bool operator()(GroupType const& x, GroupType const& y) const {
if (x->empty() || y->empty())
return true; // doesn't matter if one or both are empty;
if ((*x)[0]->start() < (*y)[0]->start())
return true;
if ((*x)[0]->start() > (*y)[0]->start())
return false;
return (*x)[0]->stop() < (*y)[0]->stop();
}
/**
* Inserts a pair of disjoint elements. Determines whether they can be used to reorder existing sets of lables.
* @param a : One part of pair
* @param b : Other part of pair
* @return : true if a new cluster was required for the insertion.
*/
bool insert(const DisjointElement& a, const DisjointElement& b)
{
const size_t& aLabel = a.getRoot();
const size_t& bLabel = b.getRoot();
bool newItem = true;
GroupType containingAny;
GroupType containingNone;
// ------------- Find equivalent sets
for(GroupType::iterator i = m_groups.begin(); i != m_groups.end(); ++i)
{
GroupType::value_type& cluster =*i;
if(cluster.find(aLabel) != cluster.end())
{
containingAny.push_back(cluster);
}
else if(cluster.find(bLabel) != cluster.end())
{
containingAny.push_back(cluster);
}
else
{
containingNone.push_back(cluster); // Current iterated set contains NEITHER of these labels. It can therfore be ignored.
}
}
// ------------ Process equivalent sets
if(containingAny.empty())
{
// Neither label is yet known to any set. We must add a new set for these
GroupType::value_type newSet;
newSet.insert(aLabel);
newSet.insert(bLabel);
m_groups.push_back(newSet);
}
else
{
// At least one set already contains at least one label. We merge all such sets into a master set.
// implement copy and swap. Rebuild the sets.
GroupType temp = containingNone;
GroupType::value_type masterSet;
masterSet.insert(aLabel); // Incase it doesn't already contain a
masterSet.insert(bLabel); // Incase it doesn't already contain b
for(auto i = containingAny.begin(); i != containingAny.end(); ++i)
{
GroupType::value_type& childSet = *i;
masterSet.insert(childSet.begin(), childSet.end()); // Build the master set.
}
temp.push_back(masterSet);
m_groups = temp; // Swap.
newItem = false;
}
return newItem;
}
