private void OptimalIndexTestCase(
int hilbertTries, int minClusterSize, int maxClusterSize, int dimensions, int clusterCount, int acceptableClusterCount,
int bitsPerDimension, int outlierSize, int noiseSkipBy)
{
var data = new GaussianClustering
{
ClusterCount = clusterCount,
Dimensions = dimensions,
MaxCoordinate = 1000,
MinClusterSize = minClusterSize,
MaxClusterSize = maxClusterSize
};
var clusters = data.MakeClusters();
var points = clusters.Points().Select(p => HilbertPoint.CastOrConvert(p, bitsPerDimension, true)).ToList();
var results = OptimalIndex.Search(
points,
outlierSize,
noiseSkipBy,
hilbertTries, // maxTrials
4 // maxIterationsWithoutImprovement
);
var message = $"Estimated cluster count = {results.EstimatedClusterCount}, actual = {clusterCount}, acceptable = {acceptableClusterCount}";
Console.WriteLine(message);
Assert.LessOrEqual(results.EstimatedClusterCount, acceptableClusterCount, $"HilbertIndex fragmented by more than 50%: {message}");
}
public void AllColorPairsClosestClusterTest(int nPoints, int dimensions, int numClusters, int numCurvesToTry)
{
var rankHistogram = new int[numClusters + 1]; // We will skip the first element so as to have a one-based array.
var data = new GaussianClustering
{
ClusterCount = numClusters,
Dimensions = dimensions,
MaxCoordinate = 1000,
MinClusterSize = nPoints,
MaxClusterSize = nPoints
};
var worstDistanceRatio = 1.0;
var ratioSum = 0.0;
var ratioCount = 0;
var clusters = data.MakeClusters();
var bitsPerDimension = (1 + data.MaxCoordinate).SmallestPowerOfTwo();
var results = OptimalIndex
.Search(
clusters.Points().Select(up => HilbertPoint.CastOrConvert(up, bitsPerDimension, true)).ToList(),
5 /*outlier size */, 10 /* NoiseSkipBy */, 1 /* ReducedNoiseSkipBy */, numCurvesToTry
);
var pccp1 = new PolyChromaticClosestPoint <string>(clusters, results.Index);
var allColorPairs = pccp1.FindAllClustersApproximately();
foreach (var color1 in clusters.ClassLabels())
{
var exact = pccp1.FindClusterExhaustively(color1).Swap(color1);
var color1Pairs = allColorPairs
.Where(cp => cp.Color1.Equals(color1) || cp.Color2.Equals(color1))
.Select(cp => cp.Swap(color1))
.ToList();
var approximateColor2Distance = color1Pairs.First(cp => cp.Color2.Equals(exact.Color2)).SquareDistance;
var approximateRank = color1Pairs.Count(cp => cp.SquareDistance < approximateColor2Distance) + 1;
rankHistogram[approximateRank]++;
#pragma warning disable RECS0018 // Comparison of floating point numbers with equality operator
var ratio = exact.SquareDistance == 0.0 ? 0 : approximateColor2Distance / (double)exact.SquareDistance;
#pragma warning restore RECS0018 // Comparison of floating point numbers with equality operator
ratioSum += ratio;
ratioCount++;
worstDistanceRatio = Math.Max(worstDistanceRatio, ratio);
}
Debug.WriteLine(string.Format("Worst distance overage = {0:N3}%", (worstDistanceRatio - 1.0) * 100.0));
Debug.WriteLine(string.Format("Average distance overage = {0:N3}%", ((ratioSum / ratioCount) - 1.0) * 100.0));
for (var iRank = 1; iRank <= numClusters; iRank++)
{
if (rankHistogram[iRank] > 0 || iRank < 4)
{
Debug.WriteLine(string.Format("For {0} Clusters the closest cluster found was Ranked #{1}.", rankHistogram[iRank], iRank));
}
}
// Accept a win, place or show: the true closest cluster shows up as no worse than the 3rd ranked cluster according to the approximate measure.
