[23.05][PRR]listing 5,6

/*
export PATH=$PATH:/usr/lib64/mpi/gcc/openmpi/bin
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/lib64/psm2

mpicc -o main main.c
mpirun main

export PATH=$PATH:/usr/lib64/mpi/gcc/openmpi/bin
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/lib64/psm2

mpicc -o main main.c
mpirun --mca pml ob1 --mca btl self,tcp main

//===========linijka do polaczenia sie z komputerami
for i in `seq 11 25`; do ssh 10.16.121.$i mkdir cokolwiek "echo ok"; done
//==================================================

*/

#include <iostream>
#include <stdlib.h>
#include <mpi.h>

using namespace std;

void safePrintArray(int rank, int nProc, int *array, int size){
    int i, n;
    for(n=0;n<nProc;n++){
        int id = n;
        if(id == rank){
            printf(" %d : ", id);
            for(i=0; i<size; i++)
                printf(" %d ", array[i]);
            printf("\n");
        }
        MPI_Barrier(MPI_COMM_WORLD);
    }
}

int main(int argc, char **argv)
{
    int id;
    int size;
    int root;
    int buf[10];
    int reducebuf[10] = {0};
    int *sendbuf;
    int i;

    MPI_Init(&argc, &argv);
    MPI_Comm_rank(MPI_COMM_WORLD, &id);
    MPI_Comm_size(MPI_COMM_WORLD, &size);

    for(i=0; i<10; i++)
        buf[i] = i%(id+1);

    safePrintArray(id, size, buf, 10);

    if (id==0) printf("\n\n");
    fflush(stdout);
    MPI_Barrier(MPI_COMM_WORLD);

    root = 0;
    MPI_Reduce(buf, reducebuf, 10, MPI_INT, MPI_MAX, root, MPI_COMM_WORLD);
    //MPI_Allreduce(buf, reducebuf,) 10, MPI_INIT, MPI_MAX, MPI_COMM_WORLD);

    safePrintArray(id, size, reducebuf, 10);

    MPI_Finalize();
    return 0;
}

//LISTING 6================================================

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

int main(int argc, char **argv){
    int my_rank, p;
    int i,n;
    double my_pi, pi, h, sum, x;

    if(argc<2){
        printf("Poprawne użycie programu: program liczba_przedzialow calkowania\n");
        exit(1);
    }
    MPI_Init(&argc, &argv);
    MPI_Comm_rank(MPI_COMM_WORLD, &my_rank);
    MPI_Comm_size(MPI_COMM_WORLD, &p);

    if(my_rank == 0)
        n=atoi(argv[1]);

    MPI_Bcast(&n, 1, MPI_INT, 0, MPI_COMM_WORLD);

    h=1.0/(double)n;
    /*Całka metodą trapezów*/
    sum=0.0;
    for (i=my_rank; i<n; i+=p){
        x=h*((double)i+0.5);
        sum+=4.0/(1.0+x*x);
    }
    my_pi=h*sum;

    MPI_Reduce(&my_pi, &pi, 1, MPI_DOUBLE, MPI_SUM, 0, MPI_COMM_WORLD);

    if(my_rank == 0)
        printf("pi=%.16f\n", pi);

    MPI_Finalize();
}