Examples with TransformStatistics org.tribuo.transform.TransformStatistics used on opensource projects

Example 1 with TransformStatistics

use of org.tribuo.transform.TransformStatistics in project tribuo by oracle.

the class Dataset method createTransformers.

/**
 * Takes a {@link TransformationMap} and converts it into a {@link TransformerMap} by
 * observing all the values in this dataset.
 * <p>
 * Does not mutate the dataset, if you wish to apply the TransformerMap, use
 * {@link MutableDataset#transform} or {@link TransformerMap#transformDataset}.
 * <p>
 * TransformerMaps operate on feature values which are present, sparse values
 * are ignored and not transformed. If the zeros should be transformed, call
 * {@link MutableDataset#densify} on the datasets before applying a transformer.
 * See {@link org.tribuo.transform} for a more detailed discussion of densify and includeImplicitZeroFeatures.
 * <p>
 * Throws {@link IllegalArgumentException} if the TransformationMap object has
 * regexes which apply to multiple features.
 * @param transformations The transformations to fit.
 * @param includeImplicitZeroFeatures Use the implicit zero feature values to construct the transformations.
 * @return A TransformerMap which can apply the transformations to a dataset.
 */
public TransformerMap createTransformers(TransformationMap transformations, boolean includeImplicitZeroFeatures) {
    ArrayList<String> featureNames = new ArrayList<>(getFeatureMap().keySet());
    // Validate map by checking no regex applies to multiple features.
    logger.fine(String.format("Processing %d feature specific transforms", transformations.getFeatureTransformations().size()));
    Map<String, List<Transformation>> featureTransformations = new HashMap<>();
    for (Map.Entry<String, List<Transformation>> entry : transformations.getFeatureTransformations().entrySet()) {
        // Compile the regex.
        Pattern pattern = Pattern.compile(entry.getKey());
        // Check all the feature names
        for (String name : featureNames) {
            // If the regex matches
            if (pattern.matcher(name).matches()) {
                List<Transformation> oldTransformations = featureTransformations.put(name, entry.getValue());
                // See if there is already a transformation list for that name.
                if (oldTransformations != null) {
                    throw new IllegalArgumentException("Feature name '" + name + "' matches multiple regexes, at least one of which was '" + entry.getKey() + "'.");
                }
            }
        }
    }
    // Populate the feature transforms map.
    Map<String, Queue<TransformStatistics>> featureStats = new HashMap<>();
    // sparseCount tracks how many times a feature was not observed
    Map<String, MutableLong> sparseCount = new HashMap<>();
    for (Map.Entry<String, List<Transformation>> entry : featureTransformations.entrySet()) {
        // Create the queue of feature transformations for this feature
        Queue<TransformStatistics> l = new LinkedList<>();
        for (Transformation t : entry.getValue()) {
            l.add(t.createStats());
        }
        // Add the queue to the map for that feature
        featureStats.put(entry.getKey(), l);
        sparseCount.put(entry.getKey(), new MutableLong(data.size()));
    }
    if (!transformations.getGlobalTransformations().isEmpty()) {
        // Append all the global transformations
        int ntransform = featureNames.size();
        logger.fine(String.format("Starting %,d global transformations", ntransform));
        int ndone = 0;
        for (String v : featureNames) {
            // Create the queue of feature transformations for this feature
            Queue<TransformStatistics> l = featureStats.computeIfAbsent(v, (k) -> new LinkedList<>());
            for (Transformation t : transformations.getGlobalTransformations()) {
                l.add(t.createStats());
            }
            // Add the queue to the map for that feature
            featureStats.put(v, l);
            // Generate the sparse count initialised to the number of features.
            sparseCount.putIfAbsent(v, new MutableLong(data.size()));
            ndone++;
            if (logger.isLoggable(Level.FINE) && ndone % 10000 == 0) {
                logger.fine(String.format("Completed %,d of %,d global transformations", ndone, ntransform));
            }
        }
    }
    Map<String, List<Transformer>> output = new LinkedHashMap<>();
    Set<String> removeSet = new LinkedHashSet<>();
    boolean initialisedSparseCounts = false;
    // Iterate through the dataset max(transformations.length) times.
    while (!featureStats.isEmpty()) {
        for (Example<T> example : data) {
            for (Feature f : example) {
                if (featureStats.containsKey(f.getName())) {
                    if (!initialisedSparseCounts) {
                        sparseCount.get(f.getName()).decrement();
                    }
                    List<Transformer> curTransformers = output.get(f.getName());
                    // Apply all current transformations
                    double fValue = TransformerMap.applyTransformerList(f.getValue(), curTransformers);
                    // Observe the transformed value
                    featureStats.get(f.getName()).peek().observeValue(fValue);
                }
            }
        }
        // Sparse counts are updated (this could be protected by an if statement)
        initialisedSparseCounts = true;
        removeSet.clear();
        // Emit the new transformers onto the end of the list in the output map.
        for (Map.Entry<String, Queue<TransformStatistics>> entry : featureStats.entrySet()) {
            TransformStatistics currentStats = entry.getValue().poll();
            if (includeImplicitZeroFeatures) {
                // Observe all the sparse feature values
                int unobservedFeatures = sparseCount.get(entry.getKey()).intValue();
                currentStats.observeSparse(unobservedFeatures);
            }
            // Get the transformer list for that feature (if absent)
            List<Transformer> l = output.computeIfAbsent(entry.getKey(), (k) -> new ArrayList<>());
            // Generate the transformer and add it to the appropriate list.
            l.add(currentStats.generateTransformer());
            // If the queue is empty, remove that feature, ensuring that featureStats is eventually empty.
            if (entry.getValue().isEmpty()) {
                removeSet.add(entry.getKey());
            }
        }
        // Remove the features with empty queues.
        for (String s : removeSet) {
            featureStats.remove(s);
        }
    }
    return new TransformerMap(output, getProvenance(), transformations.getProvenance());
}