Assert.IsTrue(rankHistogram[1] + rankHistogram[2] + rankHistogram[3] == numClusters,
string.Format("Found the closest cluster for {0} colors", rankHistogram[1])
);
}
public void ClosestOfFiftyClusters()
{
int hilbertTries = 1000;
var correctColorCount = 0;
var correctCrosscheckCount = 0;
var correctDistanceCount = 0;
var nPoints = 100;
var dimensions = 100;
var clusterCount = 50;
var data = new GaussianClustering
{
ClusterCount = clusterCount,
Dimensions = dimensions,
MaxCoordinate = 1000,
MinClusterSize = nPoints,
MaxClusterSize = nPoints
};
var closestExact = new PolyChromaticClosestPoint <string> .ClosestPair();
var closestApproximate = new PolyChromaticClosestPoint <string> .ClosestPair();
var bitsPerDimension = (1 + data.MaxCoordinate).SmallestPowerOfTwo();
var clusters = data.MakeClusters();
Assert.AreEqual(clusterCount, clusters.NumPartitions, "Test data are grouped into fewer clusters than requested.");
PolyChromaticClosestPoint <string> pccp;
if (hilbertTries <= 1)
{
pccp = new PolyChromaticClosestPoint <string>(clusters);
}
else
{
var reducedNoiseSkipBy = 1;
var results = OptimalIndex.Search(
clusters.Points().Select(up => HilbertPoint.CastOrConvert(up, bitsPerDimension, true)).ToList(),
5 /*outlier size */, 10 /* NoiseSkipBy */, reducedNoiseSkipBy, hilbertTries
);
pccp = new PolyChromaticClosestPoint <string>(clusters, results.Index);
}
foreach (var color in pccp.Clusters.ClassLabels())
{
var exact = pccp.FindClusterExhaustively(color);
var approximate = pccp.FindClusterApproximately(color);
var crosscheck = pccp.FindClusterIteratively(color);
if (exact.SquareDistance >= approximate.SquareDistance)
{
correctDistanceCount++;
}
if (exact.Color2.Equals(approximate.Color2))
{
correctColorCount++;
}
if (exact.Color2.Equals(crosscheck.Color2))
{
correctCrosscheckCount++;
}
if (exact.SquareDistance < closestExact.SquareDistance)
{
closestExact = exact;
}
if (approximate.SquareDistance < closestApproximate.SquareDistance)
{
closestApproximate = approximate;
}
var ratio = approximate.SquareDistance / (double)exact.SquareDistance;
Console.WriteLine(string.Format("Exact {0} vs Approx. {1} vs Cross {2}. Over by {3:N3}%", exact, approximate, crosscheck, (ratio - 1.0) * 100.0));
}
if (closestExact.SquareDistance >= closestApproximate.SquareDistance)
{
Console.WriteLine("DID FIND the closest pair of points overall. Exact {0}. Approx {1}", closestExact, closestApproximate);
}
else
{
Console.WriteLine("DID NOT FIND the closest pair of points overall. Exact {0}. Approx {1}", closestExact, closestApproximate);
}
Assert.IsTrue(correctColorCount == clusterCount && correctDistanceCount == clusterCount,
string.Format("Of {0} clusters, only {1} searches found the closest cluster and {2} found the shortest distance. Crosscheck = {3}",
clusterCount,
correctColorCount,
correctDistanceCount,
correctCrosscheckCount
)
);
}
public void ClosestClusterTest(int nPoints, int dimensions, int numClusters, int numCurvesToTry, int numCurvesToKeep)
{
var correctColorCount = 0;
var correctDistanceCount = 0;
var data = new GaussianClustering
{
ClusterCount = numClusters,
Dimensions = dimensions,
MaxCoordinate = 1000,
MinClusterSize = nPoints,
MaxClusterSize = nPoints
};
var closestExact = new PolyChromaticClosestPoint <string> .ClosestPair();
var closestApproximate = new PolyChromaticClosestPoint <string> .ClosestPair();
var clusters = data.MakeClusters();
var pccps = new List <PolyChromaticClosestPoint <string> >();
var bitsPerDimension = (1 + data.MaxCoordinate).SmallestPowerOfTwo();
var bestIndices = OptimalIndex.SearchMany(
clusters.Points().Select(up => HilbertPoint.CastOrConvert(up, bitsPerDimension, true)).ToList(),
numCurvesToKeep,
5 /*outlier size */, 10 /* NoiseSkipBy */, 1 /* ReducedNoiseSkipBy */, numCurvesToTry
);
//var pointLists = bestIndices.Select(result => result.Index.SortedPoints).ToList();
//foreach (var pList in pointLists)
// pccps.Add(new PolyChromaticClosestPoint<string>(clusters, pList));
var indices = bestIndices.Select(result => result.Index).ToList();
foreach (var index in indices)
{
pccps.Add(new PolyChromaticClosestPoint <string>(clusters, index));
}
var pccp1 = pccps[0];
foreach (var color in pccp1.Clusters.ClassLabels())
{
var exact = pccp1.FindClusterExhaustively(color);
var approximate = pccps.Select(pccp => pccp.FindClusterApproximately(color)).OrderBy(cp => cp).First();
if (exact.SquareDistance >= approximate.SquareDistance)
{
correctDistanceCount++;
}
if (exact.Color2.Equals(approximate.Color2))
{
correctColorCount++;
}
if (exact.SquareDistance < closestExact.SquareDistance)
{
closestExact = exact;
}
if (approximate.SquareDistance < closestApproximate.SquareDistance)
{
closestApproximate = approximate;
}
var ratio = approximate.SquareDistance / (double)exact.SquareDistance;
Console.WriteLine(string.Format("Exact {0} vs Approx. {1}. Over by {2:N3}%", exact, approximate, (ratio - 1.0) * 100.0));
}
if (closestExact.SquareDistance >= closestApproximate.SquareDistance)
{
Console.WriteLine("DID FIND the closest pair of points overall. Exact {0}. Approx {1}", closestExact, closestApproximate);
}
else
{
Console.WriteLine("DID NOT FIND the closest pair of points overall. Exact {0}. Approx {1}", closestExact, closestApproximate);
}
Assert.IsTrue(correctColorCount == numClusters && correctDistanceCount == numClusters,
string.Format("Of {0} clusters, only {1} searches found the closest cluster and {2} found the shortest distance.",
numClusters,
correctColorCount,
correctDistanceCount
)
);
}
/// <summary>
/// A test case for PolyChromaticClosestPoint.FindPairApproximately where clusters conform to a Gaussian distribution.
