rc2,
s_rc2tot,
s_primal_binary_rc2
};
private:
Expand Down Expand Up @@ -136,6 +135,7 @@ class maxcore : public maxsmt_solver_base {
bool m_enable_lns = false; // enable LNS improvements
unsigned m_lns_conflicts = 1000; // number of conflicts used for LNS improvement
bool m_enable_core_rotate = false; // enable core rotation
bool m_use_totalizer = true; // use totalizer instead of cardinality encoding
std::string m_trace_id;
typedef ptr_vector<expr> exprs;

Expand Down Expand Up @@ -165,9 +165,6 @@ class maxcore : public maxsmt_solver_base {
case s_rc2:
m_trace_id = "rc2";
break;
case s_rc2tot:
m_trace_id = "rc2tot";
break;
case s_primal_binary_rc2:
m_trace_id = "rc2bin";
break;
Expand All @@ -177,7 +174,10 @@ class maxcore : public maxsmt_solver_base {
}
}

~maxcore() override {}
~maxcore() override {
for (auto& [k,t] : m_totalizers)
dealloc(t);
}

bool is_literal(expr* l) {
return
Expand Down Expand Up @@ -374,7 +374,6 @@ class maxcore : public maxsmt_solver_base {
case s_primal:
case s_primal_binary:
case s_rc2:
case s_rc2tot:
case s_primal_binary_rc2:
return mus_solver();
case s_primal_dual:
Expand Down Expand Up @@ -567,7 +566,6 @@ class maxcore : public maxsmt_solver_base {
bin_max_resolve(core, w);
break;
case strategy_t::s_rc2:
case strategy_t::s_rc2tot:
max_resolve_rc2(core, w);
break;
case strategy_t::s_primal_binary_rc2:
Expand Down Expand Up @@ -820,7 +818,7 @@ class maxcore : public maxsmt_solver_base {
}

expr* mk_atmost(expr_ref_vector const& es, unsigned bound, rational const& weight) {
if (m_st == strategy_t::s_rc2tot)
if (m_use_totalizer)
return mk_atmost_tot(es, bound, weight);
pb_util pb(m);
expr_ref am(pb.mk_at_most_k(es, bound), m);
Expand Down Expand Up @@ -1064,6 +1062,7 @@ class maxcore : public maxsmt_solver_base {
m_enable_lns = p.enable_lns();
m_enable_core_rotate = p.enable_core_rotate();
m_lns_conflicts = p.lns_conflicts();
m_use_totalizer = p.rc2_totalizer();
if (m_c.num_objectives() > 1)
m_add_upper_bound_block = false;
}
Expand Down Expand Up @@ -1152,10 +1151,6 @@ opt::maxsmt_solver_base* opt::mk_rc2(
return alloc(maxcore, c, id, soft, maxcore::s_rc2);
}

opt::maxsmt_solver_base* opt::mk_rc2tot(
maxsat_context& c, unsigned id, vector<soft>& soft) {
return alloc(maxcore, c, id, soft, maxcore::s_rc2tot);
}

opt::maxsmt_solver_base* opt::mk_rc2bin(
maxsat_context& c, unsigned id, vector<soft>& soft) {
Expand Down
2 changes: 0 additions & 2 deletions src/opt/maxcore.h
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Original file line number Diff line number Diff line change
Expand Up @@ -23,8 +23,6 @@ namespace opt {

maxsmt_solver_base* mk_rc2(maxsat_context& c, unsigned id, vector<soft>& soft);

maxsmt_solver_base* mk_rc2tot(maxsat_context& c, unsigned id, vector<soft>& soft);

maxsmt_solver_base* mk_rc2bin(maxsat_context& c, unsigned id, vector<soft>& soft);

