void CompleteLinkage::operator()(DistanceMatrix<float> & original_distance, std::vector<BinaryTreeNode> & cluster_tree, const float threshold /*=1*/) const
{
// attention: clustering process is done by clustering the indices
// pointing to elements in inputvector and distances in inputmatrix
// input MUST have >= 2 elements!
if (original_distance.dimensionsize() < 2)
{
throw ClusterFunctor::InsufficientInput(__FILE__, __LINE__, OPENMS_PRETTY_FUNCTION, "Distance matrix to start from only contains one element");
}
std::vector<std::set<Size> > clusters(original_distance.dimensionsize());
for (Size i = 0; i < original_distance.dimensionsize(); ++i)
{
clusters[i].insert(i);
}
cluster_tree.clear();
cluster_tree.reserve(original_distance.dimensionsize() - 1);
// Initial minimum-distance pair
original_distance.updateMinElement();
std::pair<Size, Size> min = original_distance.getMinElementCoordinates();
Size overall_cluster_steps(original_distance.dimensionsize());
startProgress(0, original_distance.dimensionsize(), "clustering data");
while (original_distance(min.first, min.second) < threshold)
{
//grow the tree
cluster_tree.push_back(BinaryTreeNode(*(clusters[min.second].begin()), *(clusters[min.first].begin()), original_distance(min.first, min.second)));
if (cluster_tree.back().left_child > cluster_tree.back().right_child)
{
std::swap(cluster_tree.back().left_child, cluster_tree.back().right_child);
}
if (original_distance.dimensionsize() > 2)
{
//pick minimum-distance pair i,j and merge them
//pushback elements of second to first (and then erase second)
clusters[min.second].insert(clusters[min.first].begin(), clusters[min.first].end());
// erase first one
clusters.erase(clusters.begin() + min.first);
//update original_distance matrix
//complete linkage: new distance between clusters is the minimum distance between elements of each cluster
//lance-williams update for d((i,j),k): 0.5* d(i,k) + 0.5* d(j,k) + 0.5* |d(i,k)-d(j,k)|
for (Size k = 0; k < min.second; ++k)
{
float dik = original_distance.getValue(min.first, k);
float djk = original_distance.getValue(min.second, k);
original_distance.setValueQuick(min.second, k, (0.5f * dik + 0.5f * djk + 0.5f * std::fabs(dik - djk)));
}
for (Size k = min.second + 1; k < original_distance.dimensionsize(); ++k)
{
float dik = original_distance.getValue(min.first, k);
float djk = original_distance.getValue(min.second, k);
original_distance.setValueQuick(k, min.second, (0.5f * dik + 0.5f * djk + 0.5f * std::fabs(dik - djk)));
}
//reduce
original_distance.reduce(min.first);
//update minimum-distance pair
original_distance.updateMinElement();
//get new min-pair
min = original_distance.getMinElementCoordinates();
}
else
{
break;
}
setProgress(overall_cluster_steps - original_distance.dimensionsize());
//repeat until only two cluster remains or threshold exceeded, last step skips matrix operations
}
//fill tree with dummy nodes
Size sad(*clusters.front().begin());
for (Size i = 1; i < clusters.size() && (cluster_tree.size() < cluster_tree.capacity()); ++i)
{
cluster_tree.push_back(BinaryTreeNode(sad, *clusters[i].begin(), -1.0));
}
//~ while(cluster_tree.size() < cluster_tree.capacity())
//~ {
//~ cluster_tree.push_back(BinaryTreeNode(0,1,-1.0));
//~ }
endProgress();
}
void AverageLinkage::operator()(DistanceMatrix<float> & original_distance, std::vector<BinaryTreeNode> & cluster_tree, const float threshold /*=1*/) const
{
// input MUST have >= 2 elements!
if (original_distance.dimensionsize() < 2)
{
throw ClusterFunctor::InsufficientInput(__FILE__, __LINE__, OPENMS_PRETTY_FUNCTION, "Distance matrix to start from only contains one element");
}
std::vector<std::set<Size> > clusters(original_distance.dimensionsize());
for (Size i = 0; i < original_distance.dimensionsize(); ++i)
{
clusters[i].insert(i);
}
cluster_tree.clear();
cluster_tree.reserve(original_distance.dimensionsize() - 1);
// Initial minimum-distance pair
original_distance.updateMinElement();
std::pair<Size, Size> min = original_distance.getMinElementCoordinates();
Size overall_cluster_steps(original_distance.dimensionsize());
startProgress(0, original_distance.dimensionsize(), "clustering data");
while (original_distance(min.second, min.first) < threshold)
{
//grow the tree
cluster_tree.push_back(BinaryTreeNode(*(clusters[min.second].begin()), *(clusters[min.first].begin()), original_distance(min.first, min.second)));
if (cluster_tree.back().left_child > cluster_tree.back().right_child)
{
std::swap(cluster_tree.back().left_child, cluster_tree.back().right_child);
}
if (original_distance.dimensionsize() > 2)
{
//pick minimum-distance pair i,j and merge them
//calculate parameter for lance-williams formula
float alpha_i = (float)(clusters[min.first].size() / (float)(clusters[min.first].size() + clusters[min.second].size()));
float alpha_j = (float)(clusters[min.second].size() / (float)(clusters[min.first].size() + clusters[min.second].size()));
//~ std::cout << alpha_i << '\t' << alpha_j << std::endl;
//pushback elements of second to first (and then erase second)
clusters[min.second].insert(clusters[min.first].begin(), clusters[min.first].end());
// erase first one
clusters.erase(clusters.begin() + min.first);
//update original_distance matrix
//average linkage: new distance between clusters is the minimum distance between elements of each cluster
//lance-williams update for d((i,j),k): (m_i/m_i+m_j)* d(i,k) + (m_j/m_i+m_j)* d(j,k) ; m_x is the number of elements in cluster x
for (Size k = 0; k < min.second; ++k)
{
float dik = original_distance.getValue(min.first, k);
float djk = original_distance.getValue(min.second, k);
original_distance.setValueQuick(min.second, k, (alpha_i * dik + alpha_j * djk));
}
for (Size k = min.second + 1; k < original_distance.dimensionsize(); ++k)
{
float dik = original_distance.getValue(min.first, k);
float djk = original_distance.getValue(min.second, k);
original_distance.setValueQuick(k, min.second, (alpha_i * dik + alpha_j * djk));
}
//reduce
original_distance.reduce(min.first);
//update minimum-distance pair
original_distance.updateMinElement();
//get min-pair from triangular matrix
min = original_distance.getMinElementCoordinates();
}
else
{
break;
}
setProgress(overall_cluster_steps - original_distance.dimensionsize());
//repeat until only two cluster remains, last step skips matrix operations
}
//fill tree with dummy nodes
Size sad(*clusters.front().begin());
for (Size i = 1; (i < clusters.size()) && (cluster_tree.size() < cluster_tree.capacity()); ++i)
{
cluster_tree.push_back(BinaryTreeNode(sad, *clusters[i].begin(), -1.0));
}
endProgress();
}