gistfile1.txt

#include <stdio.h>
#include <mpi.h>
#include <string.h>
#include <stdlib.h>

int main(int argc, char* argv[]){
    int rank, size, i, j, k, tag = 0;

    MPI_Status status;
    MPI_Init(&argc, &argv );
    MPI_Comm_rank(MPI_COMM_WORLD, &rank);
    MPI_Comm_size(MPI_COMM_WORLD, &size);

    double start_time,final_time;

    // Set matrices lines and columns
    int lines = 10;
    int columns = 10;

    start_time = MPI_Wtime();

    // double *receive = malloc(sizeof(double) * columns);

    double *matrix_line = malloc(sizeof(double) * lines);


    // initialize the matrix_b
    double** matrix_b = (double**) malloc(sizeof(double*) * lines);
    matrix_b[0] = (double*) malloc(lines * columns * sizeof(double));
    for(i=1; i<lines; i++)
        matrix_b[i] = &(matrix_b[0][i*columns]);

    for(i = 0; i < lines; i++){
        for(j = 0; j < columns; j++){
           matrix_b[i][j] = (double) j;
        }
    }

    // final matrix
    double** final_matrix = (double**) malloc(sizeof(double*) * lines);
    final_matrix[0] = (double*) malloc(lines * columns * sizeof(double));
    for(i=1; i<lines; i++)
        final_matrix[i] = &(final_matrix[0][i*columns]);

    if(size > 1){

        int partial = lines / (size -1);
        printf("PARTIAL: %d", partial);

        if (rank == 0){

            double** matrix_a = (double**) malloc(sizeof(double*) * lines);
            matrix_a[0] = (double*) malloc(lines * columns * sizeof(double));
            for(i=1; i<lines; i++)
                matrix_a[i] = &(matrix_a[0][i*columns]);

            for(i = 0; i < lines; i++){
                for(j = 0; j < columns; j++){
                   matrix_a[i][j] = (double) j;
                }
            }


            // double** receive_partial_matrix = (double**) malloc(sizeof(double*) * partial);
            // receive_partial_matrix[0] = (double*) malloc(partial * columns * sizeof(double));
            // for(i=1; i<lines; i++)
            //     receive_partial_matrix[i] = &(receive_partial_matrix[0][i*columns]);


            int count = 0;
            for(j = 1; j < size; j++){
                // Receive partial to calculate
                // double** receive_partial = (double**) malloc(sizeof(double*) * partial);
                // receive_partial[0] = (double*) malloc(partial * columns * sizeof(double));
                // for(i=1; i<lines; i++)
                //     receive_partial[i] = &(receive_partial[0][i*columns]);

                printf("COUNT: %d\n", count);
                MPI_Send(&matrix_a[count][0], partial * columns, MPI_DOUBLE, j, tag, MPI_COMM_WORLD);
                MPI_Recv(&final_matrix[count][0], partial * columns, MPI_DOUBLE, j, tag, MPI_COMM_WORLD, &status);
                count += partial;

            }

            final_time = MPI_Wtime();
            printf("Time: %f\n", final_time - start_time);

        } else {

            double** receive = (double**) malloc(sizeof(double*) * partial);
            receive[0] = (double*) malloc(partial * columns * sizeof(double));
            for(i=1; i<lines; i++)
                receive[i] = &(receive[0][i*columns]);

            double** partial_matrix = (double**) malloc(sizeof(double*) * partial);
            partial_matrix[0] = (double*) malloc(partial * columns * sizeof(double));
            for(i=1; i<lines; i++)
                partial_matrix[i] = &(partial_matrix[0][i*columns]);

            double *line = malloc(sizeof(double) * lines);
            printf("PARTIAL => %d", partial);
            MPI_Recv(&receive[0][0], partial * columns, MPI_DOUBLE, 0, tag, MPI_COMM_WORLD, &status);

            double partial_counter = 0.0;
            for(k = 0; k < partial; k++){
                for(i = 0; i < partial; i++){
                    for(j = 0; j < columns; j++){
                        // printf("%d * %d + ", receive[j], matrix_b[j][i]);
                        partial_counter += receive[k][j] * matrix_b[j][i];
                    }
                    // printf("PARTIAL: %d\n", partial);
                    line[i] = partial_counter;
                    partial_counter = 0.0;
                }
                partial_matrix[k] = matrix_line;
            }

            MPI_Send(&partial_matrix[0][0], partial * columns, MPI_DOUBLE, 0, tag, MPI_COMM_WORLD);

        }

    } else {

        double** matrix_a = (double**) malloc(sizeof(double*) * lines);
        matrix_a[0] = (double*) malloc(lines * columns * sizeof(double));
        for(i=1; i<lines; i++)
            matrix_a[i] = &(matrix_a[0][i*columns]);

        for(i = 0; i < lines; i++){
            for(j = 0; j < columns; j++){
               matrix_a[i][j] = (double) j;
            }
        }
        double partial = 0.0;
        for(k = 0; k < lines; k++){
            for(i = 0; i < lines; i++){
                for(j = 0; j < columns; j++){
                    // printf("%d * %d + ", receive[j], matrix_b[j][i]);
                    partial += matrix_a[k][j] * matrix_b[j][i];
                }
                // printf("PARTIAL: %d\n", partial);
                matrix_line[i] = partial;
                partial = 0;
            }
            final_matrix[k] = matrix_line;
        }

        // // Show matrix
        // for(i = 0; i < lines; i++){
        //     for(j = 0; j < columns; j++){
        //         printf("%f,", final_matrix[i][j]);
        //     }
        //     printf("\n");
        // }

        final_time = MPI_Wtime();
        printf("Time: %f\n", final_time - start_time);

    }

    MPI_Finalize();
}