Examples with DBIDPair de.lmu.ifi.dbs.elki.database.ids.DBIDPair used on opensource projects

Example 1 with DBIDPair

use of de.lmu.ifi.dbs.elki.database.ids.DBIDPair in project elki by elki-project.

the class PartitionApproximationMaterializeKNNPreprocessor method preprocess.

@Override
protected void preprocess() {
    DistanceQuery<O> distanceQuery = relation.getDistanceQuery(distanceFunction);
    storage = DataStoreUtil.makeStorage(relation.getDBIDs(), DataStoreFactory.HINT_STATIC, KNNList.class);
    MeanVariance ksize = new MeanVariance();
    if (LOG.isVerbose()) {
        LOG.verbose("Approximating nearest neighbor lists to database objects");
    }
    // Produce a random shuffling of the IDs:
    ArrayDBIDs[] parts = DBIDUtil.randomSplit(relation.getDBIDs(), partitions, rnd);
    FiniteProgress progress = LOG.isVerbose() ? new FiniteProgress("Processing partitions", partitions, LOG) : null;
    for (int part = 0; part < partitions; part++) {
        final ArrayDBIDs ids = parts[part];
        final int size = ids.size();
        Object2DoubleOpenHashMap<DBIDPair> cache = new Object2DoubleOpenHashMap<>((size * size * 3) >> 3);
        cache.defaultReturnValue(Double.NaN);
        for (DBIDIter iter = ids.iter(); iter.valid(); iter.advance()) {
            KNNHeap kNN = DBIDUtil.newHeap(k);
            for (DBIDIter iter2 = ids.iter(); iter2.valid(); iter2.advance()) {
                DBIDPair key = DBIDUtil.newPair(iter, iter2);
                double d = cache.removeDouble(key);
                if (d == d) {
                    // Not NaN
                    // consume the previous result.
                    kNN.insert(d, iter2);
                } else {
                    // compute new and store the previous result.
                    d = distanceQuery.distance(iter, iter2);
                    kNN.insert(d, iter2);
                    // put it into the cache, but with the keys reversed
                    key = DBIDUtil.newPair(iter2, iter);
                    cache.put(key, d);
                }
            }
            ksize.put(kNN.size());
            storage.put(iter, kNN.toKNNList());
        }
        if (LOG.isDebugging() && cache.size() > 0) {
            LOG.warning("Cache should be empty after each run, but still has " + cache.size() + " elements.");
        }
        LOG.incrementProcessed(progress);
    }
    LOG.ensureCompleted(progress);
    if (LOG.isVerbose()) {
        LOG.verbose("On average, " + ksize.getMean() + " +- " + ksize.getSampleStddev() + " neighbors returned.");
    }
}

Example 2 with DBIDPair

use of de.lmu.ifi.dbs.elki.database.ids.DBIDPair in project elki by elki-project.

the class MetricalIndexApproximationMaterializeKNNPreprocessor method preprocess.

@Override
protected void preprocess() {
    final Logging log = getLogger();
    DistanceQuery<O> distanceQuery = relation.getDistanceQuery(distanceFunction);
    MetricalIndexTree<O, N, E> index = getMetricalIndex(relation);
    createStorage();
    MeanVariance pagesize = new MeanVariance();
    MeanVariance ksize = new MeanVariance();
    if (log.isVerbose()) {
        log.verbose("Approximating nearest neighbor lists to database objects");
    }
    List<E> leaves = index.getLeaves();
    FiniteProgress progress = getLogger().isVerbose() ? new FiniteProgress("Processing leaf nodes", leaves.size(), getLogger()) : null;
    for (E leaf : leaves) {
        N node = index.getNode(leaf);
        int size = node.getNumEntries();
        pagesize.put(size);
        if (log.isDebuggingFinest()) {
            log.debugFinest("NumEntires = " + size);
        }
        // Collect the ids in this node.
        ArrayModifiableDBIDs ids = DBIDUtil.newArray(size);
        for (int i = 0; i < size; i++) {
            ids.add(((LeafEntry) node.getEntry(i)).getDBID());
        }
        Object2DoubleOpenHashMap<DBIDPair> cache = new Object2DoubleOpenHashMap<>((size * size * 3) >> 2);
        cache.defaultReturnValue(Double.NaN);
        for (DBIDIter id = ids.iter(); id.valid(); id.advance()) {
            KNNHeap kNN = DBIDUtil.newHeap(k);
            for (DBIDIter id2 = ids.iter(); id2.valid(); id2.advance()) {
                DBIDPair key = DBIDUtil.newPair(id, id2);
                double d = cache.removeDouble(key);
                if (d == d) {
                    // Not NaN
                    // consume the previous result.
                    kNN.insert(d, id2);
                } else {
                    // compute new and store the previous result.
                    d = distanceQuery.distance(id, id2);
                    kNN.insert(d, id2);
                    // put it into the cache, but with the keys reversed
                    key = DBIDUtil.newPair(id2, id);
                    cache.put(key, d);
                }
            }
            ksize.put(kNN.size());
            storage.put(id, kNN.toKNNList());
        }
        if (log.isDebugging() && cache.size() > 0) {
            log.warning("Cache should be empty after each run, but still has " + cache.size() + " elements.");
        }
        log.incrementProcessed(progress);
    }
    log.ensureCompleted(progress);
    if (log.isVerbose()) {
        log.verbose("Average page size = " + pagesize.getMean() + " +- " + pagesize.getSampleStddev());
        log.verbose("On average, " + ksize.getMean() + " +- " + ksize.getSampleStddev() + " neighbors returned.");
    }
}