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sketch parity generalization

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2022-12-07 20:04:58 -08:00
parent 55d691e16e
commit 437f826e8b
4 changed files with 118 additions and 17 deletions
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41
src/math/dd/dd_pdd.cpp
View file

@ -165,6 +165,47 @@ namespace dd {
return true;
}
unsigned pdd_manager::min_parity(PDD p) {
if (m_semantics != mod2N_e)
return 0;
if (is_val(p)) {
rational v = val(p);
if (v.is_zero())
return m_power_of_2 + 1;
unsigned r = 0;
while (v.is_even() && v > 0)
r++, v /= 2;
return r;
}
PDD q = p;
while (!is_val(q))
q = lo(q);
unsigned p2 = val(q).trailing_zeros();
init_mark();
if (p2 == 0)
return 0;
init_mark();
m_todo.push_back(hi(p));
while (!m_todo.empty() && p2 != 0) {
PDD r = m_todo.back();
m_todo.pop_back();
if (is_marked(r))
continue;
set_mark(r);
if (!is_val(r)) {
m_todo.push_back(lo(r));
m_todo.push_back(hi(r));
}
else if (val(r).is_zero())
continue;
else if (val(r).trailing_zeros() < p2)
p2 = val(r).trailing_zeros();
}
m_todo.reset();
return p2;
}
pdd pdd_manager::subst_val(pdd const& p, pdd const& s) {
return pdd(apply(p.root, s.root, pdd_subst_val_op), this);
}

2
src/math/dd/dd_pdd.h
View file

@ -255,6 +255,7 @@ namespace dd {
inline bool is_var(PDD p) const { return !is_val(p) && is_zero(lo(p)) && is_one(hi(p)); }
inline bool is_max(PDD p) const { SASSERT(m_semantics == mod2_e || m_semantics == mod2N_e); return is_val(p) && val(p) == max_value(); }
bool is_never_zero(PDD p);
unsigned min_parity(PDD p);
inline unsigned level(PDD p) const { return m_nodes[p].m_level; }
inline unsigned var(PDD p) const { return m_level2var[level(p)]; }
inline PDD lo(PDD p) const { return m_nodes[p].m_lo; }
@ -432,6 +433,7 @@ namespace dd {
void get_univariate_coefficients(vector<rational>& coeff) const { m.get_univariate_coefficients(root, coeff); }
vector<rational> get_univariate_coefficients() const { vector<rational> coeff; m.get_univariate_coefficients(root, coeff); return coeff; }
bool is_never_zero() const { return m.is_never_zero(root); }
unsigned min_parity() const { return m.min_parity(root); }
bool var_is_leaf(unsigned v) const { return m.var_is_leaf(root, v); }
pdd operator-() const { return m.minus(*this); }