Node SharedTermsDatabase::explain(TNode literal) const {
bool polarity = literal.getKind() != kind::NOT;
TNode atom = polarity ? literal : literal[0];
Assert(atom.getKind() == kind::EQUAL);
std::vector<TNode> assumptions;
d_equalityEngine.explainEquality(atom[0], atom[1], polarity, assumptions);
return mkAnd(assumptions);
}
void SharedTermsDatabase::checkForConflict() {
if (d_inConflict) {
d_inConflict = false;
std::vector<TNode> assumptions;
d_equalityEngine.explainEquality(d_conflictLHS, d_conflictRHS, d_conflictPolarity, assumptions);
Node conflict = mkAnd(assumptions);
d_theoryEngine->conflict(conflict, THEORY_BUILTIN);
d_conflictLHS = d_conflictRHS = Node::null();
}
}
Enode * Egraph::canonizeDTC( Enode * formula
, bool split_eqs )
{
assert( config.sat_lazy_dtc != 0 );
assert( config.logic == QF_UFLRA
|| config.logic == QF_UFIDL );
list< Enode * > dtc_axioms;
vector< Enode * > unprocessed_enodes;
initDupMap1( );
unprocessed_enodes.push_back( formula );
//
// Visit the DAG of the formula from the leaves to the root
//
while( !unprocessed_enodes.empty( ) )
{
Enode * enode = unprocessed_enodes.back( );
//
// Skip if the node has already been processed before
//
if ( valDupMap1( enode ) != NULL )
{
unprocessed_enodes.pop_back( );
continue;
}
bool unprocessed_children = false;
Enode * arg_list;
for ( arg_list = enode->getCdr( )
; arg_list != enil
; arg_list = arg_list->getCdr( ) )
{
Enode * arg = arg_list->getCar( );
assert( arg->isTerm( ) );
//
// Push only if it is unprocessed
//
if ( valDupMap1( arg ) == NULL )
{
unprocessed_enodes.push_back( arg );
unprocessed_children = true;
}
}
//
// SKip if unprocessed_children
//
if ( unprocessed_children )
continue;
unprocessed_enodes.pop_back( );
Enode * result = NULL;
//
// Replace arithmetic atoms with canonized version
//
if ( enode->isTAtom( )
&& !enode->isIff( )
&& !enode->isUp( ) )
{
// No need to do anything if node is purely UF
if ( isRootUF( enode ) )
{
if ( config.verbosity > 2 )
cerr << "# Egraph::Skipping canonization of " << enode << " as it's root is purely UF" << endl;
result = enode;
}
else
{
LAExpression a( enode );
result = a.toEnode( *this );
if ( split_eqs && result->isEq( ) )
{
#ifdef PRODUCE_PROOF
if ( config.produce_inter != 0 )
opensmt_error2( "can't compute interpolant for equalities at the moment ", enode );
#endif
LAExpression aa( enode );
Enode * e = aa.toEnode( *this );
Enode * lhs = e->get1st( );
Enode * rhs = e->get2nd( );
Enode * leq = mkLeq( cons( lhs, cons( rhs ) ) );
LAExpression b( leq );
leq = b.toEnode( *this );
Enode * geq = mkGeq( cons( lhs, cons( rhs ) ) );
LAExpression c( geq );
geq = c.toEnode( *this );
Enode * not_e = mkNot( cons( enode ) );
Enode * not_l = mkNot( cons( leq ) );
Enode * not_g = mkNot( cons( geq ) );
// Add clause ( !x=y v x<=y )
Enode * c1 = mkOr( cons( not_e
, cons( leq ) ) );
// Add clause ( !x=y v x>=y )
Enode * c2 = mkOr( cons( not_e
, cons( geq ) ) );
// Add clause ( x=y v !x>=y v !x<=y )
Enode * c3 = mkOr( cons( enode
, cons( not_l
, cons( not_g ) ) ) );
// Add conjunction of clauses
Enode * ax = mkAnd( cons( c1
, cons( c2
, cons( c3 ) ) ) );
dtc_axioms.push_back( ax );
result = enode;
}
}
}
//
// If nothing have been done copy and simplify
//
if ( result == NULL )
result = copyEnodeEtypeTermWithCache( enode );
assert( valDupMap1( enode ) == NULL );
storeDupMap1( enode, result );
}
Enode * new_formula = valDupMap1( formula );
assert( new_formula );
doneDupMap1( );
if ( !dtc_axioms.empty( ) )
{
dtc_axioms.push_back( new_formula );
new_formula = mkAnd( cons( dtc_axioms ) );
}
return new_formula;
}
