/**
* Causes all known instances of {@link RandomGenerator}, and future ones, to be started from a
* fixed seed. This is useful for making tests deterministic.
*/
public static void useTestSeed() {
useTestSeed = true;
synchronized (INSTANCES) {
for (RandomGenerator random : INSTANCES.keySet()) {
random.setSeed(TEST_SEED);
}
INSTANCES.clear();
}
}
public GaussianDistribution(final int dims, final double[] pos, final double size) {
final Random random = Util.R.get();
this.dims = dims;
final double[] means = new double[dims];
for (int i = 0; i < means.length; i++) {
means[i] = 1;
}
final double[][] diaganals = new double[dims][];
for (int i = 0; i < diaganals.length; i++) {
diaganals[i] = new double[dims];
diaganals[i][i] = 1;
}
final RandomGenerator rng = new JDKRandomGenerator();
rng.setSeed(random.nextInt());
this.pos = pos;
this.size = size;
}
/** Test points that are very close together. See issue MATH-546. */
@Test
public void testSmallDistances() {
// Create a bunch of CloseDoublePoints. Most are identical, but one is different by a
// small distance.
int[] repeatedArray = {0};
int[] uniqueArray = {1};
DoublePoint repeatedPoint = new DoublePoint(repeatedArray);
DoublePoint uniquePoint = new DoublePoint(uniqueArray);
Collection<DoublePoint> points = new ArrayList<DoublePoint>();
final int NUM_REPEATED_POINTS = 10 * 1000;
for (int i = 0; i < NUM_REPEATED_POINTS; ++i) {
points.add(repeatedPoint);
}
points.add(uniquePoint);
// Ask a KMeansPlusPlusClusterer to run zero iterations (i.e., to simply choose initial
// cluster centers).
final long RANDOM_SEED = 0;
final int NUM_CLUSTERS = 2;
final int NUM_ITERATIONS = 0;
random.setSeed(RANDOM_SEED);
KMeansPlusPlusClusterer<DoublePoint> clusterer =
new KMeansPlusPlusClusterer<DoublePoint>(
NUM_CLUSTERS, NUM_ITERATIONS, new CloseDistance(), random);
List<CentroidCluster<DoublePoint>> clusters = clusterer.cluster(points);
// Check that one of the chosen centers is the unique point.
boolean uniquePointIsCenter = false;
for (CentroidCluster<DoublePoint> cluster : clusters) {
if (cluster.getCenter().equals(uniquePoint)) {
uniquePointIsCenter = true;
}
}
Assert.assertTrue(uniquePointIsCenter);
}
@Before
public void setUp() {
random = new JDKRandomGenerator();
random.setSeed(1746432956321l);
}