Lab3 - OpenMP

#include<stdio.h>
#include<stdlib.h>
#include <MPI.h>

#define MSG_SIZE 1
#define MSG_SUB_ARRAY 2
#define MSG_LOCAL_MINIMUM 3

int main(int argc, char* argv[])
{
    int partial, rank, size, arraysize, i;
    float min, temp;
    float* numbers;
    MPI_Status status;
    MPI_Init(&argc, &argv);
    MPI_Comm_rank(MPI_COMM_WORLD, &rank);
    MPI_Comm_size(MPI_COMM_WORLD, &size); //number of paralel units

    if (rank == 0) //master runs this
    {
        setvbuf(stdout, 0, _IONBF, 0); //no buffering
        printf("size: %d\nrank: %d\n\n", size, rank);
        do
        {
            printf("Duzina niza: ", size - 1);
            scanf("%d", &arraysize);
        } while (arraysize % (size - 1) != 0);

        //allocate number of floats
        numbers = (float*)calloc(arraysize, sizeof(float));

        printf("Unesi elemente.\n");

        for (i = 0; i<arraysize; i++)
        {
            printf("Element #%d: ", i + 1);
            scanf("%f", &numbers[i]);
        }

        partial = arraysize / (size - 1); //duzina mini niza

        for (i = 1; i<size; i++) //posalji 4 poruke sa duzinom niza
            MPI_Send(&partial, 1, MPI_INT, i, MSG_SIZE, MPI_COMM_WORLD);

        for (i = 1; i<size; i++) //posalji 4 poruke sa brojevima koje krecu od (i-1)*partial do partial.
            MPI_Send(numbers + (i - 1)*partial, partial, MPI_FLOAT, i, MSG_SUB_ARRAY, MPI_COMM_WORLD);

        //free memory
        free(numbers);

        //SADA POCINJE RECEIVE PART
        min = 9999999; //set min number to something big

        for (i = 0; i < size - 1; i++)
        {
            MPI_Recv(&temp, 1, MPI_FLOAT, MPI_ANY_SOURCE, MSG_LOCAL_MINIMUM, MPI_COMM_WORLD, &status);
            if (temp < min)
                min = temp;
        }

        printf("Konacni minumum: %.2f\n\n", min);

    }
    else //children run this
    {
        printf("\nRANK: %d\n", rank);
        MPI_Recv(&arraysize, 1, MPI_INT, 0, MSG_SIZE, MPI_COMM_WORLD, &status); //get the sub array length

        numbers = (float*)calloc(arraysize, sizeof(float)); //allocate the memory for the array

        MPI_Recv(numbers, arraysize, MPI_FLOAT, 0, MSG_SUB_ARRAY, MPI_COMM_WORLD, &status); //get the numbers of subarray

        //prikazi brojke
        for (i = 0; i<arraysize; i++)
            printf("%.2f ", numbers[i]);
        printf("\n");
        //nadji minimum
        min = numbers[0];
        for (i = 1; i<arraysize; i++)
            if (numbers[i] < min)
                min = numbers[i];

        printf("Lokalni minimum: %.2f\n", min);

        free(numbers);

        //send the computation
        MPI_Send(&min, 1, MPI_FLOAT, 0, MSG_LOCAL_MINIMUM, MPI_COMM_WORLD);
    }


    MPI_Finalize();

    return 0;
}