maxsmt_solver_base* mk_maxres(maxsat_context& c, unsigned id, vector<soft>& soft);
Expand Down
2 changes: 0 additions & 2 deletions src/opt/maxsmt.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -193,8 +193,6 @@ namespace opt {
m_msolver = mk_maxres_binary(m_c, m_index, m_soft);
else if (maxsat_engine == symbol("rc2"))
m_msolver = mk_rc2(m_c, m_index, m_soft);
else if (maxsat_engine == symbol("rc2tot"))
m_msolver = mk_rc2tot(m_c, m_index, m_soft);
else if (maxsat_engine == symbol("rc2bin"))
m_msolver = mk_rc2bin(m_c, m_index, m_soft);
else if (maxsat_engine == symbol("pd-maxres"))
Expand Down
1 change: 1 addition & 0 deletions src/opt/opt_params.pyg
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Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,7 @@ def_module_params('opt',
('pb.compile_equality', BOOL, False, 'compile arithmetical equalities into pseudo-Boolean equality (instead of two inequalites)'),
('pp.wcnf', BOOL, False, 'print maxsat benchmark into wcnf format'),
('maxlex.enable', BOOL, True, 'enable maxlex heuristic for lexicographic MaxSAT problems'),
('rc2.totalizer', BOOL, True, 'use totalizer for rc2 encoding'),
('maxres.hill_climb', BOOL, True, 'give preference for large weight cores'),
('maxres.add_upper_bound_block', BOOL, False, 'restict upper bound with constraint'),
('maxres.max_num_cores', UINT, 200, 'maximal number of cores per round'),
Expand Down
30 changes: 10 additions & 20 deletions src/opt/totalizer.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -37,7 +37,7 @@ namespace opt {
expr_ref c(m), def(m);
expr_ref_vector ors(m), clause(m);
for (unsigned i = k; i > 0 && !lits.get(i - 1); --i) {
if (l->m_literals.size() + r->m_literals.size() < i) {
if (l->size() + r->size() < i) {
lits[i - 1] = m.mk_false();
continue;
}
Expand All @@ -55,9 +55,9 @@ namespace opt {

for (unsigned j1 = 0; j1 <= i; ++j1) {
unsigned j2 = i - j1;
if (j1 > l->m_literals.size())
if (j1 > l->size())
continue;
if (j2 > r->m_literals.size())
if (j2 > r->size())
continue;
clause.reset();
if (0 < j1) {
Expand Down Expand Up @@ -93,37 +93,27 @@ namespace opt {
node* left = trees[i];
node* right = trees[i + 1];
expr_ref_vector ls(m);
ls.resize(left->m_literals.size() + right->m_literals.size());
ls.resize(left->size() + right->size());
node* n = alloc(node, ls);
n->m_left = left;
n->m_right = right;
trees.push_back(n);
}
m_tree = trees.back();
m_root = trees.back();
}

totalizer::~totalizer() {
ptr_vector<node> trees;
trees.push_back(m_tree);
while (!trees.empty()) {
node* n = trees.back();
trees.pop_back();
if (n->m_left)
trees.push_back(n->m_left);
if (n->m_right)
trees.push_back(n->m_right);
dealloc(n);
}
dealloc(m_root);
}

expr* totalizer::at_least(unsigned k) {
if (k == 0)
return m.mk_true();
if (m_tree->m_literals.size() < k)
if (m_root->size() < k)
return m.mk_false();
SASSERT(1 <= k && k <= m_tree->m_literals.size());
ensure_bound(m_tree, k);
return m_tree->m_literals.get(k - 1);
SASSERT(1 <= k && k <= m_root->size());
ensure_bound(m_root, k);
return m_root->m_literals.get(k - 1);
}

}
8 changes: 7 additions & 1 deletion src/opt/totalizer.h
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Original file line number Diff line number Diff line change
Expand Up @@ -26,11 +26,17 @@ namespace opt {
node* m_right = nullptr;
expr_ref_vector m_literals;
node(expr_ref_vector& l): m_literals(l) {}
~node() {
dealloc(m_left);
dealloc(m_right);
}
unsigned size() const { return m_literals.size(); }

};

ast_manager& m;
expr_ref_vector m_literals;
node* m_tree = nullptr;
node* m_root = nullptr;
expr_ref_vector m_clauses;
vector<std::pair<expr_ref, expr_ref>> m_defs;

Expand Down

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