/** Performs the DBSCAN algorithm on the given database. */
public Clustering<Model> run(Relation<O> relation) {
final int size = relation.size();
if (size < minpts) {
Clustering<Model> result = new Clustering<>("DBSCAN Clustering", "dbscan-clustering");
result.addToplevelCluster(
new Cluster<Model>(relation.getDBIDs(), true, ClusterModel.CLUSTER));
return result;
}
RangeQuery<O> rangeQuery = QueryUtil.getRangeQuery(relation, getDistanceFunction());
resultList = new ArrayList<>();
noise = DBIDUtil.newHashSet();
runDBSCAN(relation, rangeQuery);
double averagen = ncounter / (double) relation.size();
LOG.statistics(new DoubleStatistic(DBSCAN.class.getName() + ".average-neighbors", averagen));
if (averagen < 1 + 0.1 * (minpts - 1)) {
LOG.warning("There are very few neighbors found. Epsilon may be too small.");
}
if (averagen > 100 * minpts) {
LOG.warning("There are very many neighbors found. Epsilon may be too large.");
}
Clustering<Model> result = new Clustering<>("DBSCAN Clustering", "dbscan-clustering");
for (ModifiableDBIDs res : resultList) {
result.addToplevelCluster(new Cluster<Model>(res, ClusterModel.CLUSTER));
}
result.addToplevelCluster(new Cluster<Model>(noise, true, ClusterModel.CLUSTER));
return result;
}
@Override
public void processNewResult(ResultHierarchy hier, Result newResult) {
// We may just have added this result.
if (newResult instanceof Clustering && isReferenceResult((Clustering<?>) newResult)) {
return;
}
Database db = ResultUtil.findDatabase(hier);
List<Clustering<?>> crs = ResultUtil.getClusteringResults(newResult);
if (crs == null || crs.size() < 1) {
return;
}
// Compute the reference clustering
Clustering<?> refc = null;
// Try to find an existing reference clustering (globally)
{
Collection<Clustering<?>> cs = ResultUtil.filterResults(hier, db, Clustering.class);
for (Clustering<?> test : cs) {
if (isReferenceResult(test)) {
refc = test;
break;
}
}
}
// Try to find an existing reference clustering (locally)
if (refc == null) {
Collection<Clustering<?>> cs = ResultUtil.filterResults(hier, newResult, Clustering.class);
for (Clustering<?> test : cs) {
if (isReferenceResult(test)) {
refc = test;
break;
}
}
}
if (refc == null) {
LOG.debug("Generating a new reference clustering.");
Result refres = referencealg.run(db);
List<Clustering<?>> refcrs = ResultUtil.getClusteringResults(refres);
if (refcrs.size() == 0) {
LOG.warning("Reference algorithm did not return a clustering result!");
return;
}
if (refcrs.size() > 1) {
LOG.warning("Reference algorithm returned more than one result!");
}
refc = refcrs.get(0);
} else {
LOG.debug("Using existing clustering: " + refc.getLongName() + " " + refc.getShortName());
}
for (Clustering<?> c : crs) {
if (c == refc) {
continue;
}
evaluteResult(db, c, refc);
}
}
@Override
public void checkRange(DBIDRange range) {
final int size = max + 1 - min;
if (size < range.size()) {
LOG.warning("Distance matrix has size " + size + " but range has size: " + range.size());
}
}
protected void autoEvaluateClusterings(ResultHierarchy hier, Result newResult) {
Collection<Clustering<?>> clusterings =
ResultUtil.filterResults(hier, newResult, Clustering.class);
if (LOG.isDebugging()) {
LOG.warning("Number of new clustering results: " + clusterings.size());
}
for (Iterator<Clustering<?>> c = clusterings.iterator(); c.hasNext(); ) {
Clustering<?> test = c.next();
if ("allinone-clustering".equals(test.getShortName())) {
c.remove();
} else if ("allinnoise-clustering".equals(test.getShortName())) {
c.remove();
} else if ("bylabel-clustering".equals(test.getShortName())) {
c.remove();
} else if ("bymodel-clustering".equals(test.getShortName())) {
c.remove();
}
}
if (clusterings.size() > 0) {
try {
new EvaluateClustering(new ByLabelClustering(), false, true)
.processNewResult(hier, newResult);
} catch (NoSupportedDataTypeException e) {
// Pass - the data probably did not have labels.
}
}
}
@Override
protected void makeOptions(Parameterization config) {
super.makeOptions(config);
DoubleParameter epsilonP =
new DoubleParameter(EPSILON_ID) //
.addConstraint(CommonConstraints.GREATER_THAN_ZERO_DOUBLE);
if (config.grab(epsilonP)) {
epsilon = epsilonP.getValue();
}
IntParameter minptsP =
new IntParameter(MINPTS_ID) //
.addConstraint(CommonConstraints.GREATER_EQUAL_ONE_INT);
if (config.grab(minptsP)) {
minpts = minptsP.getValue();
if (minpts <= 2) {
LOG.warning(
"DBSCAN with minPts <= 2 is equivalent to single-link clustering at a single height. Consider using larger values of minPts.");
}
}
}
/**
* Run the algorithm.
