08.09.2016.3.c

#include <mpi.h>
#include <stdio.h>
#define W MPI_COMM_WORLD

void printArray(int n, int array[n], int rank) {
  for (int i = 0; i < n; i++) {
    if (rank == -1) printf("%4d ", array[i]);
    else printf("{%d}%4d ", rank, array[i]);
  }
  printf("\n");
}

void printMatrix(int n, int m, int matrix[n][m], int rank) {
  for (int i = 0; i < n; i++) {
    printArray(m, matrix[i], rank);
  }
}

int main(int argc, char** argv) {
  MPI_Init(&argc, &argv);
  int rank, size;
  MPI_Comm_rank(W, &rank);
  MPI_Comm_size(W, &size);

  int n = 6;
  int k = 2;
  int A[n][n], B[n][n], C[n][n],
      locA[n][k], locB[k][n], locC[n][n];

  // Inicijalizacija matrica A i B
  if (rank == 0) {
    for (int i = 0; i < n; i++) {
      for (int j = 0; j < n; j++) {
        A[i][j] = i * 10 + j;
        B[i][j] = i * 10 + j;
      }
    }
  }

  // Definicija tipa za slanje kolona
  MPI_Datatype MPI_COL;
  MPI_Type_vector(n, k, n, MPI_INT, &MPI_COL);
  MPI_Type_create_resized(MPI_COL, 0, k * sizeof(int), &MPI_COL);
  MPI_Type_commit(&MPI_COL);

  // Rasporedjuju se kolone matrice A i vrste matrice B
  MPI_Scatter(A, 1, MPI_COL, locA, n*k, MPI_INT, 0, W);
  MPI_Scatter(B, n*k, MPI_INT, locB, n*k, MPI_INT, 0, W);

  // Svaki proces lokalno cuva deo koji moze da izracuna.
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < n; j++) {
      locC[i][j] = 0;
      for (int q = 0; q < k; q++) {
        locC[i][j] += locA[i][q] * locB[q][j];
      }
    }
  }

  // Sabiramo sve parcijalne matrice, saljemo masteru.
  MPI_Reduce(locC, C, n * n, MPI_INT, MPI_SUM, 0, W);

  // Master prikazuje matricu.
  if (rank == 0) {
    printMatrix(n, n, C, -1);
  }

  MPI_Finalize();
  return 0;
}