/// </summary>
/// <param name="nPoints">Number of points in each cluster.</param>
/// <param name="dimensions">Number of Dimensions in each point.</param>
/// <param name="numClusters">Number of clusters to create.</param>
/// <param name="hilbertsToTry">Number of randomly generated Hilbert curves to try.</param>
public void GaussianPolyChromaticPairTestCase(int nPoints, int dimensions, int numClusters, int hilbertsToTry = 1)
{
var successes = 0;
var worstRatio = 1.0;
var color1 = "0";
var data = new GaussianClustering
{
ClusterCount = numClusters,
Dimensions = dimensions,
MaxCoordinate = 1000,
MinClusterSize = nPoints,
MaxClusterSize = nPoints
};
var clusters = data.MakeClusters();
PolyChromaticClosestPoint <string> pccp;
if (hilbertsToTry <= 1)
{
pccp = new PolyChromaticClosestPoint <string>(clusters);
}
else
{
var bitsPerDimension = (1 + data.MaxCoordinate).SmallestPowerOfTwo();
var results = OptimalIndex.Search(
clusters.Points().Select(up => HilbertPoint.CastOrConvert(up, bitsPerDimension, true)).ToList(),
5 /*outlier size */, 10 /* NoiseSkipBy */, 1 /* ReducedNoiseSkipBy */, hilbertsToTry
);
pccp = new PolyChromaticClosestPoint <string>(clusters, results.Index);
}
for (var iColor2 = 1; iColor2 < numClusters; iColor2++)
{
var color2 = iColor2.ToString();
var exact = pccp.FindPairExhaustively(color1, color2);
var approximate = pccp.FindPairApproximately(color1, color2);
var expectedDistance = exact.SquareDistance;
var actualDistance = approximate.SquareDistance;
if (actualDistance <= expectedDistance)
{
successes++;
}
else
{
worstRatio = Math.Max(worstRatio, actualDistance / (double)expectedDistance);
}
if (exact.SquareDistance >= approximate.SquareDistance)
{
Console.WriteLine("FindPairApproximately CORRECT. Exact {0}. Approx {1}", exact, approximate);
}
else
{
Console.WriteLine("FindPairApproximately INCORRECT. Exact {0}. Approx {1}. Too high by {2:N3}%",
exact, approximate, 100.0 * (approximate.SquareDistance / (double)exact.SquareDistance - 1.0));
}
}
Assert.AreEqual(numClusters - 1, successes,
string.Format("Did not succeed every time. Failed {0} of {1} times. Worst distance ratio is {2:N4}. {3} points of {4} dimensions.",
numClusters - successes - 1,
numClusters - 1,
worstRatio,
nPoints,
dimensions
)
);
}
public void DistanceDistribution()
{
/*
* Percentile,By Index,By Random
* -----------------------------
* 0%,111.35,146.55
* 1%,142.06,255.96
* 2%,147.21,2163.43
* 3%,151.2,2214.15
* 4%,154.06,2245.2
* 5%,156.24,2271.37
* 6%,158.38,2292.29
* 7%,160.42,2313.55
* 8%,162.29,2327.14
* 9%,164.07,2345.25
* 10%,165.41,2359.95
* 11%,166.72,2372.83
* 12%,167.99,2386.15
* 13%,169.29,2398.47
* 14%,170.43,2410.01
* 15%,171.53,2422.34
* 16%,172.48,2432.43
* 17%,173.58,2443.08
* 18%,174.73,2454.27
* 19%,175.56,2463.71
* 20%,176.35,2472.97
* 21%,177.35,2483.24
* 22%,178.3,2491.9
* 23%,179.1,2501.44
* 24%,179.82,2510.26
* 25%,180.64,2517.73
* 26%,181.55,2524.97
* 27%,182.33,2531.58
