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aig-simplifier: add root tracking, make incremental, split files

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2020-01-09 08:56:21 -08:00
parent 192c6e39c2
commit a18d2a606b
7 changed files with 146 additions and 20 deletions
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112
src/sat/sat_aig_cuts.cpp
View file

@ -24,10 +24,13 @@ namespace sat {
m_config.m_max_cut_size = std::min(cut().max_cut_size, m_config.m_max_cut_size);
m_cut_set1.init(m_region, m_config.m_max_cutset_size + 1);
m_cut_set2.init(m_region, m_config.m_max_cutset_size + 1);
m_true = null_bool_var;
}
vector<cut_set> const& aig_cuts::get_cuts() {
flush_roots();
unsigned_vector node_ids = filter_valid_nodes();
TRACE("aig_simplifier", display(tout););
augment(node_ids);
TRACE("aig_simplifier", display(tout););
return m_cuts;
@ -38,15 +41,17 @@ namespace sat {
cut_set& cs = m_cuts[id];
node const& n = m_aig[id];
SASSERT(n.is_valid());
// cs.display(std::cout << "augment " << id << "\nbefore\n");
augment(n, cs);
for (node const& n2 : m_aux_aig[id]) {
augment(n2, cs);
}
// cs.display(std::cout << "after\n");
}
}
void aig_cuts::augment(node const& n, cut_set& cs) {
unsigned nc = n.num_children();
unsigned nc = n.is_var() ? 0 : n.num_children();
if (n.is_var()) {
SASSERT(!n.sign());
}
@ -68,6 +73,7 @@ namespace sat {
}
bool aig_cuts::insert_cut(cut const& c, cut_set& cs) {
SASSERT(c.m_size > 0);
while (cs.size() >= m_config.m_max_cutset_size) {
// never evict the first entry, it is used for the starting point
unsigned idx = 1 + (m_rand() % (cs.size() - 1));
@ -110,15 +116,16 @@ namespace sat {
void aig_cuts::augment_aig0(node const& n, cut_set& cs) {
SASSERT(n.is_and());
cut c;
SASSERT(m_true != null_bool_var);
cut c(m_true);
cs.reset();
if (n.sign()) {
c.m_table = 0; // constant false
c.m_table = 0x0; // constant false
}
else {
c.m_table = 0x3; // constant true
}
cs.insert(c);
cs.push_back(c);
}
void aig_cuts::augment_aig1(node const& n, cut_set& cs) {
@ -126,7 +133,7 @@ namespace sat {
literal lit = child(n, 0);
unsigned round = 0;
for (auto const& a : m_cuts[lit.var()]) {
cut c;
cut c(lit.var());
c.set_table(a.m_table);
if (n.sign()) c.negate();
if (insert_cut(c, cs) && ++round >= m_config.m_max_insertions)
@ -219,28 +226,106 @@ namespace sat {
unsigned offset = m_literals.size();
node n(head.sign(), op, sz, offset);
m_literals.append(sz, args);
if (op == and_op || op == xor_op) {
std::sort(m_literals.c_ptr() + offset, m_literals.c_ptr() + offset + sz);
}
for (unsigned i = 0; i < sz; ++i) {
if (!m_aig[args[i].var()].is_valid()) {
add_var(args[i].var());
}
}
if (!m_aig[v].is_valid() || m_aig[v].is_var() || (sz == 0)) {
if (n.is_const() && m_true == null_bool_var) {
m_true = v;
}
if (!m_aig[v].is_valid() || m_aig[v].is_var() || n.is_const()) {
m_aig[v] = n;
init_cut_set(v);
if (n.is_const()) {
augment_aig0(n, m_cuts[v]);
}
}
else if (eq(n, m_aig[v]) || !insert_aux(v, n)) {
else if (m_aig[v].is_const() || eq(n, m_aig[v]) || !insert_aux(v, n)) {
m_literals.shrink(m_literals.size() - sz);
TRACE("aig_simplifier", tout << "duplicate\n";);
}
for (auto const& c : m_cuts[v]) SASSERT(c.m_size > 0);
SASSERT(m_aig[v].is_valid());
}
void aig_cuts::set_root(bool_var v, literal r) {
IF_VERBOSE(2, verbose_stream() << "set-root " << v << " -> " << r << "\n");
m_roots.push_back(std::make_pair(v, r));
}
void aig_cuts::flush_roots() {
if (m_roots.empty()) return;
literal_vector to_root;
for (unsigned i = 0; i < m_aig.size(); ++i) {
to_root.push_back(literal(i, false));
}
for (unsigned i = m_roots.size(); i-- > 0; ) {
bool_var v = m_roots[i].first;
literal r = m_roots[i].second;
literal rr = to_root[r.var()];
to_root[v] = r.sign() ? ~rr : rr;
}
for (unsigned i = 0; i < m_aig.size(); ++i) {
node& n = m_aig[i];
// invalidate nodes that have been rooted
if (to_root[i] != literal(i, false)) {
m_aux_aig[i].reset();
m_aig[i] = node();
m_cuts[i].reset();
}
else if (n.is_valid()) {
flush_roots(to_root, n);
for (node & n2 : m_aux_aig[i]) {
flush_roots(to_root, n2);
}
}
}
for (cut_set& cs : m_cuts) {
flush_roots(to_root, cs);
}
m_roots.reset();
TRACE("aig_simplifier", display(tout););
}
void aig_cuts::flush_roots(literal_vector const& to_root, node& n) {
bool changed = false;
for (unsigned i = 0; i < n.num_children(); ++i) {
literal& lit = m_literals[n.offset() + i];
if (to_root[lit.var()] != lit) {
changed = true;
lit = lit.sign() ? ~to_root[lit.var()] : to_root[lit.var()];
}
}
if (changed) {
std::sort(m_literals.c_ptr() + n.offset(), m_literals.c_ptr() + n.offset() + n.num_children());
}
}
void aig_cuts::flush_roots(literal_vector const& to_root, cut_set& cs) {
unsigned j = 0;
for (cut& c : cs) {
bool has_stale = false;
for (unsigned v : c) {
has_stale |= (to_root[v] != literal(v, false));
}
if (!has_stale) {
cs[j++] = c;
}
}
cs.shrink(j);
}
void aig_cuts::init_cut_set(unsigned id) {
node const& n = m_aig[id];
SASSERT(n.is_valid());
auto& cut_set = m_cuts[id];
cut_set.init(m_region, m_config.m_max_cutset_size + 1);
cut_set.push_back(cut(id)); // TBD: if entry is a constant?
cut_set.reset();
cut_set.push_back(cut(id));
m_aux_aig[id].reset();
}
@ -281,8 +366,9 @@ namespace sat {
out << id << " == ";
display(out, m_aig[id]) << "\n";
for (auto const& n : m_aux_aig[id]) {
display(out << " ", n) << "\n";
display(out << " ", n) << "\n";
}
m_cuts[id].display(out);
}
return out;
}
@ -290,10 +376,10 @@ namespace sat {
std::ostream& aig_cuts::display(std::ostream& out, node const& n) const {
if (n.sign()) out << "! ";
switch (n.op()) {
case var_op: out << "var "; break;
case and_op: out << "and "; break;
case xor_op: out << "xor "; break;
case ite_op: out << "ite "; break;
case var_op: out << "var "; return out;
case and_op: out << "& "; break;
case xor_op: out << "^ "; break;
case ite_op: out << "? "; break;
default: break;
}
for (unsigned i = 0; i < n.num_children(); ++i) {

