void TrainTransform()
{
lock (_lock)
{
if (_Results != null)
{
return;
}
using (var ch = _host.Start("Optics"))
{
var sw = Stopwatch.StartNew();
sw.Start();
var points = new List <IPointIdFloat>();
var index = SchemaHelper.GetColumnIndexDC(_input.Schema, _args.features);
// Caching data.
ch.Info(MessageSensitivity.None, "Caching the data.");
using (var cursor = _input.GetRowCursor(_input.Schema.Where(c => c.Index == index.Index)))
{
var getter = cursor.GetGetter <VBuffer <float> >(index);
var getterId = cursor.GetIdGetter();
DataViewRowId id = new DataViewRowId();
VBuffer <float> tmp = new VBuffer <float>();
for (int i = 0; cursor.MoveNext(); i++)
{
getter(ref tmp);
getterId(ref id);
points.Add(new PointIdFloat((long)id.Low, tmp.DenseValues().Select(c => (float)c)));
}
}
// Mapping.
// int: index of a cluster
// long: index of a point
var mapping = new int[points.Count];
var mapprev = new Dictionary <long, int>();
float[] distances = null;
if (_args.epsilons == null || _args.epsilons.Count() == 0)
{
float mind, maxd;
distances = new[] { EstimateDistance(ch, points, out mind, out maxd) };
ch.Info(MessageSensitivity.UserData, "epsilon (=Radius) was estimating on random couples of points: {0} in [{1}, {2}]", distances.First(), mind, maxd);
}
else
{
distances = _args.epsilonsDouble;
}
var maxEpsilon = distances.Max();
_Results = new List <Dictionary <int, ClusteringResult> >();
_reversedMapping = new List <Dictionary <long, int> >();
Optics opticsAlgo = new Optics(points, _args.seed);
//Ordering
ch.Info(MessageSensitivity.UserData, "Generating OPTICS ordering for {0} points.", points.Count);
int nPoints = points.Count;
int cyclesBetweenLogging = Math.Min(1000, nPoints / 10);
int currentIteration = 0;
Action progressLogger = () =>
{
if (++currentIteration % cyclesBetweenLogging == 0)
{
ch.Info(MessageSensitivity.UserData, "Processing {0}/{1}", currentIteration, nPoints);
}
};
OpticsOrdering opticsOrdering = opticsAlgo.Ordering(
maxEpsilon,
_args.minPoints,
seed: _args.seed,
onShuffle: msg => ch.Info(MessageSensitivity.UserData, msg),
onPointProcessing: progressLogger);
// Clustering.
foreach (var epsilon in distances)
{
ch.Info(MessageSensitivity.UserData, "Clustering {0} points using epsilon={1}.", points.Count, epsilon);
Dictionary <long, int> results = opticsOrdering.Cluster(epsilon);
HashSet <int> clusterIds = new HashSet <int>();
for (int i = 0; i < results.Count; ++i)
{
var p = points[i];
int cluster = results[p.id];
mapprev[p.id] = cluster;
mapping[i] = cluster;
if (cluster != DBScan.NOISE)
{
clusterIds.Add(cluster);
}
}
_reversedMapping.Add(mapprev);
// Cleaning small clusters.
ch.Info(MessageSensitivity.UserData, "Removing clusters with less than {0} points.", _args.minPoints);
var finalCounts_ = results.GroupBy(c => c.Value, (key, g) => new { key = key, nb = g.Count() });
var finalCounts = finalCounts_.ToDictionary(c => c.key, d => d.nb);
results = results.Select(c => new KeyValuePair <long, int>(c.Key, finalCounts[c.Value] < _args.minPoints ? -1 : c.Value))
.ToDictionary(c => c.Key, c => c.Value);
// Cleaning.
ch.Info(MessageSensitivity.None, "Cleaning.");
// We replace by the original labels.
