// initialize the data structures
public void Initialize() {
Logging.println("NTrain=" + NTrain + ", NTest=" + NTest + ", M_i=" + M, LogLevel.DEBUGGING_LOG);
Logging.println("K=" + K + ", L=" + L, LogLevel.DEBUGGING_LOG);
Logging.println("eta=" + eta + ", maxIter=" + maxIter, LogLevel.DEBUGGING_LOG);
Logging.println(
"lambdaD=" + lambdaD + ", lambdaF=" + lambdaP + ", lamdaW=" + lambdaW + ", beta=" + beta,
LogLevel.DEBUGGING_LOG);
// avoid zero/negative sliding window increments,
// or increments greater than the window size
if (deltaT < 1) deltaT = 1;
else if (deltaT > L) deltaT = L;
NSegments = (M - L) / deltaT;
Logging.println("deltaT=" + deltaT + ", NSegments=" + NSegments, LogLevel.DEBUGGING_LOG);
cR = beta / (NSegments * L);
cA = (1 - beta);
SegmentTimeSeriesDataset();
InitializePatternsProbabilityDistance();
InitializeHardMembershipsToClosestPattern();
// set the labels to be binary 0 and 1, needed for the logistic loss
for (int i = 0; i < NTrain + NTest; i++) if (Y.get(i) != 1.0) Y.set(i, 0, 0.0);
InitializeWeights();
Logging.println("Initializations Completed!", LogLevel.DEBUGGING_LOG);
}
// compute the MCR on the test set
private double GetMCRTestSet() {
int numErrors = 0;
for (int i = NTrain; i < NTrain + NTest; i++) {
double label_i = Sigmoid.Calculate(Predict(i));
if ((Y.get(i) == 1 && label_i < 0.5) || (Y.get(i) == 0 && label_i >= 0.5)) numErrors++;
}
return (double) numErrors / (double) NTest;
}
// the the MSE of the H loss
public double GetLossH() {
double numInstances = 0;
double errorSum = 0;
for (int i = 0; i < numTotalInstances; i++)
for (int l = 0; l < numPatterns; l++) {
if (H.get(i, l) != GlobalValues.MISSING_VALUE) {
double err = H.get(i, l) - MatrixUtilities.getRowByColumnProduct(S, i, P, l);
errorSum += err * err;
numInstances += 1.0;
}
}
return errorSum / numInstances;
}
// get the log loss of the target prediction
public double GetErrorRate(int startIndex, int endIndex) {
int numIncorrectClassifications = 0;
int numInstances = 0;
for (int i = startIndex; i < endIndex; i++) {
if (Y.get(i) != GlobalValues.MISSING_VALUE) {
double y = Y.get(i);
double y_predicted = PredictLabel(i);
if (y != y_predicted) numIncorrectClassifications++;
numInstances++;
}
}
return (double) numIncorrectClassifications / (double) numInstances;
}
// get the log loss of the target prediction
public double GetLossY(int startIndex, int endIndex) {
double YTrainLoss = 0;
int numObservedCells = 0;
for (int i = startIndex; i < endIndex; i++)
for (int l = 0; l < numLabels; l++)
if (YExtended.get(i, l) != GlobalValues.MISSING_VALUE) {
double y_hat_i =
Sigmoid.Calculate(
MatrixUtilities.getRowByColumnProduct(S, i, W, l)); // + biasW[l]);
double y_i = YExtended.get(i, l);
YTrainLoss += -y_i * Math.log(y_hat_i) - (1 - y_i) * Math.log(1 - y_hat_i);
numObservedCells++;
}
return YTrainLoss / (double) numObservedCells;
}
// compute the histogram matrix
public void ComputeHistogram() {
BagOfPatterns bop = new BagOfPatterns();
bop.representationType = RepresentationType.Polynomial;
bop.slidingWindowSize = slidingWindowSize;
bop.representationType = RepresentationType.Polynomial;
bop.innerDimension = innerDimension;
