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make sure that the returned cross nested form is equal to the original

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Signed-off-by: Lev Nachmanson <levnach@hotmail.com>
This commit is contained in:
Lev Nachmanson 2019-08-19 16:51:52 -07:00
parent 4e59976c2f
commit a844b88c32
3 changed files with 101 additions and 36 deletions
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99
src/math/lp/nex.h
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@ -49,7 +49,7 @@ public:
virtual expr_type type() const = 0;
virtual std::ostream& print(std::ostream&) const = 0;
nex() {}
bool is_simple() const {
bool is_elementary() const {
switch(type()) {
case expr_type::SUM:
case expr_type::MUL:
@ -67,7 +67,10 @@ public:
virtual ~nex() {}
virtual bool contains(lpvar j) const { return false; }
virtual int get_degree() const = 0;
virtual void simplify() {}
virtual void simplify(nex** ) = 0;
virtual bool is_simplified() const {
return true;
}
virtual const ptr_vector<nex> * children_ptr() const {
UNREACHABLE();
return nullptr;
@ -103,6 +106,7 @@ public:
bool contains(lpvar j) const { return j == m_j; }
int get_degree() const { return 1; }
virtual void simplify(nex** e) { *e = this; }
};
class nex_scalar : public nex {
@ -119,29 +123,48 @@ public:
}
int get_degree() const { return 0; }
virtual void simplify(nex** e) { *e = this; }
};
const nex_scalar * to_scalar(const nex* a);
static bool ignored_child(nex* e, expr_type t) {
switch(t) {
case expr_type::MUL:
return e->is_scalar() && to_scalar(e)->value().is_one();
case expr_type::SUM:
return e->is_scalar() && to_scalar(e)->value().is_zero();
default: return false;
}
return false;
}
static void promote_children_by_type(ptr_vector<nex> * children, expr_type t) {
ptr_vector<nex> to_promote;
int skipped = 0;
for(unsigned j = 0; j < children->size(); j++) {
nex* e = (*children)[j];
e->simplify();
if (e->type() == t) {
to_promote.push_back(e);
nex** e = &(*children)[j];
(*e)->simplify(e);
if ((*e)->type() == t) {
to_promote.push_back(*e);
} else if (ignored_child(*e, t)) {
skipped ++;
continue;
} else {
unsigned offset = to_promote.size();
unsigned offset = to_promote.size() + skipped;
if (offset) {
(*children)[j - offset] = e;
(*children)[j - offset] = *e;
}
}
}
children->shrink(children->size() - to_promote.size());
children->shrink(children->size() - to_promote.size() - skipped);
for (nex *e : to_promote) {
for (nex *ee : *(e->children_ptr())) {
children->push_back(ee);
if (!ignored_child(ee, t))
children->push_back(ee);
}
}
}
@ -163,12 +186,12 @@ public:
std::string s = v->str();
if (first) {
first = false;
if (v->is_simple())
if (v->is_elementary())
out << s;
else
out << "(" << s << ")";
} else {
if (v->is_simple()) {
if (v->is_elementary()) {
if (s[0] == '-') {
out << "*(" << s << ")";
} else {
@ -222,12 +245,29 @@ public:
return degree;
}
void simplify() {
void simplify(nex **e) {
*e = this;
TRACE("nla_cn_details", tout << *this << "\n";);
promote_children_by_type(&m_children, expr_type::MUL);
if (size() == 1)
*e = m_children[0];
TRACE("nla_cn_details", tout << *this << "\n";);
SASSERT((*e)->is_simplified());
}
#ifdef Z3DEBUG
virtual bool is_simplified() const {
if (size() < 2)
return false;
for (nex * e : children()) {
if (e->is_mul())
return false;
if (e->is_scalar() && to_scalar(e)->value().is_one())
return false;
}
return true;
}
#ifdef Z3DEBUG
virtual void sort() {
for (nex * c : m_children) {
c->sort();
@ -271,12 +311,12 @@ public:
std::string s = v->str();
if (first) {
first = false;
if (v->is_simple())
if (v->is_elementary())
out << s;
else
out << "(" << s << ")";
} else {
if (v->is_simple()) {
if (v->is_elementary()) {
if (s[0] == '-') {
out << s;
} else {
@ -290,8 +330,21 @@ public:
return out;
}
void simplify() {
void simplify(nex **e) {
*e = this;
promote_children_by_type(&m_children, expr_type::SUM);
if (size() == 1)
*e = m_children[0];
}
virtual bool is_simplified() const {
if (size() < 2) return false;
for (nex * e : children()) {
if (e->is_sum())
return false;
if (e->is_scalar() && to_scalar(e)->value().is_zero())
return false;
}
return true;
}
int get_degree() const {
@ -331,6 +384,11 @@ inline const nex_var* to_var(const nex*a) {
return static_cast<const nex_var*>(a);
}
inline const nex_scalar* to_scalar(const nex*a) {
SASSERT(a->is_scalar());
return static_cast<const nex_scalar*>(a);
}
inline const nex_mul* to_mul(const nex*a) {
SASSERT(a->is_mul());
return static_cast<const nex_mul*>(a);
@ -341,11 +399,6 @@ inline nex_mul* to_mul(nex*a) {
return static_cast<nex_mul*>(a);
}
inline const nex_scalar * to_scalar(const nex* a) {
SASSERT(a->is_scalar());
return static_cast<const nex_scalar*>(a);
}
inline std::ostream& operator<<(std::ostream& out, const nex& e ) {
return e.print(out);
}