var runResults = new Dictionary <int, ClusteringResult>();
for (int i = 0; i < results.Count; ++i)
{
runResults[i] = new ClusteringResult()
{
cl = results[i] != DBScan.NOISE ? results[i] : -1,
score = results[i] != DBScan.NOISE ? 1f : 0f
};
}
_Results.Add(runResults);
ch.Info(MessageSensitivity.UserData, "Found {0} clusters.", clusterIds.Count);
}
sw.Stop();
ch.Info(MessageSensitivity.UserData, "'Optics' finished in {0}.", sw.Elapsed);
}
}
}
void TrainTransform()
{
lock (_lock)
{
if (_Results != null)
{
return;
}
using (var ch = _host.Start("Starting Optics"))
{
var sw = Stopwatch.StartNew();
sw.Start();
var points = new List <IPointIdFloat>();
int index;
if (!_input.Schema.TryGetColumnIndex(_args.features, out index))
{
ch.Except("Unable to find column '{0}'", _args.features);
}
// Caching data.
ch.Info("Caching the data.");
using (var cursor = _input.GetRowCursor(i => i == index))
{
var getter = cursor.GetGetter <VBuffer <float> >(index);
var getterId = cursor.GetIdGetter();
UInt128 id = new UInt128();
VBuffer <float> tmp = new VBuffer <float>();
for (int i = 0; cursor.MoveNext(); i++)
{
getter(ref tmp);
getterId(ref id);
if (id > long.MaxValue)
{
ch.Except("An id is outside the range for long {0}", id);
}
points.Add(new PointIdFloat((long)id, tmp.DenseValues().Select(c => (float)c)));
}
}
// Mapping.
// long: index in the ordering
// long: index of a point
var mapping = new long[points.Count];
var mapprev = new Dictionary <long, long>();
var distance = (float)_args.epsilon;
if (distance <= 0)
{
float mind, maxd;
distance = EstimateDistance(ch, points, out mind, out maxd);
ch.Info("epsilon (=Radius) was estimating on random couples of points: {0} in [{1}, {2}]", distance, mind, maxd);
}
Optics opticsAlgo = new Optics(points, _args.seed);
//Ordering
ch.Info("Generating OPTICS ordering for {0} points.", points.Count);
int nPoints = points.Count;
int cyclesBetweenLogging = Math.Min(1000, nPoints / 10);
int currentIteration = 0;
Action progressLogger = () =>
{
if (++currentIteration % cyclesBetweenLogging == 0)
{
ch.Info("Processing {0}/{1}", currentIteration, nPoints);
}
};
OpticsOrdering opticsOrdering = opticsAlgo.Ordering(
distance,
_args.minPoints,
seed: _args.seed,
onShuffle: msg => ch.Info(msg),
onPointProcessing: progressLogger);
IReadOnlyDictionary <long, long> results = opticsOrdering.orderingMapping;
var reachabilityDs = opticsOrdering.reachabilityDistances;
var coreDs = opticsOrdering.coreDistancesCache;
for (int i = 0; i < results.Count; ++i)
{
var p = points[i];
mapprev[results[i]] = i;
mapping[i] = results[i];
}
_reversedMapping = mapprev;
// Cleaning.
ch.Info("Cleaning.");
// We replace by the original labels.
_Results = new OpticsOrderingResult[results.Count];
for (int i = 0; i < results.Count; ++i)
{
long pId = points[i].id;
float?rd;
float?cd;
reachabilityDs.TryGetValue(pId, out rd);
coreDs.TryGetValue(pId, out cd);
_Results[i] = new OpticsOrderingResult()
{
id = results[i] != DBScan.NOISE ? results[i] : -1,
reachability = (float)rd.GetValueOrDefault(float.PositiveInfinity),
core = (float)cd.GetValueOrDefault(float.PositiveInfinity)
};
}
ch.Info("Ordered {0} points.", _Results.Count());
sw.Stop();
ch.Info("'OpticsOrdering' finished in {0}.", sw.Elapsed);
}
}
}
