/*

  * 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 org.apache.giraph.aggregators.matrix.sparse;

 import org.apache.giraph.aggregators.AggregatorUsage;

 import org.apache.giraph.aggregators.matrix.MatrixSumAggregator;

 import org.apache.giraph.master.MasterAggregatorUsage;

 import org.apache.giraph.worker.WorkerAggregatorUsage;

 /**

  * The long matrix aggregator is used to register and aggregate long matrices.

  */

 public class LongSparseMatrixSumAggregator extends MatrixSumAggregator {

   /** sparse vector with single entry */

   private LongSparseVector singletonVector = new LongSparseVector();

   /**

    * Create a new matrix aggregator with the given prefix name for the vector

    * aggregators.

    *

    * @param name the prefix for the row vector aggregators

    */

   public LongSparseMatrixSumAggregator(String name) {

     super(name);

   }

   /**

    * Register the long vector aggregators, one for each row of the matrix.

    *

    * @param numRows the number of rows

    * @param master the master to register the aggregators

    */

   public void register(int numRows, MasterAggregatorUsage master)

     throws InstantiationException, IllegalAccessException {

     for (int i = 0; i < numRows; ++i) {

       master.registerAggregator(getRowAggregatorName(i),

           LongSparseVectorSumAggregator.class);

     }

   }

   /**

    * Add the given value to the entry specified.

    *

    * @param i the row

    * @param j the column

    * @param v the value

    * @param worker the worker to aggregate

    */

   public void aggregate(int i, int j, long v, WorkerAggregatorUsage worker) {

     singletonVector.clear();

     singletonVector.set(j, v);

     worker.aggregate(getRowAggregatorName(i), singletonVector);

   }

   /**

    * Set the values of the matrix to the master specified. This is typically

    * used in the master, to build an external LongMatrix and only set it at

    * the end.

    *

    * @param matrix the matrix to set the values

    * @param master the master

    */

   public void setMatrix(LongSparseMatrix matrix,

       MasterAggregatorUsage master) {

     int numRows = matrix.getNumRows();

     for (int i = 0; i < numRows; ++i) {

       master.setAggregatedValue(getRowAggregatorName(i), matrix.getRow(i));

     }

   }

   /**

    * Read the aggregated values of the matrix.

    *

    * @param numRows the number of rows

    * @param aggUser the master or worker

    * @return the long matrix

    */

   public LongSparseMatrix getMatrix(int numRows, AggregatorUsage aggUser) {

     LongSparseMatrix matrix = new LongSparseMatrix(numRows);

     for (int i = 0; i < numRows; ++i) {

       LongSparseVector vec = aggUser.getAggregatedValue(

           getRowAggregatorName(i));

       matrix.setRow(i, vec);

     }

     return matrix;

   }

 }