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1   //******************************************************************************
2   //
3   // File:    FloatMatrixBuf_1.java
4   // Package: edu.rit.mp.buf
5   // Unit:    Class edu.rit.mp.buf.FloatMatrixBuf_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.
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25  // permission to link this library with independent modules to produce an
26  // executable, regardless of the license terms of these independent modules, and
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30  // which is not derived from or based on this library. If you modify this library,
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33  // statement from your version.
34  //
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 java.nio.ByteBuffer;
43  import java.nio.FloatBuffer;
44  
45  import edu.rit.mp.Buf;
46  import edu.rit.pj.reduction.FloatOp;
47  import edu.rit.pj.reduction.Op;
48  import edu.rit.util.Range;
49  
50  /**
51   * Class FloatMatrixBuf_1 provides a buffer for a matrix of float items sent or
52   * received using the Message Protocol (MP). The matrix row and column strides
53   * must both be 1. While an instance of class FloatMatrixBuf_1 may be
54   * constructed directly, normally you will use a factory method in class
55   * {@linkplain edu.rit.mp.FloatBuf FloatBuf}. See that class for further
56   * information.
57   *
58   * @author Alan Kaminsky
59   * @version 05-Apr-2009
60   */
61  public class FloatMatrixBuf_1
62          extends FloatMatrixBuf {
63  
64  // Exported constructors.
65      /**
66       * Construct a new float matrix buffer. It is assumed that the rows and
67       * columns of <code>theMatrix</code> are allocated and that each row of
68       * <code>theMatrix</code> has the same number of columns.
69       *
70       * @param theMatrix Matrix.
71       * @param theRowRange Range of rows to include. The stride is assumed to be
72       * 1.
73       * @param theColRange Range of columns to include. The stride is assumed to
74       * be 1.
75       */
76      public FloatMatrixBuf_1(float[][] theMatrix,
77              Range theRowRange,
78              Range theColRange) {
79          super(theMatrix, theRowRange, theColRange);
80      }
81  
82  // Exported operations.
83      /**
84       * {@inheritDoc}
85       *
86       * Obtain the given item from this buffer.
87       * <P>
88       * The <code>get()</code> method must not block the calling thread; if it does,
89       * all message I/O in MP will be blocked.
90       */
91      public float get(int i) {
92          return myMatrix[i2r(i) + myLowerRow][i2c(i) + myLowerCol];
93      }
94  
95      /**
96       * {@inheritDoc}
97       *
98       * Store the given item in this buffer.
99       * <P>
100      * The <code>put()</code> method must not block the calling thread; if it does,
101      * all message I/O in MP will be blocked.
102      */
103     public void put(int i,
104             float item) {
105         myMatrix[i2r(i) + myLowerRow][i2c(i) + myLowerCol] = item;
106     }
107 
108     /**
109      * {@inheritDoc}
110      *
111      * Create a buffer for performing parallel reduction using the given binary
112      * operation. The results of the reduction are placed into this buffer.
113      * @exception ClassCastException (unchecked exception) Thrown if this
114      * buffer's element data type and the given binary operation's argument data
115      * type are not the same.
116      */
117     public Buf getReductionBuf(Op op) {
118         return new FloatMatrixReductionBuf_1(myMatrix, myRowRange, myColRange, (FloatOp) op);
119     }
120 
121 // Hidden operations.
122     /**
123      * {@inheritDoc}
124      *
125      * Send as many items as possible from this buffer to the given byte buffer.
126      * <P>
127      * The <code>sendItems()</code> method must not block the calling thread; if it
128      * does, all message I/O in MP will be blocked.
129      */
130     protected int sendItems(int i,
131             ByteBuffer buffer) {
132         FloatBuffer floatbuffer = buffer.asFloatBuffer();
133         int n = 0;
134         int r = i2r(i);
135         int row = r + myLowerRow;
136         int c = i2c(i);
137         int col = c + myLowerCol;
138         int ncols = Math.min(myColCount - c, floatbuffer.remaining());
139         while (r < myRowCount && ncols > 0) {
140             floatbuffer.put(myMatrix[row], col, ncols);
141             n += ncols;
142             ++r;
143             ++row;
144             c = 0;
145             col = myLowerCol;
146             ncols = Math.min(myColCount, floatbuffer.remaining());
147         }
148         buffer.position(buffer.position() + 4 * n);
149         return n;
150     }
151 
152     /**
153      * {@inheritDoc}
154      *
155      * Receive as many items as possible from the given byte buffer to this
156      * buffer.
157      * <P>
158      * The <code>receiveItems()</code> method must not block the calling thread; if
159      * it does, all message I/O in MP will be blocked.
160      */
161     protected int receiveItems(int i,
162             int num,
163             ByteBuffer buffer) {
164         FloatBuffer floatbuffer = buffer.asFloatBuffer();
165         num = Math.min(num, floatbuffer.remaining());
166         int n = 0;
167         int r = i2r(i);
168         int row = r + myLowerRow;
169         int c = i2c(i);
170         int col = c + myLowerCol;
171         int ncols = Math.min(myColCount - c, num);
172         while (r < myRowCount && ncols > 0) {
173             floatbuffer.get(myMatrix[row], col, ncols);
174             num -= ncols;
175             n += ncols;
176             ++r;
177             ++row;
178             col = myLowerCol;
179             ncols = Math.min(myColCount, num);
180         }
181         buffer.position(buffer.position() + 4 * n);
182         return n;
183     }
184 
185 }