22
src/sat/sat_aig_cuts.h
View file

@ -31,6 +31,16 @@ namespace sat {
no_op
};
inline std::ostream& operator<<(std::ostream& out, bool_op op) {
switch (op) {
case var_op: return out << "v";
case and_op: return out << "&";
case ite_op: return out << "?";
case xor_op: return out << "^";
default: return out << "";
}
}
class aig_cuts {
struct config {
@ -50,14 +60,15 @@ namespace sat {
public:
node(): m_sign(false), m_op(no_op), m_num_children(UINT_MAX), m_offset(UINT_MAX) {}
explicit node(unsigned v): m_sign(false), m_op(var_op), m_num_children(UINT_MAX), m_offset(v) {}
explicit node(bool negate, bool_op op, unsigned num_children, unsigned offset):
m_sign(negate), m_op(op), m_num_children(num_children), m_offset(offset) {}
explicit node(bool negate, bool_op op, unsigned nc, unsigned o):
m_sign(negate), m_op(op), m_num_children(nc), m_offset(o) {}
bool is_valid() const { return m_offset != UINT_MAX; }
bool_op op() const { return m_op; }
bool is_var() const { return m_op == var_op; }
bool is_and() const { return m_op == and_op; }
bool is_xor() const { return m_op == xor_op; }
bool is_ite() const { return m_op == ite_op; }
bool is_const() const { return is_and() && num_children() == 0; }
unsigned var() const { SASSERT(is_var()); return m_offset; }
bool sign() const { return m_sign; }
unsigned num_children() const { SASSERT(!is_var()); return m_num_children; }
@ -71,6 +82,8 @@ namespace sat {
region m_region;
cut_set m_cut_set1, m_cut_set2;
vector<cut_set> m_cuts;
bool_var m_true;
svector<std::pair<bool_var, literal>> m_roots;
void reserve(unsigned v);
bool insert_aux(unsigned v, node const& n);
@ -89,6 +102,10 @@ namespace sat {
bool insert_cut(cut const& c, cut_set& cs);
void flush_roots();
void flush_roots(literal_vector const& to_root, node& n);
void flush_roots(literal_vector const& to_root, cut_set& cs);
std::ostream& display(std::ostream& out, node const& n) const;
literal child(node const& n, unsigned idx) const { SASSERT(!n.is_var()); SASSERT(idx < n.num_children()); return m_literals[n.offset() + idx]; }
@ -97,6 +114,7 @@ namespace sat {
aig_cuts();
void add_var(unsigned v);
void add_node(literal head, bool_op op, unsigned sz, literal const* args);
void set_root(bool_var v, literal r);
vector<cut_set> const & get_cuts();

