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1   //******************************************************************************
2   //
3   // File:    Unsigned16BitIntegerMatrixReductionBuf_1.java
4   // Package: edu.rit.mp.buf
5   // Unit:    Class edu.rit.mp.buf.Unsigned16BitIntegerMatrixReductionBuf_1
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
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17  // WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
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19  //
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21  // combined work based on this library. Thus, the terms and conditions of the GNU
22  // General Public License cover the whole combination.
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39  //******************************************************************************
40  package edu.rit.mp.buf;
41  
42  import java.nio.ByteBuffer;
43  import java.nio.ShortBuffer;
44  
45  import edu.rit.mp.Buf;
46  import edu.rit.mp.Unsigned16BitIntegerBuf;
47  import edu.rit.pj.reduction.IntegerOp;
48  import edu.rit.pj.reduction.Op;
49  import edu.rit.pj.reduction.ReduceArrays;
50  import edu.rit.util.Range;
51  
52  /**
53   * Class Unsigned16BitIntegerMatrixReductionBuf_1 provides a reduction buffer
54   * for class {@linkplain Unsigned16BitIntegerMatrixBuf_1}.
55   *
56   * @author Alan Kaminsky
57   * @version 05-Apr-2009
58   */
59  class Unsigned16BitIntegerMatrixReductionBuf_1
60          extends Unsigned16BitIntegerMatrixBuf_1 {
61  
62  // Hidden data members.
63      IntegerOp myOp;
64  
65  // Exported constructors.
66      /**
67       * Construct a new unsigned 16-bit integer matrix reduction buffer. It is
68       * assumed that the rows and columns of <code>theMatrix</code> are allocated and
69       * that each row of <code>theMatrix</code> has the same number of columns.
70       *
71       * @param theMatrix Matrix.
72       * @param theRowRange Range of rows to include. The stride is assumed to be
73       * 1.
74       * @param theColRange Range of columns to include. The stride is assumed to
75       * be 1.
76       * @param op Binary operation.
77       * @exception NullPointerException (unchecked exception) Thrown if
78       * <code>op</code> is null.
79       */
80      public Unsigned16BitIntegerMatrixReductionBuf_1(int[][] theMatrix,
81              Range theRowRange,
82              Range theColRange,
83              IntegerOp op) {
84          super(theMatrix, theRowRange, theColRange);
85          if (op == null) {
86              throw new NullPointerException("Unsigned16BitIntegerMatrixReductionBuf_1(): op is null");
87          }
88          myOp = op;
89      }
90  
91  // Exported operations.
92      /**
93       * {@inheritDoc}
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     public void put(int i,
101             int item) {
102         int row = (i / myColCount) + myLowerRow;
103         int col = (i % myColCount) + myLowerCol;
104         myMatrix[row][col] = myOp.op(myMatrix[row][col], item);
105     }
106 
107     /**
108      * {@inheritDoc}
109      *
110      * Copy items from the given buffer to this buffer. The number of items
111      * copied is this buffer's length or <code>theSrc</code>'s length, whichever is
112      * smaller. If <code>theSrc</code> is this buffer, the <code>copy()</code> method
113      * does nothing.
114      * @exception ClassCastException (unchecked exception) Thrown if
115      * <code>theSrc</code>'s item data type is not the same as this buffer's item
116      * data type.
117      */
118     public void copy(Buf theSrc) {
119         if (theSrc == this) {
120         } else if (theSrc instanceof Unsigned16BitIntegerMatrixBuf) {
121             Unsigned16BitIntegerMatrixBuf src
122                     = (Unsigned16BitIntegerMatrixBuf) theSrc;
123             ReduceArrays.reduce(src.myMatrix, src.myRowRange, src.myColRange,
124                     this.myMatrix, this.myRowRange, this.myColRange,
125                     myOp);
126         } else {
127             Unsigned16BitIntegerBuf.defaultCopy((Unsigned16BitIntegerBuf) theSrc, this);
128         }
129     }
130 
131     /**
132      * {@inheritDoc}
133      *
134      * Create a buffer for performing parallel reduction using the given binary
135      * operation. The results of the reduction are placed into this buffer.
136      * @exception ClassCastException (unchecked exception) Thrown if this
137      * buffer's element data type and the given binary operation's argument data
138      * type are not the same.
139      */
140     public Buf getReductionBuf(Op op) {
141         throw new UnsupportedOperationException();
142     }
143 
144 // Hidden operations.
145     /**
146      * {@inheritDoc}
147      *
148      * Receive as many items as possible from the given byte buffer to this
149      * buffer.
150      * <P>
151      * The <code>receiveItems()</code> method must not block the calling thread; if
152      * it does, all message I/O in MP will be blocked.
153      */
154     protected int receiveItems(int i,
155             int num,
156             ByteBuffer buffer) {
157         ShortBuffer shortbuffer = buffer.asShortBuffer();
158         num = Math.min(num, shortbuffer.remaining());
159         int n = 0;
160         int r = i2r(i);
161         int row = r + myLowerRow;
162         int c = i2c(i);
163         int col = c + myLowerCol;
164         int ncols = Math.min(myColCount - c, num);
165         while (r < myRowCount && ncols > 0) {
166             int[] myMatrix_row = myMatrix[row];
167             for (c = 0; c < ncols; ++c) {
168                 myMatrix_row[col]
169                         = myOp.op(myMatrix_row[col], shortbuffer.get() & 0xFFFF);
170                 ++col;
171             }
172             num -= ncols;
173             n += ncols;
174             ++r;
175             ++row;
176             col = myLowerCol;
177             ncols = Math.min(myColCount, num);
178         }
179         buffer.position(buffer.position() + 2 * n);
180         return n;
181     }
182 
183 }