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sort occurences by the most occured first

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Signed-off-by: Lev Nachmanson <levnach@hotmail.com>
This commit is contained in:
Lev Nachmanson 2019-07-30 12:30:20 -07:00
parent 0ba8940ae7
commit 7cf23c1a32
1 changed files with 28 additions and 39 deletions
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67
src/math/lp/cross_nested.h
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@ -61,7 +61,7 @@ public:
}
};
static bool extract_common_factor(nex* c, nex& f, const std::unordered_map<lpvar, occ> & occurences) {
static bool extract_common_factor(nex* c, nex& f, const vector<std::pair<lpvar, occ>> & occurences) {
TRACE("nla_cn", tout << "c=" << *c << "\n";);
SASSERT(c->is_sum());
f.type() = expr_type::MUL;
@ -97,7 +97,7 @@ public:
return false;
}
bool proceed_with_common_factor(nex* c, vector<nex*>& front, const std::unordered_map<lpvar, occ> & occurences) {
bool proceed_with_common_factor(nex* c, vector<nex*>& front, const vector<std::pair<lpvar, occ>> & occurences) {
TRACE("nla_cn", tout << "c=" << *c << "\n";);
SASSERT(c->is_sum());
nex f;
@ -130,7 +130,7 @@ public:
*(front[i]) = copy[i];
}
void explore_expr_on_front_elem_occs(nex* c, vector<nex*>& front, const std::unordered_map<lpvar, occ> & occurences) {
void explore_expr_on_front_elem_occs(nex* c, vector<nex*>& front, const vector<std::pair<lpvar, occ>> & occurences) {
if (proceed_with_common_factor(c, front, occurences))
return;
TRACE("nla_cn", tout << "save c=" << *c << "; front:"; print_vector_of_ptrs(front, tout) << "\n";);
@ -156,7 +156,8 @@ public:
}
}
static std::ostream& dump_occurences(std::ostream& out, const std::unordered_map<lpvar, occ>& occurences) {
template <typename T>
static std::ostream& dump_occurences(std::ostream& out, const T& occurences) {
out << "{";
for(const auto& p: occurences) {
const occ& o = p.second;
@ -226,6 +227,8 @@ public:
TRACE("nla_cn_details", tout << "occs="; dump_occurences(tout, occurences) << "\n";);
}
static void remove_singular_occurences(std::unordered_map<lpvar, occ>& occurences) {
svector<lpvar> r;
for (const auto & p : occurences) {
@ -236,8 +239,10 @@ public:
for (lpvar j : r)
occurences.erase(j);
}
// j -> the number of expressions j appears in as a multiplier, get the max degree as well
static std::unordered_map<lpvar, occ> get_mult_occurences(const nex& e) {
// j -> the number of expressions j appears in as a multiplier
// The result is sorted by large number of occurences first
static vector<std::pair<lpvar, occ>> get_mult_occurences(const nex& e) {
std::unordered_map<lpvar, occ> occurences;
SASSERT(e.type() == expr_type::SUM);
for (const auto & ce : e.children()) {
@ -249,39 +254,23 @@ public:
}
}
remove_singular_occurences(occurences);
TRACE("nla_cn_details", tout << "e=" << e << "\noccs="; dump_occurences(tout, occurences) << "\n";);
return occurences;
}
static bool can_be_cross_nested_more(const nex& s) {
auto e = s;
e.simplify();
TRACE("nla_cn", tout << "simplified " << e << "\n";);
switch (e.type()) {
case expr_type::SCALAR:
return false;
case expr_type::SUM:
if ( !get_mult_occurences(e).empty()) {
TRACE("nla_cn", tout << "true for " << e << "\n";);
return true;
}
// fall through MUL
case expr_type::MUL:
{
for (const auto & c: e.children()) {
if (can_be_cross_nested_more(c)) {
TRACE("nla_cn", tout << "true for " << e << "\n";);
return true;
}
}
return false;
}
case expr_type::VAR:
return false;
default:
TRACE("nla_cn_details", tout << e.type() << "\n";);
SASSERT(false);
return false;
}
TRACE("nla_cn_details", tout << "e=" << e << "\noccs="; dump_occurences(tout, occurences) << "\n";);
vector<std::pair<lpvar, occ>> ret;
for (auto & p : occurences)
ret.push_back(p);
std::sort(ret.begin(), ret.end(), [](const std::pair<lpvar, occ>& a, const std::pair<lpvar, occ>& b) {
if (a.second.m_occs > b.second.m_occs)
return true;
if (a.second.m_occs < b.second.m_occs)
return false;
if (a.second.m_power > b.second.m_power)
return true;
if (a.second.m_power < b.second.m_power)
return false;
return a.first < b.first;
});
return ret;
}
// all factors of j go to a, the rest to b
static void pre_split(nex &e, lpvar j, nex &a, nex&b) {