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extract/concat in constraint_manager

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This commit is contained in:
Jakob Rath 2023-07-20 17:41:46 +02:00
parent f321811b18
commit e45807db0c
2 changed files with 54 additions and 2 deletions
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52
src/math/polysat/constraint_manager.cpp
View file

@ -440,7 +440,6 @@ namespace polysat {
signed_constraint constraint_manager::find_op(op_constraint::code op, pdd const& p, pdd const& q) const {
auto& m = p.manager();
unsigned sz = m.power_of_2();
op_constraint_args const args(op, p, q);
auto it = m_dedup.op_constraint_expr.find_iterator(args);
@ -476,6 +475,7 @@ namespace polysat {
m_dedup.op_constraint_by_result_var.insert(r.var(), c);
s.add_clause(c, false);
return r;
}
@ -588,10 +588,58 @@ namespace polysat {
return div_rem_op_constraint(p, q).second;
}
pdd constraint_manager::extract(pdd const& p, unsigned hi, unsigned lo) {
SASSERT(hi >= lo);
SASSERT(p.power_of_2() > hi);
if (p.is_val()) {
// p[hi:lo] = (p >> lo) % 2^(hi - lo + 1)
rational q = mod2k(machine_div2k(p.val(), lo), hi - lo + 1);
return p.manager().mk_val(q);
}
if (!lo) {
// TODO: we could push the extract down into variables of the term instead of introducing a name.
}
pvar const src = s.m_names.mk_name(p);
pvar const v = s.m_slicing.mk_extract(src, hi, lo);
return s.var(v);
}
pdd constraint_manager::concat(pdd const& p, pdd const& q) {
// v := p ++ q (new variable of size |p| + |q|)
// v[:|q|] = p
// v[|q|:] = q
unsigned const p_sz = p.power_of_2();
unsigned const q_sz = q.power_of_2();
unsigned const v_sz = p_sz + q_sz;
if (p.is_val() && q.is_val()) {
rational const val = p.val() * rational::power_of_two(q_sz) + q.val();
return s.sz2pdd(v_sz).mk_val(val);
}
if (p.is_val()) {
// TODO
}
if (q.is_val()) {
// TODO
}
auto const args = {p, q};
return concat(args.size(), args.begin());
}
pdd constraint_manager::concat(unsigned num_args, pdd const* args) {
SASSERT(num_args > 0);
if (num_args == 1)
return args[0];
// TODO: special cases when args are values?
pvar_vector pvar_args;
for (unsigned i = 0; i < num_args; ++i)
pvar_args.push_back(s.m_names.mk_name(args[i]));
pvar const v = s.m_slicing.mk_concat(num_args, pvar_args.data());
return s.var(v);
}
/** unsigned quotient/remainder */
std::pair<pdd, pdd> constraint_manager::div_rem_op_constraint(pdd const& a, pdd const& b) {
auto& m = a.manager();
unsigned sz = m.power_of_2();
if (b.is_zero()) {
// By SMT-LIB specification, b = 0 ==> q = -1, r = a.
return {m.mk_val(m.max_value()), a};

4
src/math/polysat/constraint_manager.h
View file

@ -157,6 +157,10 @@ namespace polysat {
pdd udiv(pdd const& a, pdd const& b);
pdd urem(pdd const& a, pdd const& b);
pdd extract(pdd const& p, unsigned hi, unsigned lo);
pdd concat(pdd const& p, pdd const& q);
pdd concat(unsigned num_args, pdd const* args);
constraint* const* begin() const { return m_constraints.data(); }
constraint* const* end() const { return m_constraints.data() + m_constraints.size(); }