/**
* Removes the point with the given index.
*
* @param index the index to remove
*/
public void removePoint(int index) {
distanceMatrix.remove(index);
for (List<Pair<Integer, Double>> distances : distanceMatrix) {
ListIterator<Pair<Integer, Double>> iterator = distances.listIterator();
while (iterator.hasNext()) {
Pair<Integer, Double> point = iterator.next();
if (point.getFirst() == index) {
iterator.remove();
} else if (point.getFirst() > index) {
// decrement the index so it stays aligned with the
// index in distanceMatrix
iterator.set(new Pair<Integer, Double>(point.getFirst() - 1, point.getSecond()));
}
}
}
}
private Collection<List<TimeSample>> collectUserTimeSamples(Pair<User, User> pair) {
Collection<List<TimeSample>> datasets = new ArrayList<>();
// for (User user : users) {
UserData userData = this.usersData.get(pair.getFirst());
datasets.add(new ArrayList<>(userData.getBtData()));
datasets.add(new ArrayList<>(userData.getActivityData()));
datasets.add(new ArrayList<>(userData.getWifiData()));
datasets.add(new ArrayList<>(userData.getAudioData()));
userData = this.usersData.get(pair.getSecond());
datasets.add(new ArrayList<>(userData.getBtData()));
datasets.add(new ArrayList<>(userData.getActivityData()));
datasets.add(new ArrayList<>(userData.getWifiData()));
datasets.add(new ArrayList<>(userData.getAudioData()));
// }
return datasets;
}
/**
* Computes the Kendall's Tau rank correlation coefficient between the two arrays.
*
* @param xArray first data array
* @param yArray second data array
* @return Returns Kendall's Tau rank correlation coefficient for the two arrays
* @throws DimensionMismatchException if the arrays lengths do not match
*/
public double correlation(final double[] xArray, final double[] yArray)
throws DimensionMismatchException {
if (xArray.length != yArray.length) {
throw new DimensionMismatchException(xArray.length, yArray.length);
}
final int n = xArray.length;
final long numPairs = n * (n - 1l) / 2l;
@SuppressWarnings("unchecked")
Pair<Double, Double>[] pairs = new Pair[n];
for (int i = 0; i < n; i++) {
pairs[i] = new Pair<Double, Double>(xArray[i], yArray[i]);
}
Arrays.sort(
pairs,
new Comparator<Pair<Double, Double>>() {
public int compare(Pair<Double, Double> pair1, Pair<Double, Double> pair2) {
int compareFirst = pair1.getFirst().compareTo(pair2.getFirst());
return compareFirst != 0
? compareFirst
: pair1.getSecond().compareTo(pair2.getSecond());
}
});
int tiedXPairs = 0;
int tiedXYPairs = 0;
int consecutiveXTies = 1;
int consecutiveXYTies = 1;
Pair<Double, Double> prev = pairs[0];
for (int i = 1; i < n; i++) {
final Pair<Double, Double> curr = pairs[i];
if (curr.getFirst().equals(prev.getFirst())) {
consecutiveXTies++;
if (curr.getSecond().equals(prev.getSecond())) {
consecutiveXYTies++;
} else {
tiedXYPairs += consecutiveXYTies * (consecutiveXYTies - 1) / 2;
consecutiveXYTies = 1;
}
} else {
tiedXPairs += consecutiveXTies * (consecutiveXTies - 1) / 2;
consecutiveXTies = 1;
tiedXYPairs += consecutiveXYTies * (consecutiveXYTies - 1) / 2;
consecutiveXYTies = 1;
}
prev = curr;
}
tiedXPairs += consecutiveXTies * (consecutiveXTies - 1) / 2;
tiedXYPairs += consecutiveXYTies * (consecutiveXYTies - 1) / 2;
int swaps = 0;
@SuppressWarnings("unchecked")
Pair<Double, Double>[] pairsDestination = new Pair[n];
for (int segmentSize = 1; segmentSize < n; segmentSize <<= 1) {
for (int offset = 0; offset < n; offset += 2 * segmentSize) {
int i = offset;
final int iEnd = FastMath.min(i + segmentSize, n);
int j = iEnd;
final int jEnd = FastMath.min(j + segmentSize, n);
int copyLocation = offset;
while (i < iEnd || j < jEnd) {
if (i < iEnd) {
if (j < jEnd) {
if (pairs[i].getSecond().compareTo(pairs[j].getSecond()) <= 0) {
pairsDestination[copyLocation] = pairs[i];
i++;
} else {
pairsDestination[copyLocation] = pairs[j];
j++;
swaps += iEnd - i;
}
} else {
pairsDestination[copyLocation] = pairs[i];
i++;
}
} else {
pairsDestination[copyLocation] = pairs[j];
j++;
}
copyLocation++;
}
}
final Pair<Double, Double>[] pairsTemp = pairs;
pairs = pairsDestination;
pairsDestination = pairsTemp;
}
int tiedYPairs = 0;
int consecutiveYTies = 1;
prev = pairs[0];
for (int i = 1; i < n; i++) {
final Pair<Double, Double> curr = pairs[i];
if (curr.getSecond().equals(prev.getSecond())) {
consecutiveYTies++;
} else {
tiedYPairs += consecutiveYTies * (consecutiveYTies - 1) / 2;
consecutiveYTies = 1;
}
prev = curr;
}
tiedYPairs += consecutiveYTies * (consecutiveYTies - 1) / 2;
int concordantMinusDiscordant = numPairs - tiedXPairs - tiedYPairs + tiedXYPairs - 2 * swaps;
return concordantMinusDiscordant
/ FastMath.sqrt((numPairs - tiedXPairs) * (numPairs - tiedYPairs));
}
private void loadFeaturesData(Pair<User, User> pair) {
usersData.put(pair.getFirst(), new UserFeaturesDataLoader(pair.getFirst(), interval).get());
usersData.put(pair.getSecond(), new UserFeaturesDataLoader(pair.getSecond(), interval).get());
}