*
* @param database Database to use
* @param relation Relation to use
* @return Result
*/
public OutlierResult run(Database database, Relation<?> relation) {
WritableDoubleDataStore scores =
DataStoreUtil.makeDoubleStorage(relation.getDBIDs(), DataStoreFactory.HINT_STATIC);
DoubleMinMax minmax = new DoubleMinMax();
try (InputStream in = FileUtil.tryGzipInput(new FileInputStream(file)); //
TokenizedReader reader = CSVReaderFormat.DEFAULT_FORMAT.makeReader()) {
Tokenizer tokenizer = reader.getTokenizer();
CharSequence buf = reader.getBuffer();
Matcher mi = idpattern.matcher(buf), ms = scorepattern.matcher(buf);
reader.reset(in);
while (reader.nextLineExceptComments()) {
Integer id = null;
double score = Double.NaN;
for (
/* initialized by nextLineExceptComments */ ; tokenizer.valid(); tokenizer.advance()) {
mi.region(tokenizer.getStart(), tokenizer.getEnd());
ms.region(tokenizer.getStart(), tokenizer.getEnd());
final boolean mif = mi.find();
final boolean msf = ms.find();
if (mif && msf) {
throw new AbortException(
"ID pattern and score pattern both match value: " + tokenizer.getSubstring());
}
if (mif) {
if (id != null) {
throw new AbortException(
"ID pattern matched twice: previous value "
+ id
+ " second value: "
+ tokenizer.getSubstring());
}
id = Integer.parseInt(buf.subSequence(mi.end(), tokenizer.getEnd()).toString());
}
if (msf) {
if (!Double.isNaN(score)) {
throw new AbortException(
"Score pattern matched twice: previous value "
+ score
+ " second value: "
+ tokenizer.getSubstring());
}
score = ParseUtil.parseDouble(buf, ms.end(), tokenizer.getEnd());
}
}
if (id != null && !Double.isNaN(score)) {
scores.putDouble(DBIDUtil.importInteger(id), score);
minmax.put(score);
} else if (id == null && Double.isNaN(score)) {
LOG.warning(
"Line did not match either ID nor score nor comment: " + reader.getLineNumber());
} else {
throw new AbortException(
"Line matched only ID or only SCORE patterns: " + reader.getLineNumber());
}
}
} catch (IOException e) {
throw new AbortException(
"Could not load outlier scores: " + e.getMessage() + " when loading " + file, e);
}
OutlierScoreMeta meta;
if (inverted) {
meta = new InvertedOutlierScoreMeta(minmax.getMin(), minmax.getMax());
} else {
meta = new BasicOutlierScoreMeta(minmax.getMin(), minmax.getMax());
}
DoubleRelation scoresult =
new MaterializedDoubleRelation(
"External Outlier", "external-outlier", scores, relation.getDBIDs());
OutlierResult or = new OutlierResult(meta, scoresult);
// Apply scaling
if (scaling instanceof OutlierScalingFunction) {
((OutlierScalingFunction) scaling).prepare(or);
}
DoubleMinMax mm = new DoubleMinMax();
for (DBIDIter iditer = relation.iterDBIDs(); iditer.valid(); iditer.advance()) {
double val = scoresult.doubleValue(iditer);
val = scaling.getScaled(val);
scores.putDouble(iditer, val);
mm.put(val);
}
meta = new BasicOutlierScoreMeta(mm.getMin(), mm.getMax());
or = new OutlierResult(meta, scoresult);
return or;
}
protected void autoEvaluateOutliers(ResultHierarchy hier, Result newResult) {
Collection<OutlierResult> outliers =
ResultUtil.filterResults(hier, newResult, OutlierResult.class);
if (LOG.isDebugging()) {
LOG.debug("Number of new outlier results: " + outliers.size());
}
if (outliers.size() > 0) {
Database db = ResultUtil.findDatabase(hier);
ResultUtil.ensureClusteringResult(db, db);
Collection<Clustering<?>> clusterings = ResultUtil.filterResults(hier, db, Clustering.class);
if (clusterings.size() == 0) {
LOG.warning(
"Could not find a clustering result, even after running 'ensureClusteringResult'?!?");
return;
}
Clustering<?> basec = clusterings.iterator().next();
// Find minority class label
int min = Integer.MAX_VALUE;
int total = 0;
String label = null;
if (basec.getAllClusters().size() > 1) {
for (Cluster<?> c : basec.getAllClusters()) {
final int csize = c.getIDs().size();
total += csize;
if (csize < min) {
min = csize;
label = c.getName();
}
}
}
if (label == null) {
LOG.warning("Could not evaluate outlier results, as I could not find a minority label.");
return;
}
if (min == 1) {
LOG.warning(
"The minority class label had a single object. Try using 'ClassLabelFilter' to identify the class label column.");
}
if (min > 0.05 * total) {
LOG.warning(
"The minority class I discovered (labeled '"
+ label
+ "') has "
+ (min * 100. / total)
+ "% of objects. Outlier classes should be more rare!");
}
LOG.verbose("Evaluating using minority class: " + label);
Pattern pat = Pattern.compile("^" + Pattern.quote(label) + "$");
// Evaluate rankings.
new OutlierRankingEvaluation(pat).processNewResult(hier, newResult);
// Compute ROC curve
new OutlierROCCurve(pat).processNewResult(hier, newResult);
// Compute Precision at k
new OutlierPrecisionAtKCurve(pat, min << 1).processNewResult(hier, newResult);
// Compute ROC curve
new OutlierPrecisionRecallCurve(pat).processNewResult(hier, newResult);
// Compute outlier histogram
new ComputeOutlierHistogram(pat, 50, new LinearScaling(), false)
.processNewResult(hier, newResult);
}
}