* 28%,182.98,2538.08
* 29%,183.67,2543.83
* 30%,184.33,2550.93
* 31%,185.09,2556.59
* 32%,185.7,2563.37
* 33%,186.41,2570.29
* 34%,187.09,2577.29
* 35%,187.7,2583.56
* 36%,188.43,2589.95
* 37%,189.07,2596.13
* 38%,189.71,2602.24
* 39%,190.46,2608.28
* 40%,191.08,2615.25
* 41%,191.79,2620.81
* 42%,192.46,2626.02
* 43%,193.09,2632.7
* 44%,193.71,2638.18
* 45%,194.31,2643.35
* 46%,194.98,2648.69
* 47%,195.65,2655.47
* 48%,196.3,2660.26
* 49%,196.96,2666.37
* 50%,197.66,2670.94
* 51%,198.34,2677.09
* 52%,199.07,2681.9
* 53%,199.72,2687.11
* 54%,200.3,2692.42
* 55%,201.06,2697.92
* 56%,201.71,2703.76
* 57%,202.4,2710.17
* 58%,203.16,2715.06
* 59%,203.82,2720.25
* 60%,204.51,2725.99
* 61%,205.32,2731.6
* 62%,206.08,2736.59
* 63%,206.79,2741.72
* 64%,207.58,2746.59
* 65%,208.29,2754.03
* 66%,209.07,2760.81
* 67%,209.8,2766.65
* 68%,210.68,2771.98
* 69%,211.71,2778.27
* 70%,212.38,2784.23
* 71%,213.19,2790.71
* 72%,213.92,2796.42
* 73%,214.82,2802.84
* 74%,215.68,2809.36
* 75%,216.54,2814.55
* 76%,217.48,2821.32
* 77%,218.43,2827.56
* 78%,219.35,2833.35
* 79%,220.28,2840.72
* 80%,221.33,2848.87
* 81%,222.31,2856.89
* 82%,223.42,2864
* 83%,224.46,2872.51
* 84%,225.83,2881.09
* 85%,227.06,2891.57
* 86%,228.27,2900.46
* 87%,229.63,2910.46
* 88%,231.55,2919.5
* 89%,233.59,2933.76
* 90%,235.6,2944.88
* 91%,237.25,2959.45
* 92%,239.83,2976.08
* 93%,241.88,2990.4
* 94%,244.97,3010.08
* 95%,248.23,3029.15
* 96%,252.34,3052.37
* 97%,260.68,3074.84
* 98%,282.76,3112.43 *** Note the jump from 282 to 2550, which shows that the characteristic distance is about 282.
* 99%,2550.87,3170.93
* 100%,3114.89,3412.57
*/
var data = new GaussianClustering
{
ClusterCount = 100,
Dimensions = 50,
MaxCoordinate = 1000,
MinClusterSize = 50,
MaxClusterSize = 150
};
var clusters = data.MakeClusters();
var bitsPerDimension = 10;
var points = clusters.Points().Select(p => HilbertPoint.CastOrConvert(p, bitsPerDimension, true)).ToList();
var results = OptimalIndex.Search(
points,
5, // outlierSize
10, // noiseSkipBy
1000, // maxTrials
4 // maxIterationsWithoutImprovement
);
var pointsFromIndex = results.Index.SortedPoints;
var distancesRandom = new List <long>();
var distancesHilbert = new List <long>();
var n = pointsFromIndex.Count;
var rng = new FastRandom();
for (var i = 0; i < n - 1; i++)
{
var p1 = pointsFromIndex[i];
var p2 = pointsFromIndex[i + 1];
distancesHilbert.Add(p1.Measure(p2));
var p3 = pointsFromIndex[rng.Next(n)];
var p4 = pointsFromIndex[rng.Next(n)];
distancesRandom.Add(p3.Measure(p4));
}
distancesHilbert.Sort();
distancesRandom.Sort();
Console.WriteLine("Percentile,By Index,By Random");
for (var percentile = 0; percentile <= 100; percentile++)
{
var i = Math.Min(n - 2, (n - 1) * percentile / 100);
var distHilbert = Math.Round(Math.Sqrt(distancesHilbert[i]), 2);
var distRandom = Math.Round(Math.Sqrt(distancesRandom[i]), 2);
Console.Write($"{percentile}%,{distHilbert},{distRandom}");
}
}
