/**
* Compare approximate and exact diameter computation. Approximate is very fast but provides only
* a rough upper bound. For a discretized pairwise distance distribution, this is absolutely
* sufficient.
*/
public void testMaxPhaseSpaceDiameter() {
int tsLen = 25000;
TimeSeriesGenerator tsg = new TimeSeriesGenerator(1, tsLen, "lorenz");
double[][][][] trajectories = tsg.getAllTrajectories();
double[][] ts = trajectories[4][0];
System.out.println("Computing max phase space diameter.");
long tic = System.currentTimeMillis();
double diam = PhaseSpaceDistribution.maxPhaseSpaceDiameter(ts, ts);
System.out.println("diam = " + diam);
long toc = System.currentTimeMillis();
System.out.println(toc - tic);
System.out.println("Computing max phase space diameter, approximate.");
tic = System.currentTimeMillis();
double diamApprox = PhaseSpaceDistribution.maxPhaseSpaceDiameterApproximate(ts);
System.out.println("diamApprox = " + diamApprox);
toc = System.currentTimeMillis();
System.out.println(toc - tic);
System.out.println("Relative error: " + (Math.abs(diamApprox - diam) / diam));
// GeometryFactory factory = new GeometryFactory(new
// PrecisionModel(PrecisionModel.FIXED));
// Point[] points = new Point[tsLen];
// for (int i = 0; i < tsLen; i++) {
// Coordinate[] coordinates = new Coordinate[ts.length];
// for (int j = 0; j < ts.length; j++) {
// coordinates[j] = new Co
// }
// points[i] = new Point(new CoordinateArraySequence(coordinates), factory);
// }
// MultiPoint data = new MultiPoint(points, factory);
// MinimumDiameter minimumDiameter = new MinimumDiameter(geom);
}
public void testPhaseSpaceApproxDistribution() {
int tsLen = 500;
TimeSeriesGenerator tsg = new TimeSeriesGenerator(1, tsLen, null);
double[][][][] trajectories = tsg.getAllTrajectories();
for (int systemIdx = 0; systemIdx < 9; systemIdx++) {
double[][] ts = trajectories[systemIdx][0];
long[] dist = PhaseSpaceDistribution.approximateDistanceDistribution(ts);
System.out.println(Arrays.toString(dist));
}
}
private static String processFile(File file) throws IOException {
final String absolutePath = file.getAbsolutePath();
final String filename = file.getName();
System.out.println(String.format("Processing: %s", absolutePath));
double[][] trajectory = BaseExecutable.readFile(absolutePath, ",");
double[][] noisyTrajectory = TimeSeriesGenerator.addNoise(trajectory, 0.05, 0.1);
PhaseSpaceReconstructed phaseSpaceReconstructed =
new PhaseSpaceReconstructed(noisyTrajectory[0], 1);
return String.format(
"%s\t%s\t%s\t%s\t%s",
filename,
filename.split("\\.")[0].subSequence(6, filename.split("\\.")[0].length() - 2),
phaseSpaceReconstructed.embedding_dimension,
phaseSpaceReconstructed.embedding_delay,
phaseSpaceReconstructed.min_embedding_delay);
}
public void testClustering() {
final int numberOfTimeSeriesPerClass = 100;
final int timeSeriesLength = 1500;
final int sample_size = (9 * numberOfTimeSeriesPerClass) / 2;
final int numberOfResamples = 100;
final int maxIterations = 1000;
final int numberOfInitializations = 100;
// ------------------------------------
// compute DRQA measures
// ------------------------------------
TimeSeriesGenerator timeSeriesGenerator =
new TimeSeriesGenerator(numberOfTimeSeriesPerClass, timeSeriesLength, null);
ArrayList<DoublePoint> rqa_measures =
new ArrayList<DoublePoint>(9 * numberOfTimeSeriesPerClass);
System.out.println("Computing DRQA measures");
double[][][][] trajectories = timeSeriesGenerator.getAllTrajectories();
for (int system_idx = 0; system_idx < trajectories.length; system_idx++) {
System.out.println(String.format("System: %s", TimeSeriesGenerator.system_names[system_idx]));
double[][][] trajectory1 = trajectories[system_idx];
for (double[][] trajectory : trajectory1) {
DRQA drqa = new DRQA(trajectory, trajectory, 0.05);
drqa.computeRQA(2, 2, 2);
// rqa_measures[system_idx * numberOfTimeSeriesPerClass + i] = new
// DoublePoint(drqa.allRQAMeasures(DRQA.HistogramStatistic.values()));
rqa_measures.add(new DoublePoint(drqa.standardRQAMeasures()));
}
}
System.out.println(
String.format(
"Standard RQA of first point:\n%s", Arrays.toString(rqa_measures.get(0).getPoint())));
// ------------------------------------
// Cluster
// ------------------------------------
long before = System.currentTimeMillis();
RandomDataGenerator randomDataGenerator = new RandomDataGenerator();
final EuclideanDistance euclideanDistance = new EuclideanDistance();
ClusterEvaluator<DoublePoint> evaluator =
new SumOfClusterVariances<DoublePoint>(euclideanDistance);
ArrayList<DoublePoint> sample = new ArrayList<DoublePoint>(sample_size);
System.out.println(String.format("sample_size: %s", sample_size));
// generate random subsamples of the data set
for (int resample_idx = 0; resample_idx < numberOfResamples; resample_idx++) {
System.out.println(String.format("Resample: %s", resample_idx + 1));
// generate random sample of half size
Object[] randomSample = randomDataGenerator.nextSample(rqa_measures, sample_size);
sample.clear();
for (Object point : randomSample) sample.add((DoublePoint) point);
int bestK = 0;
double bestScore = Double.POSITIVE_INFINITY;
// cluster using different numbers of clusters
for (int k = 2; k < 17; k++) {
// seed the algorithm several times to have a better chance to escape local maxima
// this can also be done using
// org.apache.commons.math3.ml.clustering.MultiKMeansPlusPlusClusterer,
// but it doesn't return the actual scores, which is important in determining the number of
// clusters.
double bestInitScore = Double.POSITIVE_INFINITY;
for (int init_num = 0; init_num < numberOfInitializations; init_num++) {
KMeansPlusPlusClusterer<DoublePoint> clusterer =
new KMeansPlusPlusClusterer<DoublePoint>(
k, maxIterations, euclideanDistance, new ISAACRandom(init_num));
List<CentroidCluster<DoublePoint>> result = clusterer.cluster(sample);
final double score = evaluator.score(result);
bestInitScore = Math.min(bestInitScore, score);
} // for initializations
if (bestInitScore < bestScore) {
bestScore = bestInitScore;
bestK = k;
}
// for(CentroidCluster<DoublePoint> cc : result)
// System.out.println(Arrays.toString(cc.getCenter().getPoint()));
} // for number of clusters
System.out.println(String.format("Best k=%s, score=%s", bestK, bestScore));
} // for resampling
System.out.println(
String.format("Time for clustering: %s", System.currentTimeMillis() - before));
}