5
src/sat/sat_aig_simplifier.cpp
View file

@ -76,6 +76,10 @@ namespace sat {
m_stats.m_num_xors++;
}
void aig_simplifier::set_root(bool_var v, literal r) {
m_aig_cuts.set_root(v, r);
}
void aig_simplifier::operator()() {
report _report(*this);
TRACE("aig_simplifier", s.display(tout););
@ -159,6 +163,7 @@ namespace sat {
for (auto& cut : cuts[i]) {
unsigned j = 0;
if (cut2id.find(&cut, j)) {
if (i == j) std::cout << "dup: " << i << "\n";
VERIFY(i != j);
literal v(i, false);
literal w(j, false);

1
src/sat/sat_aig_simplifier.h
View file

@ -51,6 +51,7 @@ namespace sat {
void add_xor(literal head, unsigned sz, literal const* args);
void add_ite(literal head, literal c, literal t, literal e);
void add_iff(literal head, literal l1, literal l2);
void set_root(bool_var v, literal r);
};
}

17
src/sat/sat_cutset.cpp
View file

@ -33,6 +33,7 @@ namespace sat {
*/
bool cut_set::insert(cut const& c) {
SASSERT(c.m_size > 0);
unsigned i = 0, j = 0;
for (; i < size(); ++i) {
cut const& a = (*this)[i];
@ -61,6 +62,14 @@ namespace sat {
}
return true;
}
std::ostream& cut_set::display(std::ostream& out) const {
for (auto const& cut : *this) {
cut.display(out) << "\n";
}
return out;
}
/**
\brief shift table 'a' by adding elements from 'c'.
@ -116,10 +125,12 @@ namespace sat {
}
std::ostream& cut::display(std::ostream& out) const {
out << "{";
for (unsigned i = 0; i < m_size; ++i) {
out << (*this)[i] << " ";
}
out << "t: ";
out << (*this)[i];
if (i + 1 < m_size) out << " ";
}
out << "} t: ";
for (unsigned i = 0; i < (1u << m_size); ++i) {
if (0 != (m_table & (1ull << i))) out << "1"; else out << "0";
}

8
src/sat/sat_cutset.h
View file

@ -111,9 +111,11 @@ namespace sat {
public:
cut_set(): m_region(nullptr), m_size(0), m_max_size(0), m_cuts(nullptr) {}
void init(region& r, unsigned sz) {
m_max_size = sz;
SASSERT(!m_region || m_cuts);
if (m_region) return;
m_region = &r;
m_cuts = new (r) cut[sz];
m_max_size = sz;
}
bool insert(cut const& c);
bool no_duplicates() const;
@ -121,7 +123,8 @@ namespace sat {
cut * begin() const { return m_cuts; }
cut * end() const { return m_cuts + m_size; }
cut & back() { return m_cuts[m_size-1]; }
void push_back(cut const& c) {
void push_back(cut const& c) {
SASSERT(c.m_size > 0);
if (m_size == m_max_size) {
m_max_size *= 2;
cut* new_cuts = new (*m_region) cut[m_max_size];
@ -135,6 +138,7 @@ namespace sat {
void shrink(unsigned j) { m_size = j; }
void swap(cut_set& other) { std::swap(m_size, other.m_size); std::swap(m_cuts, other.m_cuts); std::swap(m_max_size, other.m_max_size); }
void evict(unsigned idx) { m_cuts[idx] = m_cuts[--m_size]; }
std::ostream& display(std::ostream& out) const;
};
}

1
src/sat/sat_elim_eqs.cpp
View file

@ -230,6 +230,7 @@ namespace sat {
literal l(v, false);
literal r = roots[v];
SASSERT(v != r.var());
if (m_solver.m_aig_simplifier) m_solver.m_aig_simplifier->set_root(v, r);
bool set_root = m_solver.set_root(l, r);
bool root_ok = !m_solver.is_external(v) || set_root;
if (m_solver.is_assumption(v) || (m_solver.is_external(v) && (m_solver.is_incremental() || !root_ok))) {