void SVGReader::readDeltaAlpha(void)
{
Q_ASSERT(mXml.isStartElement() && mXml.name() == "deltaalpha");
bool ok = false;
const QString& alphaString = mXml.readElementText();
const int a = alphaString.toInt(&ok);
if (ok)
emit deltaA(a);
else
mXml.raiseError(QObject::tr("invalid delta alpha: %1").arg(alphaString));
}
ExecStatus
AtmostOne::propagate(Space& home, const ModEventDelta&) {
Region r(home);
LubRanges<SetView>* lubs = r.alloc<LubRanges<SetView> >(x.size());
for (int i = x.size(); i--; ) {
lubs[i].init(x[i]);
}
Iter::Ranges::NaryUnion bigT(r, lubs, x.size());
Iter::Ranges::ToValues<Iter::Ranges::NaryUnion>
as(bigT);
while (as()) {
int a = as.val(); ++as;
// cardSa is the number of sets that contain a in the glb
int cardSa = 0;
for (int i=x.size(); i--;)
if (x[i].contains(a))
cardSa++;
// bigTa is the union of all lubs that contain a
GLBndSet bigTa(home);
for (int i=x.size(); i--;) {
if (!x[i].notContains(a)) {
LubRanges<SetView> xilub(x[i]);
bigTa.includeI(home, xilub);
}
}
// maxa is the maximum number of sets that can contain a
int maxa = static_cast<int>((bigTa.size() - 1) / (c - 1));
bigTa.dispose(home);
// Conditional Rule A:
// If more sets already contain a than allowed, fail.
if (maxa < cardSa)
return ES_FAILED;
if (maxa == cardSa) {
// Conditional Rule B:
// All a used up. All other sets (those that don't have a in their
// glb already) cannot contain a.
for (int i=x.size(); i--;) {
if (!x[i].contains(a)) {
GECODE_ME_CHECK(x[i].exclude(home, a));
}
}
} else {
LubRanges<SetView>* lubs2 = r.alloc<LubRanges<SetView> >(x.size());
for (int i = x.size(); i--; ) {
lubs2[i].init(x[i]);
}
Iter::Ranges::NaryUnion bigT2(r, lubs2, x.size());
GlbRanges<SetView>* glbs = r.alloc<GlbRanges<SetView> >(cardSa);
int count = 0;
for (int i=x.size(); i--; ) {
if (x[i].contains(a)) {
glbs[count].init(x[i]);
count++;
}
}
Iter::Ranges::NaryUnion glbsa(r, glbs, cardSa);
Iter::Ranges::Diff<Iter::Ranges::NaryUnion,
Iter::Ranges::NaryUnion> deltaA(bigT2, glbsa);
Iter::Ranges::Cache deltaAC(r,deltaA);
// deltaAC contains all elements that are not yet known to be
// in a set together with a.
// Formally: \cup_i lub(x_i) - \cup_i {glb(s_i) | a\in glb(s_i)}
if (Iter::Ranges::size(deltaAC) == c - 1) {
// Conditional Rule C:
// If deltaA has exactly c-1 elements, all sets that are not yet
// known to contain a cannot contain a if it is impossible that
// they contain all of deltaA. Or the other way around:
// If a is added to the glb of a set s, deltaA must be a subset of
// s, because otherwise s would share at least one more element
// with another set that has a in its lower bound.
// Weird, eh?
for (int i=x.size(); i--; ) {
if (!x[i].contains(a) && !x[i].notContains(a)) {
deltaAC.reset();
LubRanges<SetView> xilub(x[i]);
if (!Iter::Ranges::subset(deltaAC, xilub)) {
GECODE_ME_CHECK(x[i].exclude(home, a));
}
}
}
}
}
}
return ES_NOFIX;
}
