org.neo4j.gds.similarity.knn.metrics.LongPropertySimilarityComputer Maven / Gradle / Ivy

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/*
 * Copyright (c) "Neo4j"
 * Neo4j Sweden AB [http://neo4j.com]
 *
 * This file is part of Neo4j.
 *
 * Neo4j is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see .
 */
package org.neo4j.gds.similarity.knn.metrics;

import org.neo4j.gds.api.nodeproperties.ValueType;
import org.neo4j.gds.api.properties.nodes.NodePropertyValues;

final class LongPropertySimilarityComputer implements SimilarityComputer {
    private final NodePropertyValues nodePropertyValues;

    LongPropertySimilarityComputer(NodePropertyValues nodePropertyValues) {
        if (nodePropertyValues.valueType() != ValueType.LONG) {
            throw new IllegalArgumentException("The property is not of type LONG");
        }
        this.nodePropertyValues = nodePropertyValues;
    }

    @Override
    public double similarity(long firstNodeId, long secondNodeId) {
        var left = nodePropertyValues.longValue(firstNodeId);
        var right = nodePropertyValues.longValue(secondNodeId);
        var abs = Math.abs(left - right);
        if (abs == Long.MIN_VALUE) {
            abs = Long.MAX_VALUE;
        }
        return 1.0 / (1.0 + abs);
    }

    @Override
    public boolean isSymmetric() {
        return true;
    }
}