Examples with Feature com.yahoo.search.predicate.index.Feature used on opensource projects

Example 1 with Feature

use of com.yahoo.search.predicate.index.Feature in project vespa by vespa-engine.

the class PredicateTreeAnalyzer method findMinFeature.

// Second analysis pass. Traverses tree in depth-first order. Determines the min-feature value.
private static double findMinFeature(Predicate predicate, boolean isNegated, AnalyzerContext context) {
    if (predicate instanceof Conjunction) {
        // Sum of children values.
        return ((Conjunction) predicate).getOperands().stream().mapToDouble(child -> findMinFeature(child, isNegated, context)).sum();
    } else if (predicate instanceof FeatureConjunction) {
        if (isNegated) {
            return 0.0;
        }
        // The FeatureConjunction is handled as a leaf node in the interval algorithm.
        IndexableFeatureConjunction ifc = new IndexableFeatureConjunction((FeatureConjunction) predicate);
        return 1.0 / context.conjunctionOccurrences.get(ifc.id);
    } else if (predicate instanceof Disjunction) {
        // Minimum value of children.
        return ((Disjunction) predicate).getOperands().stream().mapToDouble(child -> findMinFeature(child, isNegated, context)).min().getAsDouble();
    } else if (predicate instanceof Negation) {
        return findMinFeature(((Negation) predicate).getOperand(), !isNegated, context);
    } else if (predicate instanceof FeatureSet) {
        if (isNegated) {
            return 0.0;
        }
        double minFeature = 1.0;
        FeatureSet featureSet = (FeatureSet) predicate;
        for (String value : featureSet.getValues()) {
            long featureHash = Feature.createHash(featureSet.getKey(), value);
            // Clever mathematics to handle scenarios where same feature is used several places in predicate tree.
            minFeature = Math.min(minFeature, 1.0 / context.featureOccurrences.get(featureHash));
        }
        return minFeature;
    } else if (predicate instanceof FeatureRange) {
        if (isNegated) {
            return 0.0;
        }
        return 1.0 / context.featureOccurrences.get(PredicateHash.hash64(((FeatureRange) predicate).getKey()));
    } else {
        throw new UnsupportedOperationException("Cannot handle predicate of type " + predicate.getClass().getSimpleName());
    }
}