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fixes to proof logging and checking

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This commit is contained in:
Nikolaj Bjorner 2022-10-15 12:42:50 +02:00
parent 4388719848
commit 993ff40826
7 changed files with 100 additions and 27 deletions
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34
src/sat/smt/euf_solver.cpp
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@ -200,16 +200,36 @@ namespace euf {
s().assign(lit, sat::justification::mk_ext_justification(s().scope_lvl(), idx));
}
/**
Retrieve set of literals r that imply r.
Since the set of literals are retrieved modulo multiple theories in a single implication
we lose theory specific justifications. For proof logging we use a catch all rule "smt"
for the case where an equality is derived using more than congruence closure.
To create fully decomposed justifications it will be necessary to augment the justification
data-structure with information about the equality that is implied by the theory.
Then each justification will imply an equality s = t assuming literals 'r'.
The theory lemma is then r -> s = t, where s = t is an equality that is available for the EUF hint.
The EUF hint is resolved against r -> s = t to eliminate s = t and to create the resulting explanation.
Example:
x - 3 = 0 => x = 3 by arithmetic
x = 3 => f(x) = f(3) by EUF
resolve to produce clause x - 3 = 0 => f(x) = f(3)
*/
void solver::get_antecedents(literal l, ext_justification_idx idx, literal_vector& r, bool probing) {
m_egraph.begin_explain();
m_explain.reset();
if (use_drat() && !probing)
push(restore_size_trail(m_explain_cc, m_explain_cc.size()));
auto* ext = sat::constraint_base::to_extension(idx);
bool has_theory = false;
if (ext == this)
get_antecedents(l, constraint::from_idx(idx), r, probing);
else
else {
ext->get_antecedents(l, idx, r, probing);
has_theory = true;
}
for (unsigned qhead = 0; qhead < m_explain.size(); ++qhead) {
size_t* e = m_explain[qhead];
if (is_literal(e))
@ -220,10 +240,20 @@ namespace euf {
SASSERT(ext != this);
sat::literal lit = sat::null_literal;
ext->get_antecedents(lit, idx, r, probing);
has_theory = true;
}
}
m_egraph.end_explain();
eq_proof_hint* hint = (use_drat() && !probing) ? mk_hint(l, r) : nullptr;
th_proof_hint* hint = nullptr;
if (use_drat() && !probing) {
if (has_theory) {
r.push_back(~l);
hint = mk_smt_hint(symbol("smt"), r);
r.pop_back();
}
else
hint = mk_hint(l, r);
}
unsigned j = 0;
for (sat::literal lit : r)
if (s().lvl(lit) > 0) r[j++] = lit;