View Javadoc
1   //******************************************************************************
2   //
3   // File:    FloatMatrixReductionBuf_1.java
4   // Package: edu.rit.mp.buf
5   // Unit:    Class edu.rit.mp.buf.FloatMatrixReductionBuf_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
14  // version 3 of the License, or (at your option) any later version.
15  //
16  // PJ is distributed in the hope that it will be useful, but WITHOUT ANY
17  // WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
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
22  // General Public License cover the whole combination.
23  //
24  // As a special exception, the copyright holders of this library give you
25  // permission to link this library with independent modules to produce an
26  // executable, regardless of the license terms of these independent modules, and
27  // to copy and distribute the resulting executable under terms of your choice,
28  // provided that you also meet, for each linked independent module, the terms
29  // and conditions of the license of that module. An independent module is a module
30  // which is not derived from or based on this library. If you modify this library,
31  // you may extend this exception to your version of the library, but you are not
32  // obligated to do so. If you do not wish to do so, delete this exception
33  // statement from your version.
34  //
35  // A copy of the GNU General Public License is provided in the file gpl.txt. You
36  // may also obtain a copy of the GNU General Public License on the World Wide
37  // Web at http://www.gnu.org/licenses/gpl.html.
38  //
39  //******************************************************************************
40  package edu.rit.mp.buf;
41  
42  import java.nio.ByteBuffer;
43  import java.nio.FloatBuffer;
44  
45  import edu.rit.mp.Buf;
46  import edu.rit.mp.FloatBuf;
47  import edu.rit.pj.reduction.FloatOp;
48  import edu.rit.pj.reduction.Op;
49  import edu.rit.pj.reduction.ReduceArrays;
50  import edu.rit.util.Range;
51  
52  /**
53   * Class FloatMatrixReductionBuf_1 provides a reduction buffer for class
54   * {@linkplain FloatMatrixBuf_1}.
55   *
56   * @author Alan Kaminsky
57   * @version 05-Apr-2009
58   */
59  class FloatMatrixReductionBuf_1
60          extends FloatMatrixBuf_1 {
61  
62  // Hidden data members.
63      FloatOp myOp;
64  
65  // Exported constructors.
66      /**
67       * Construct a new float matrix reduction buffer. It is assumed that the
68       * rows and columns of <code>theMatrix</code> are allocated and that each row of
69       * <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 FloatMatrixReductionBuf_1(float[][] theMatrix,
81              Range theRowRange,
82              Range theColRange,
83              FloatOp op) {
84          super(theMatrix, theRowRange, theColRange);
85          if (op == null) {
86              throw new NullPointerException("FloatMatrixReductionBuf_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             float 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 FloatMatrixBuf) {
121             FloatMatrixBuf src = (FloatMatrixBuf) theSrc;
122             ReduceArrays.reduce(src.myMatrix, src.myRowRange, src.myColRange,
123                     this.myMatrix, this.myRowRange, this.myColRange,
124                     myOp);
125         } else {
126             FloatBuf.defaultCopy((FloatBuf) theSrc, this);
127         }
128     }
129 
130     /**
131      * {@inheritDoc}
132      *
133      * Create a buffer for performing parallel reduction using the given binary
134      * operation. The results of the reduction are placed into this buffer.
135      * @exception ClassCastException (unchecked exception) Thrown if this
136      * buffer's element data type and the given binary operation's argument data
137      * type are not the same.
138      */
139     public Buf getReductionBuf(Op op) {
140         throw new UnsupportedOperationException();
141     }
142 
143 // Hidden operations.
144     /**
145      * {@inheritDoc}
146      *
147      * Receive as many items as possible from the given byte buffer to this
148      * buffer.
149      * <P>
150      * The <code>receiveItems()</code> method must not block the calling thread; if
151      * it does, all message I/O in MP will be blocked.
152      */
153     protected int receiveItems(int i,
154             int num,
155             ByteBuffer buffer) {
156         FloatBuffer floatbuffer = buffer.asFloatBuffer();
157         num = Math.min(num, floatbuffer.remaining());
158         int n = 0;
159         int r = i2r(i);
160         int row = r + myLowerRow;
161         int c = i2c(i);
162         int col = c + myLowerCol;
163         int ncols = Math.min(myColCount - c, num);
164         while (r < myRowCount && ncols > 0) {
165             float[] myMatrix_row = myMatrix[row];
166             for (c = 0; c < ncols; ++c) {
167                 myMatrix_row[col]
168                         = myOp.op(myMatrix_row[col], floatbuffer.get());
169                 ++col;
170             }
171             num -= ncols;
172             n += ncols;
173             ++r;
174             ++row;
175             col = myLowerCol;
176             ncols = Math.min(myColCount, num);
177         }
178         buffer.position(buffer.position() + 4 * n);
179         return n;
180     }
181 
182 }