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1   //******************************************************************************
2   //
3   // File:    ObjectMatrixReductionBuf.java
4   // Package: edu.rit.mp.buf
5   // Unit:    Class edu.rit.mp.buf.ObjectMatrixReductionBuf
6   //
7   // This Java source file is copyright (C) 2009 by Alan Kaminsky. All rights
8   // reserved. For further information, contact the author, Alan Kaminsky, at
9   // ark@cs.rit.edu.
10  //
11  // This Java source file is part of the Parallel Java Library ("PJ"). PJ is free
12  // software; you can redistribute it and/or modify it under the terms of the GNU
13  // General Public License as published by the Free Software Foundation; either
14  // version 3 of the License, or (at your option) any later version.
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18  // A PARTICULAR PURPOSE. See the GNU General Public License for more details.
19  //
20  // Linking this library statically or dynamically with other modules is making a
21  // combined work based on this library. Thus, the terms and conditions of the GNU
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25  // permission to link this library with independent modules to produce an
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35  // A copy of the GNU General Public License is provided in the file gpl.txt. You
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39  //******************************************************************************
40  package edu.rit.mp.buf;
41  
42  import edu.rit.mp.Buf;
43  import edu.rit.mp.ObjectBuf;
44  import edu.rit.pj.reduction.ObjectOp;
45  import edu.rit.pj.reduction.Op;
46  import edu.rit.pj.reduction.ReduceArrays;
47  import edu.rit.util.Range;
48  
49  /**
50   * Class ObjectMatrixReductionBuf provides a reduction buffer for class
51   * {@linkplain ObjectMatrixBuf}.
52   *
53   * @param <T> Data type of the objects in the buffer.
54   *
55   * @author Alan Kaminsky
56   * @version 05-Apr-2009
57   */
58  @SuppressWarnings("unchecked")
59  class ObjectMatrixReductionBuf<T>
60          extends ObjectMatrixBuf<T> {
61  
62  // Hidden data members.
63      ObjectOp<T> myOp;
64      ObjectMatrixBuf<T> myBuf;
65  
66  // Exported constructors.
67      /**
68       * Construct a new object matrix reduction buffer. It is assumed that the
69       * rows and columns of <code>theMatrix</code> are allocated and that each row of
70       * <code>theMatrix</code> has the same number of columns.
71       *
72       * @param theMatrix Matrix.
73       * @param theRowRange Range of rows to include.
74       * @param theColRange Range of columns to include.
75       * @param op Binary operation.
76       * @param theBuf Underlying object matrix buffer.
77       * @exception NullPointerException (unchecked exception) Thrown if
78       * <code>op</code> is null.
79       */
80      public ObjectMatrixReductionBuf(T[][] theMatrix,
81              Range theRowRange,
82              Range theColRange,
83              ObjectOp<T> op,
84              ObjectMatrixBuf<T> theBuf) {
85          super(theMatrix, theRowRange, theColRange);
86          if (op == null) {
87              throw new NullPointerException("ObjectMatrixReductionBuf(): op is null");
88          }
89          myOp = op;
90          myBuf = theBuf;
91      }
92  
93  // Exported operations.
94      /**
95       * Store the given item in this buffer.
96       * <P>
97       * The <code>put()</code> method must not block the calling thread; if it does,
98       * all message I/O in MP will be blocked.
99       *
100      * @param i Item index in the range 0 .. <code>length()</code>-1.
101      * @param item Item to be stored at index <code>i</code>.
102      */
103     public void put(int i, T item) {
104         int row = i2r(i) * myRowStride + myLowerRow;
105         int col = i2c(i) * myColStride + myLowerCol;
106         myMatrix[row][col] = myOp.op(myMatrix[row][col], item);
107         reset();
108         myBuf.reset();
109     }
110 
111     /**
112      * {@inheritDoc}
113      *
114      * Copy items from the given buffer to this buffer. The number of items
115      * copied is this buffer's length or <code>theSrc</code>'s length, whichever is
116      * smaller. If <code>theSrc</code> is this buffer, the <code>copy()</code> method
117      * does nothing.
118      * @exception ClassCastException (unchecked exception) Thrown if
119      * <code>theSrc</code>'s item data type is not the same as this buffer's item
120      * data type.
121      */
122     public void copy(Buf theSrc) {
123         if (theSrc == this) {
124         } else if (theSrc instanceof ObjectMatrixBuf) {
125             ObjectMatrixBuf<T> src = (ObjectMatrixBuf<T>) theSrc;
126             ReduceArrays.reduce(src.myMatrix, src.myRowRange, src.myColRange,
127                     this.myMatrix, this.myRowRange, this.myColRange,
128                     myOp);
129             reset();
130             myBuf.reset();
131         } else {
132             ObjectBuf.defaultCopy((ObjectBuf<T>) theSrc, this);
133             reset();
134             myBuf.reset();
135         }
136     }
137 
138     /**
139      * {@inheritDoc}
140      *
141      * Create a buffer for performing parallel reduction using the given binary
142      * operation. The results of the reduction are placed into this buffer.
143      * @exception ClassCastException (unchecked exception) Thrown if this
144      * buffer's element data type and the given binary operation's argument data
145      * type are not the same.
146      */
147     public Buf getReductionBuf(Op op) {
148         throw new UnsupportedOperationException();
149     }
150 
151 }