//
//  main.cpp
//  Coded Computation
//
//  Created by Pardis Malekzadeh on 6/23/17.
//  Copyright © 2017 Pardis Malekzadeh. All rights reserved.
//

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

using namespace std;

const int n = 2;
const int p = 8;
const int ntasks = 4;
const int nsects = p/ntasks;
int req_results = 2;
double F[p][n];


void slave(int myrank){

    int x[n];
    cout << "Im a slave, my rank is"<<myrank<<"this is part 1"<<endl;

    /*MPI::COMM_WORLD.Recv(x, n, MPI::DOUBLE,0, myrank);*/
    MPI::COMM_WORLD.Bcast(x, n,
                          MPI::DOUBLE, 0);

    cout << "Im a slave, my rank is"<<myrank<<"this is part 2"<<endl;

    /////////////////
    double result[nsects];

    for (int i=0;i<nsects;i++){
        result[i]=0.0;
    }

    for (int i=0;i<nsects;i++){
        for (int j=0;j<n;j++){
            int StartIndex = (myrank-1)*nsects;
            result[i]+= F[StartIndex+i][j]*x[j];
        }
    }
    /////////////////

    MPI::COMM_WORLD.Send(result, nsects, MPI::DOUBLE, 0, myrank+ntasks);

    cout << "Im a slave, my rank is"<<myrank<<"this is part 3"<<endl;
}


void master(){
    double x[n];

    for (int i = 0; i < n; ++i)
    {
        x[i] = i;
    }


    /*for (int i = 0; i < n; ++i)
    {
        cin >> x[i];
    }*/

    cout << "Im master,this is part 1"<<endl;

    /*for (int rank = 1; rank <= ntasks; ++rank) {
        cout << "rank " << rank << endl;
        MPI::COMM_WORLD.Send(x, n, MPI::DOUBLE, rank, rank);


    }*/

    MPI::COMM_WORLD.Bcast(x, n,
                          MPI::DOUBLE, 0);

    cout << "Im master,this is part 2"<<endl;

    double result[100];
    for (int i = 0; i < p; ++i) {
        result[i] = 0;
    }

    for (int i = 0; i < p; ++i) {
        cout<<result[i];
    }
    MPI::Request    requests[ntasks];

    for (int rank = 1; rank <= ntasks; ++rank) {
        cout << (rank-1)*nsects << endl;
        requests[rank-1] = MPI::COMM_WORLD.Irecv(&result[(rank-1)*nsects], nsects, MPI::DOUBLE, rank, rank+ntasks);
    }


    cout << "Im master,this is part 3"<<endl;
    int recv_results = 0;

    do {
        for (int rank = 1; rank <= ntasks; ++rank) {
            if (requests[rank-1].Test())
                recv_results++;
        }
    } while (recv_results < req_results);


    cout << "Im master,this is part 4"<<endl;

}



int main(int argc, char* argv[]) {

    cout<< "Hello!" << '\n';

    for (int i = 0; i < p; ++i){
        for (int j = 0; j < n; ++j) {
            F[i][j] = rand() % 100 + 1;
        }
    }




    MPI::Init(argc, argv);

    int myrank = MPI::COMM_WORLD.Get_rank();

    int np = MPI::COMM_WORLD.Get_size();



    if (myrank == 0) {
        cout << "Running on "<< np << " Processes "<< '\n';
        master();

    } else {
        cout << "Greetings from process " << myrank << '\n';
        slave(myrank);
    }

    MPI::Finalize();
    return 0;
}