datafu.pig.hash.lsh.LSHFamily.java Source code

Introduction

Here is the source code for datafu.pig.hash.lsh.LSHFamily.java

Source

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package datafu.pig.hash.lsh;

import java.util.List;

import org.apache.commons.math.linear.RealVector;

import com.google.common.base.Function;
import com.google.common.collect.Iterables;

import datafu.pig.hash.lsh.interfaces.LSH;

/**
 * A family of k locality sensitive hashes.  For a given point, k hashes will be computed.
 * @author cstella
 *
 */
public class LSHFamily {

    private List<LSH> hashes;

    /**
     * Construct a family of hashes
     * @param hashes Hashes which will be applied in turn to a given point
     */
    public LSHFamily(List<LSH> hashes) {
        this.hashes = hashes;
    }

    /**
     * Compute the family of k-hashes for a vector.
     * 
     * @param vector
     * @return An iterable of hashes
     */
    public Iterable<Long> apply(final RealVector vector) {
        return Iterables.transform(hashes, new Function<LSH, Long>() {
            @Override
            public Long apply(LSH lsh) {
                return lsh.apply(vector);
            }
        });
    }

}