Given two matrices, A and B, where matrix A contains M rows and K columns and ma

Question

Given two matrices, A and B, where matrix A contains M rows and K columns and matrix B contains K rows and N columns, the matrix product of A and B is matrix C, where C contains M rows and N columns. The entry in matrix C for row i, column j (Ci,j) is the sum of the products of the elements for row i in matrix A and column j in matrix B. That is,

C(i,j)  =  S( n=1 through K) A(i,n) * B(n,j)

For example, if A is a 3-by-2 matrix and B is a 2-by-3 matrix, element C3,1 is the sum of A3,1 * B1,1 and A3,2 * B2,1.

For this project, calculate each element C(i,j) of the matrix product C of two matrices A and B in a seperate thread. So the number of threads is equal to the number of terms in the matrix product. Use JAVA threads to implement this program. The matrices to be multiplied are:

Explanation / Answer

public class ParentTh {
    
   
    public static final int NUM_OF_THREADS = 9;
    
    public static void main(String args[])
    {
        int row;
        int col;
        int A[][] = {{1,4},{2,5},{3,6}};
        int B[][] = {{8,7,6},{5,4,3}};
        int C[][] = new int[3][3];
        int threadcount = 0;   
              Thread[] thrd = new Thread[NUM_OF_THREADS];
               

                try
                {
                   for(row = 0 ; row < 3; row++)
                   {
                        for (col = 0 ; col < 3; col++ )
                        {
                                // creating thread for multiplications
                             thrd[threadcount] = new Thread(new WorkerTh(row, col, A, B, C));
                             thrd[threadcount].start(); //thread start
                             
                             thrd[threadcount].join(); // joining threads
                              threadcount++;
                        }
                        
                   }
                  
                }
                catch (InterruptedException ie){}
                
                // printing matrix A
                System.out.println(" A Matrix : ");
              &n bsp; for(row = 0 ; row < 3; row++)
                {
                        for (col = 0 ; col < 2; col++ )
                        {
                            System.out.print(" "+A[row][col]);
                        }
                        System.out.println();
                 }
                
                // printing matrix B
                System.out.println(" B Matrix : ");
                for(row = 0 ; row < 2; row++)
                {
                        for (col = 0 ; col < 3; col++ )
                        {
                            System.out.print(" "+B[row][col]);
                        }
                        System.out.println();
                 }
                
                // printing resulting matrix C after multiplication
                System.out.println(" Resulting C Matrix : ");
                for(row = 0 ; row < 3; row++)
                {
                        for (col = 0 ; col < 3; col++ )
                        {
                            System.out.print(" "+C[row][col]);
                        }
                        System.out.println();
                 }
            
    }
    
}



class WorkerTh implements Runnable
{
    private int row;
    private int col;
    private int A[][];
    private int B[][];
    private int C[][];
    
    public WorkerTh(int row, int col, int A[][], int B[][], int C[][] )
    {
        this.row = row;
        this.col = col;
        this.A = A;
        this.B = B;
        this.C = C;
    }
    
    @Override
    public void run()
    {
       
       
            for(int k = 0; k < B.length; k++)
            {
             C[row][col] += A[row][k] * B[k][col];
            }
                     
    }
   
}

Related Questions

Navigate

• Browse (All)
• Browse G
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.