MPI

Author: Abd-ELrahmanHamza

MPI/.idea/.gitignore

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+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
+    </content>
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+    <orderEntry type="library" name="lib" level="project" />
+  </component>
+</module>

MPI/.idea/libraries/lib.xml

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+1 2 3
+4 5 6
+7 8 9

MPI/.idea/misc.xml

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+import mpi.MPI;
+
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.FileReader;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Scanner;
+
+public class InvertibleMatrix {
+    private static int[] matrix;
+
+    public static void main(String[] args) throws IOException {
+        MPI.Init(args);
+        int my_rank = MPI.COMM_WORLD.Rank();
+        int root = 0;
+        matrix = new int[9];
+        int[] sendBuffer = new int[1];
+        int[] receiveBuffer = new int[4];
+
+        // TODO: Read the file by the root
+        if (my_rank == root) {
+            readFile();
+            System.out.println("process " + my_rank + " matrix values after reading file " + Arrays.toString(matrix));
+        } else {
+            System.out.println("process " + my_rank + " matrix values before Bcast " + Arrays.toString(matrix));
+        }
+
+        // TODO: broadcast the matrix
+        MPI.COMM_WORLD.Bcast(matrix, 0, 9, MPI.INT, root);
+        System.out.println("process " + my_rank + " matrix values after Bcast " + Arrays.toString(matrix));
+
+        // TODO: calculate the values
+        if (my_rank != root) {
+            int[][] mat2d = new int[3][3];
+            //                         0 1 2               [0][r-1]     [1][]       [2]         [2]         [1]
+            //0*3+0 0*3+1 0*3+2      0 0 1 2          mat2d[0][0]*(mat2d[1][1]*mat2d[2][2]-mat2d[2][1]*mat2d[1][2])
+            //1*3+0 1*3+1 1*3+2      1 3 4 5        - mat2d[0][1]*(mat2d[1][0]*mat2d[2][2]-mat2d[2][0]*mat2d[1][2])
+            //2*3+0 2*3+1 2*3+2      2 6 7 8          mat2d[0][2]*(mat2d[1][0]*mat2d[2][1]-mat2d[2][0]*mat2d[1][1])
+            // TODO: Convert the 1d array into 2d array
+            for (int i = 0; i < 3; i++) {
+                for (int j = 0; j < 3; j++) {
+                    mat2d[i][j] = matrix[(i * 3) + j];
+                }
+            }
+            System.out.println("process " + my_rank + " matrix values after converting 1d into 2d " + Arrays.deepToString(mat2d));
+            sendBuffer[0] = 0;
+
+            // TODO: calculate the values
+            if (my_rank == 1) {
+                sendBuffer[0] = mat2d[0][0] * (mat2d[1][1] * mat2d[2][2] - mat2d[2][1] * mat2d[1][2]);
+            } else if (my_rank == 2) {
+                sendBuffer[0] = -mat2d[0][1] * (mat2d[1][0] * mat2d[2][2] - mat2d[2][0] * mat2d[1][2]);
+            } else {
+                sendBuffer[0] = mat2d[0][2] * (mat2d[1][0] * mat2d[2][1] - mat2d[2][0] * mat2d[1][1]);
+            }
+            System.out.println("process " + my_rank + " my value is " + sendBuffer[0]);
+        }
+        // TODO: Gather the values
+        MPI.COMM_WORLD.Gather(sendBuffer, 0, 1, MPI.INT, receiveBuffer, 0, 1, MPI.INT, root);
+        if (my_rank == root) {
+            System.out.println("I am the root & I have received: " + Arrays.toString(receiveBuffer));
+
+            // TODO: determine whether the matrix is singular or not
+            int sum = Arrays.stream(receiveBuffer).sum();
+            if (sum == 0) {
+                System.out.println("The determinant is " + sum + " so the matrix is singular");
+            } else {
+                System.out.println("The determinant is " + sum + " so the matrix is not singular");
+            }
+        }
+        MPI.Finalize();
+    }
+
+    private static void readFile() throws IOException {
+        Scanner scanner = new Scanner(new File("matrix.txt"));
+        int i = 0;
+        while (scanner.hasNextInt()) {
+            matrix[i++] = scanner.nextInt();
+        }
+    }
+}