bop.alphabetSize = alphabetSize;
bop.polyDegree = degree;
H = bop.CreateWordFrequenciesMatrix(X);
numPatterns = H.getDimColumns();
for (int i = 0; i < H.getDimRows(); i++)
for (int j = 0; j < H.getDimColumns(); j++)
if (H.get(i, j) == 0) {
// H.set(i, j, GlobalValues.MISSING_VALUE);
}
Logging.println("Histogram Sparsity: " + H.GetSparsityRatio(), LogLevel.DEBUGGING_LOG);
}
// partition the time series into segments
public void SegmentTimeSeriesDataset() {
S = new double[NTrain + NTest][NSegments][L];
for (int i = 0; i < NTrain + NTest; i++) {
for (int j = 0; j < NSegments; j++) {
for (int l = 0; l < L; l++) S[i][j][l] = T.get(i, (j * deltaT) + l);
// normalize the segment
double[] normalizedSegment = StatisticalUtilities.Normalize(S[i][j]);
for (int l = 0; l < L; l++) S[i][j][l] = normalizedSegment[l];
}
}
Logging.println("Partion to Normalized Segments Completed!", LogLevel.DEBUGGING_LOG);
}
public void LearnLA(boolean updateOnlyW) {
if (beta == 1) return;
double e_i = 0, F_ik = 0;
double regWConst = (2 * lambdaW) / NTrain;
for (int i = 0; i < NTrain; i++) {
e_i = Y.get(i) - Sigmoid.Calculate(Predict(i));
for (int k = 0; k < K; k++) {
F_ik = 0;
for (int j = 0; j < NSegments; j++) {
D[i][j][k] -= eta * ((1 - beta) * -2 * e_i * W[k] + lambdaD * D[i][j][k]);
F_ik += D[i][j][k];
}
W[k] -= eta * ((1 - beta) * -2 * e_i * F_ik + regWConst * W[k]);
}
}
}
// initialize the matrices
public void Initialize() {
// compute the histogram matrix
ComputeHistogram();
// create the extended Y
YExtended = new Matrix(numTotalInstances, numLabels);
// set all the cells to zero initially
for (int i = 0; i < numTrainInstances; i++)
for (int l = 0; l < numLabels; l++) YExtended.set(i, l, 0.0);
// set to 1 only the column corresponding to the label
for (int i = 0; i < numTotalInstances; i++) YExtended.set(i, (int) Y.get(i), 1.0);
// randomly initialize the latent matrices
S = new Matrix(numTotalInstances, D);
S.RandomlyInitializeCells(0, 1);
P = new Matrix(D, numPatterns);
P.RandomlyInitializeCells(0, 1);
biasP = new double[numPatterns];
for (int l = 0; l < numPatterns; l++) biasP[l] = H.GetColumnMean(l);
W = new Matrix(D, numLabels);
W.RandomlyInitializeCells(0, 1);
biasW = new double[numLabels];
for (int l = 0; l < numLabels; l++) biasW[l] = YExtended.GetColumnMean(l);
// record the observed histogram values
HObserved = new ArrayList<Tripple>();
for (int i = 0; i < H.getDimRows(); i++)
for (int j = 0; j < H.getDimColumns(); j++)
if (H.get(i, j) != GlobalValues.MISSING_VALUE) HObserved.add(new Tripple(i, j));
Collections.shuffle(HObserved);
// record the observed label values
YObserved = new ArrayList<Tripple>();
for (int i = 0; i < numTrainInstances; i++)
for (int l = 0; l < YExtended.getDimColumns(); l++)
if (YExtended.get(i, l) != GlobalValues.MISSING_VALUE) YObserved.add(new Tripple(i, l));
Collections.shuffle(YObserved);
}
// compute the accuracy loss of instance i according to the
// smooth hinge loss
public double AccuracyLoss(int i) {
double Y_hat_i = Predict(i);
double sig_y_i = Sigmoid.Calculate(Y_hat_i);
return -Y.get(i) * Math.log(sig_y_i) - (1 - Y.get(i)) * Math.log(1 - sig_y_i);
}
