├── .idea
    ├── .gitignore
    ├── libraries
    │   └── lib.xml
    ├── misc.xml
    └── modules.xml
├── Lab7.iml
├── out
    └── production
    │   └── Lab7
    │       └── Main.class
└── src
    └── Main.java


/.idea/.gitignore:
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1 | # Default ignored files
2 | /shelf/
3 | /workspace.xml
4 | 


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/.idea/libraries/lib.xml:
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 1 | <component name="libraryTable">
 2 |   <library name="lib">
 3 |     <CLASSES>
 4 |       <root url="file://C:/mpj/lib" />
 5 |     </CLASSES>
 6 |     <JAVADOC />
 7 |     <SOURCES />
 8 |     <jarDirectory url="file://C:/mpj/lib" recursive="false" />
 9 |   </library>
10 | </component>


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/.idea/misc.xml:
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1 | <?xml version="1.0" encoding="UTF-8"?>
2 | <project version="4">
3 |   <component name="ProjectRootManager" version="2" languageLevel="JDK_17" default="true" project-jdk-name="17" project-jdk-type="JavaSDK">
4 |     <output url="file://$PROJECT_DIR$/out" />
5 |   </component>
6 | </project>


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/.idea/modules.xml:
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1 | <?xml version="1.0" encoding="UTF-8"?>
2 | <project version="4">
3 |   <component name="ProjectModuleManager">
4 |     <modules>
5 |       <module fileurl="file://$PROJECT_DIR$/Lab7.iml" filepath="$PROJECT_DIR$/Lab7.iml" />
6 |     </modules>
7 |   </component>
8 | </project>


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/Lab7.iml:
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 1 | <?xml version="1.0" encoding="UTF-8"?>
 2 | <module type="JAVA_MODULE" version="4">
 3 |   <component name="NewModuleRootManager" inherit-compiler-output="true">
 4 |     <exclude-output />
 5 |     <content url="file://$MODULE_DIR$">
 6 |       <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
 7 |     </content>
 8 |     <orderEntry type="inheritedJdk" />
 9 |     <orderEntry type="sourceFolder" forTests="false" />
10 |     <orderEntry type="library" name="lib" level="project" />
11 |   </component>
12 | </module>


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/out/production/Lab7/Main.class:
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https://raw.githubusercontent.com/Sanek192319/ParallelProgrammingLab_7/d590ed5e0682f8c3c5c44dd18fcad54f3f7295a2/out/production/Lab7/Main.class


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/src/Main.java:
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 1 | import mpi.MPI;
 2 | 
 3 | public class Main {
 4 |     private static final int rowsA = 4;
 5 |     private static final int colsA = 4;
 6 |     private static final int colsB = 4;
 7 |     private static final int MASTER = 0;
 8 |     public static void main(String[] args) {
 9 |         double[][] a = new double[rowsA][colsA];
10 |         double[][] b = new double[colsA][colsB];
11 |         double[][] c = new double[rowsA][colsB];
12 |         MPI.Init(args);
13 |         int numTasks = MPI.COMM_WORLD.Size();
14 |         int rank = MPI.COMM_WORLD.Rank();
15 | 
16 |         if (numTasks < 2) {
17 |             System.out.println("Need at least two MPI tasks. Quitting...\n");
18 |             MPI.COMM_WORLD.Abort(1);
19 |         }
20 |         long start = 0;
21 |         if(rank == MASTER) {
22 |             a = InputMautix(rowsA,colsA,1);
23 | 
24 |             b = InputMautix(colsA,colsB,1);
25 |             start = System.currentTimeMillis();
26 |         }
27 |         int rowsPerThread = rowsA / numTasks;
28 |         int extra = rowsA % numTasks;
29 | 
30 |         int[] rowsCounts = new int[numTasks];
31 |         int[] offsetCounts = new int[numTasks];
32 |         for(int i = 0; i < numTasks; i++) {
33 |             rowsCounts[i] = i < extra ? rowsPerThread + 1 : rowsPerThread;
34 |             offsetCounts[i] = i == MASTER ? 0 : offsetCounts[i-1] + rowsCounts[i-1];
35 |         }
36 | 
37 |         int rowsForThisTask = rowsCounts[rank];
38 |         double[][] aRows = new double[rowsForThisTask][colsA];
39 |         MPI.COMM_WORLD.Scatterv(
40 |                 a, 0, rowsCounts, offsetCounts,MPI.OBJECT,
41 |                 aRows, 0, rowsForThisTask, MPI.OBJECT,
42 |                 MASTER
43 |         );
44 |         MPI.COMM_WORLD.Bcast(b, 0, colsA, MPI.OBJECT, MASTER);
45 | 
46 |         double[][] cRows = new double[rowsForThisTask][colsB];
47 |         for (int k = 0; k < colsB; k++) {
48 |             for (int i = 0; i < rowsForThisTask; i++) {
49 |                 for (int j = 0; j < colsA; j++) {
50 |                     cRows[i][k] += aRows[i][j] * b[j][k];
51 |                 }
52 |             }
53 |         }
54 | 
55 |         MPI.COMM_WORLD.Allgatherv(
56 |                 cRows, 0, rowsForThisTask, MPI.OBJECT,
57 |                 c, 0, rowsCounts, offsetCounts, MPI.OBJECT
58 |         );
59 | 
60 |         if (rank == MASTER) {
61 |             var endTime = System.currentTimeMillis();
62 |             var dur = endTime - start;
63 | 
64 |             for(int i = 0; i < rowsA; i++) {
65 |                 for (int j = 0; j < colsB; j++) {
66 |                     System.out.print(c[i][j] +" ");
67 |                 }
68 |                 System.out.print('\n');
69 |             }
70 |             System.out.println("End with time: " + dur + " ms");
71 |         }
72 |         MPI.Finalize();
73 |     }
74 |     public static double[][] InputMautix(int rows,int cols,double value)
75 |     {
76 |         double[][] result = new double[rows][cols];
77 |         for(int i = 0; i < rows; i++) {
78 |             for (int j = 0; j < cols; j++) {
79 |                 result[i][j] = value;
80 |             }
81 |         }
82 |         return result;
83 |     }
84 | }


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