/**
* Strips the dataset down to the specified labels and remaps them
*
* @param labels the labels to strip down to
*/
public void filterAndStrip(int[] labels) {
FloatDataSet filtered = filterBy(labels);
List<Integer> newLabels = new ArrayList<>();
// map new labels to index according to passed in labels
Map<Integer, Integer> labelMap = new HashMap<>();
for (int i = 0; i < labels.length; i++) labelMap.put(labels[i], i);
// map examples
for (int i = 0; i < filtered.numExamples(); i++) {
int o2 = filtered.get(i).outcome();
int outcome = labelMap.get(o2);
newLabels.add(outcome);
}
FloatMatrix newLabelMatrix = new FloatMatrix(filtered.numExamples(), labels.length);
if (newLabelMatrix.rows != newLabels.size())
throw new IllegalStateException("Inconsistent label sizes");
for (int i = 0; i < newLabelMatrix.rows; i++) {
Integer i2 = newLabels.get(i);
if (i2 == null) throw new IllegalStateException("Label not found on row " + i);
FloatMatrix newRow = MatrixUtil.toOutcomeVectorFloat(i2, labels.length);
newLabelMatrix.putRow(i, newRow);
}
setFirst(filtered.getFirst());
setSecond(newLabelMatrix);
}
public static FloatDataSet merge(List<FloatDataSet> data) {
if (data.isEmpty()) throw new IllegalArgumentException("Unable to merge empty dataset");
FloatDataSet first = data.get(0);
int numExamples = totalExamples(data);
FloatMatrix in = new FloatMatrix(numExamples, first.getFirst().columns);
FloatMatrix out = new FloatMatrix(numExamples, first.getSecond().columns);
int count = 0;
for (int i = 0; i < data.size(); i++) {
FloatDataSet d1 = data.get(i);
for (int j = 0; j < d1.numExamples(); j++) {
FloatDataSet example = d1.get(j);
in.putRow(count, example.getFirst());
out.putRow(count, example.getSecond());
count++;
}
}
return new FloatDataSet(in, out);
}