1 //******************************************************************************
2 //
3 // File: ObjectMatrixBuf.java
4 // Package: edu.rit.mp.buf
5 // Unit: Class edu.rit.mp.buf.ObjectMatrixBuf
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 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.util.Arrays;
47 import edu.rit.util.Range;
48
49 /**
50 * Class ObjectMatrixBuf provides a buffer for a matrix of object items sent or
51 * received using the Message Protocol (MP). The matrix row and column strides
52 * may be 1 or greater than 1. While an instance of class ObjectMatrixBuf may be
53 * constructed directly, normally you will use a factory method in class
54 * {@linkplain edu.rit.mp.ObjectBuf ObjectBuf}. See that class for further
55 * information.
56 *
57 * @param <T> Data type of the objects in the buffer.
58 * @author Alan Kaminsky
59 * @version 23-Mar-2009
60 */
61 @SuppressWarnings("unchecked")
62 public class ObjectMatrixBuf<T>
63 extends ObjectBuf<T> {
64
65 // Hidden data members.
66 T[][] myMatrix;
67 Range myRowRange;
68 Range myColRange;
69 int myLowerRow;
70 int myRowCount;
71 int myRowStride;
72 int myLowerCol;
73 int myColCount;
74 int myColStride;
75
76 // Exported constructors.
77 /**
78 * Construct a new object matrix buffer. It is assumed that the rows and
79 * columns of <code>theMatrix</code> are allocated and that each row of
80 * <code>theMatrix</code> has the same number of columns.
81 *
82 * @param theMatrix Matrix.
83 * @param theRowRange Range of rows to include.
84 * @param theColRange Range of columns to include.
85 */
86 public ObjectMatrixBuf(T[][] theMatrix,
87 Range theRowRange,
88 Range theColRange) {
89 super(theRowRange.length() * theColRange.length());
90 myMatrix = theMatrix;
91 myRowRange = theRowRange;
92 myColRange = theColRange;
93 myLowerRow = theRowRange.lb();
94 myRowCount = theRowRange.length();
95 myRowStride = theRowRange.stride();
96 myLowerCol = theColRange.lb();
97 myColCount = theColRange.length();
98 myColStride = theColRange.stride();
99 }
100
101 // Exported operations.
102 /**
103 * {@inheritDoc}
104 *
105 * Obtain the given item from this buffer.
106 * <P>
107 * The <code>get()</code> method must not block the calling thread; if it does,
108 * all message I/O in MP will be blocked.
109 */
110 public T get(int i) {
111 return myMatrix[i2r(i) * myRowStride + myLowerRow][i2c(i) * myColStride + myLowerCol];
112 }
113
114 /**
115 * Store the given item in this buffer.
116 * <P>
117 * The <code>put()</code> method must not block the calling thread; if it does,
118 * all message I/O in MP will be blocked.
119 *
120 * @param i Item index in the range 0 .. <code>length()</code>-1.
121 * @param item Item to be stored at index <code>i</code>.
122 */
123 public void put(int i,
124 T item) {
125 myMatrix[i2r(i) * myRowStride + myLowerRow][i2c(i) * myColStride + myLowerCol] = item;
126 reset();
127 }
128
129 /**
130 * {@inheritDoc}
131 *
132 * Copy items from the given buffer to this buffer. The number of items
133 * copied is this buffer's length or <code>theSrc</code>'s length, whichever is
134 * smaller. If <code>theSrc</code> is this buffer, the <code>copy()</code> method
135 * does nothing.
136 * @exception ClassCastException (unchecked exception) Thrown if
137 * <code>theSrc</code>'s item data type is not the same as this buffer's item
138 * data type.
139 */
140 public void copy(Buf theSrc) {
141 if (theSrc == this) {
142 } else if (theSrc instanceof ObjectMatrixBuf) {
143 ObjectMatrixBuf<T> src = (ObjectMatrixBuf<T>) theSrc;
144 Arrays.copy(src.myMatrix, src.myRowRange, src.myColRange,
145 this.myMatrix, this.myRowRange, this.myColRange);
146 reset();
147 } else {
148 ObjectBuf.defaultCopy((ObjectBuf<T>) theSrc, this);
149 reset();
150 }
151 }
152
153 /**
154 * {@inheritDoc}
155 *
156 * Create a buffer for performing parallel reduction using the given binary
157 * operation. The results of the reduction are placed into this buffer.
158 * @exception ClassCastException (unchecked exception) Thrown if this
159 * buffer's element data type and the given binary operation's argument data
160 * type are not the same.
161 */
162 public Buf getReductionBuf(Op op) {
163 return new ObjectMatrixReductionBuf<T>(myMatrix, myRowRange, myColRange, (ObjectOp<T>) op, this);
164 }
165
166 // Hidden operations.
167 /**
168 * Convert the given buffer index to a row index.
169 */
170 int i2r(int i) {
171 return myColCount == 0 ? i : i / myColCount;
172 }
173
174 /**
175 * Convert the given buffer index to a column index.
176 */
177 int i2c(int i) {
178 return myColCount == 0 ? 0 : i % myColCount;
179 }
180
181 }