/// <summary>
/// Converts to a <see cref="Distribution"/>.
/// </summary>
/// <returns>The distribution.</returns>
public Distribution ToDistribution()
{
TDigest merged = new TDigest(Accuracy, Compression);
foreach (TDigest dist in PerThreadDist.Values)
{
foreach (DistributionPoint centroid in dist.GetDistribution())
{
merged.Add(centroid.Value, centroid.Count);
}
}
if (merged.CentroidCount > Recompression_Threshold_Factor / Accuracy)
{
merged = Compress(merged);
}
var centroids = merged.GetDistribution()
.Select(centroid => new KeyValuePair <double, int>(
centroid.Value, (int)centroid.Count
))
.ToList();
return(new Distribution(MinuteMillis, centroids));
}
/// <summary>
/// Copy of TDigest's private Compress() method.
/// </summary>
/// <param name="digest"></param>
/// <returns></returns>
private static TDigest Compress(TDigest digest)
{
TDigest newTDigest = new TDigest(Accuracy, Compression);
List <DistributionPoint> temp = digest.GetDistribution().ToList();
temp.Shuffle();
foreach (DistributionPoint centroid in temp)
{
newTDigest.Add(centroid.Value, centroid.Count);
}
return(newTDigest);
}
public void GetsAllDistributionPoints()
{
var digest = new TDigest();
var total = new Random().Next(10, 100);
for (int i = 0; i < total; i++)
{
digest.Add(i);
}
var points = digest.GetDistribution();
Assert.Equal(total, points.Length);
for (int i = 0; i < total; i++)
{
Assert.Equal(i, points[i].Value);
}
}
public void TestSerialization()
{
Random r = new Random();
TDigest digestA = new TDigest();
for (int i = 0; i < 10000; i++)
{
var n = (r.Next() % 50) + (r.Next() % 50);
digestA.Add(n);
}
byte[] s = digestA.Serialize();
TDigest digestB = new TDigest(s);
var a = digestA.GetDistribution();
var b = digestB.GetDistribution();
for (int i = 0; i < a.Length; i++)
{
var ce = a[i].Count == b[i].Count;
var me = a[i].Value == b[i].Value;
Assert.IsTrue(ce && me, "Centroid means or counts are not equal after serialization");
}
Assert.AreEqual(digestA.Average, digestB.Average, "Averages are not equal after serialization");
Assert.AreEqual(digestA.Count, digestB.Count, "Counts are not equal after serialization");
Assert.AreEqual(digestA.CentroidCount, digestB.CentroidCount, "Centroid Counts are not equal after serialization");
Assert.AreEqual(digestA.CompressionConstant, digestB.CompressionConstant, "Compression Constants are not equal after serialization");
Assert.AreEqual(digestA.Accuracy, digestB.Accuracy, "Accuracies are not equal after serialization");
var differences = Enumerable.Range(1, 999)
.Select(n => n / 1000.0)
.Where(q => digestA.Quantile(q) != digestB.Quantile(q))
.Select(q => new { q, A = digestA.Quantile(q), B = digestB.Quantile(q) })
.ToList();
var areEqual = !differences.Any();
Assert.IsTrue(areEqual, "Serialized TDigest is not the same as original");
}
