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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2021-12-11 17:38:09 -08:00
parent 59acd77981
commit f1d46b58a4
5 changed files with 39 additions and 27 deletions
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46
src/math/dd/dd_pdd.cpp
View file

@ -946,40 +946,50 @@ namespace dd {
* result := reduce(v, q*b2*v^{l-m}, b) + reduce(v, a2, b)
*/
pdd pdd_manager::reduce(unsigned v, pdd const& a, pdd const& b) {
unsigned const l = a.degree(v);
unsigned const m = b.degree(v);
// no reduction
if (l < m || m == 0)
if (m == 0)
return a;
pdd a1 = zero();
pdd a2 = zero();
pdd b1 = zero();
pdd b2 = zero();
b.factor(v, m, b1, b2);
// TODO - generalize this case to when leading coefficient is not a value
if (m_semantics == mod2N_e && b1.is_val() && b1.val().is_odd() && !b1.is_one()) {
rational b_inv;
VERIFY(b1.val().mult_inverse(m_power_of_2, b_inv));
b1 = 1;
b2 *= b_inv;
}
return reduce(v, a, m, b1, b2);
}
pdd pdd_manager::reduce(unsigned v, pdd const& a, unsigned m, pdd const& b1, pdd const& b2) {
SASSERT(m > 0);
unsigned const l = a.degree(v);
if (l < m)
return a;
pdd a1 = zero();
pdd a2 = zero();
pdd q = zero();
pdd r = zero();
a.factor(v, l, a1, a2);
b.factor(v, m, b1, b2);
std::cout << "factor v*" << a1 << " ++ " << a2 << "\n";
std::cout << "factor v*" << b1 << " ++ " << b2 << "\n";
quot_rem(a1, b1, q, r);
std::cout << "quot " << q << " rem " << r << "\n";
if (r.is_zero()) {
SASSERT(q * b1 == a1);
a1 = -q * pow(mk_var(v), l - m) * b2;
a1 = -q * b2;
if (l > m)
a1 = reduce(v, a1, b);
a1 = reduce(v, a1 * pow(mk_var(v), l - m), m, b1, b2);
}
else if (m_semantics == mod2N_e && r.is_val() && r.val().is_odd() && q.is_zero()) {
}
else
a1 = a1 * pow(mk_var(v), l);
a2 = a2.reduce(v, b);
else
a1 = a1 * pow(mk_var(v), l);
a2 = reduce(v, a2, m, b1, b2);
pdd result = a1 + a2;
return result;
return a1 + a2;
}
/**

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

@ -280,6 +280,8 @@ namespace dd {
void factor(pdd const& p, unsigned v, unsigned degree, pdd& lc, pdd& rest);
bool factor(pdd const& p, unsigned v, unsigned degree, pdd& lc);
pdd reduce(unsigned v, pdd const& a, unsigned m, pdd const& b1, pdd const& b2);
bool var_is_leaf(PDD p, unsigned v);
bool is_reachable(PDD p);