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

typedef struct Complex_s
{
  double x,y;
} Complex;

void proba(int *x, int *y, int *len, MPI_Datatype * type)
{
    int i;
    for(i = 0; i < *len; i++)
    {
	*y += (*x);
	x++;
	y++;
    }
}

void opp_complex(Complex *c1, Complex *c2, int *len, MPI_Datatype * type)
{
  int i;
  for(i = 0; i < *len; i++)
  {
     // if((c1->x > c2->x) || ((c1->x == c2->x) && (c1->y > c2->y)))
	//*c2 = *c1;
    (c2->x) += (c1->x);
    (c2->y) += (c1->y);
     c1++;
     c2++;
  }
}

int main(int argc, char *argv[])
{
    MPI_Status status;
    int id, np, err;
    int a, i;
    MPI_Op opp, mpi_opp_complex;
    MPI_Datatype typeComplex;

    err = MPI_Init(&argc, &argv);

    MPI_Comm_size(MPI_COMM_WORLD, &np);
    MPI_Comm_rank(MPI_COMM_WORLD, &id);


    MPI_Type_contiguous(2, MPI_DOUBLE, &typeComplex);
    MPI_Type_commit(&typeComplex);

    MPI_Op_create((MPI_User_function *)proba, 1, &opp);

    a = id+10;
    MPI_Reduce(&a, &i, 1, MPI_INT, opp, 0, MPI_COMM_WORLD);

    printf("my id is %d, and a = %d\n", id, a);
    if(id == 0)
      printf("my id is %d, and i = %d\n", id, i);

    Complex aa,bb;
    aa.x = id;
    aa.y = id + 1;

    MPI_Op_create((MPI_User_function *)opp_complex, 1, &mpi_opp_complex);
    MPI_Reduce(&aa, &bb, 1, typeComplex, mpi_opp_complex, 0, MPI_COMM_WORLD);

    printf("aa.x = %lf, aa.y = %lf\n", aa.x, aa.y);

    if(id == 0)
    {
      printf("bb.x = %lf, bb.y = %lf\n", bb.x, bb.y);
    }


    Complex *cc, *rr;
    int n = 3;
    cc = (Complex*)malloc(n*sizeof(Complex));
    rr = (Complex*)malloc(n*sizeof(Complex));

    for(i = 0; i < n; i++)
    {
	cc[i].x = id*10+i;
	cc[i].y = id*100+i;
    }

    MPI_Reduce(cc, rr, n, typeComplex, mpi_opp_complex, 0, MPI_COMM_WORLD);

    if(id == 0)
    {
      for(i = 0; i < n; i++)
      printf("rr[%d].x = %lf, rr[%d].y = %lf\n", i, rr[i].x, i, rr[i].y);
    }

    MPI_Finalize();
}