001/*
002 * Copyright (c) 2015-2020, Oracle and/or its affiliates. All rights reserved.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *     http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.tribuo.math.util;
018
019import org.tribuo.math.la.DenseSparseMatrix;
020import org.tribuo.math.la.SparseVector;
021
022import java.io.Serializable;
023
024/**
025 * An interface for merging an array of {@link DenseSparseMatrix} into a single {@link DenseSparseMatrix}.
026 * <p>
027 * Mergers are principally used to aggregate gradients across a minibatch.
028 * <p>
029 * Merging is done by summation.
030 */
031public interface Merger extends Serializable {
032
033    /**
034     * Merges an array of DenseSparseMatrix into a single DenseSparseMatrix.
035     * @param inputs The matrices to merge.
036     * @return The merged matrix.
037     */
038    public DenseSparseMatrix merge(DenseSparseMatrix[] inputs);
039
040    /**
041     * Merges an array of SparseVector into a single SparseVector.
042     * @param inputs The vectors to merge.
043     * @return The merged vector.
044     */
045    public SparseVector merge(SparseVector[] inputs);
046
047}