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gc.f90
program Groupedcalculations
	use mpi
	implicit none
	integer :: rank, nb_mpi_processes, ierror, tag, statu(MPI_STATUS_SIZE), n
	real(8) :: val, sum_val,mul_val,max_val,min_val, val0
	real(8), dimension(1:8) :: aval
	real(8), dimension(1:2) :: bval
	real(8), dimension(1:4) :: cval
 
	! Grouped calculations program
 
	call MPI_INIT( ierror )
	call MPI_COMM_SIZE( MPI_COMM_WORLD , nb_mpi_processes , ierror )
	call MPI_COMM_RANK( MPI_COMM_WORLD , rank , ierror )
 
	! REDUCE
 
	val = (rank + 1)*1.0d0
 
	call MPI_ALLREDUCE ( val , sum_val , 1 , MPI_DOUBLE_PRECISION , MPI_SUM , MPI_COMM_WORLD , ierror)
	call MPI_ALLREDUCE ( val , mul_val , 1 , MPI_DOUBLE_PRECISION , MPI_PROD , MPI_COMM_WORLD , ierror)
	call MPI_ALLREDUCE ( val , max_val , 1 , MPI_DOUBLE_PRECISION , MPI_MAX , MPI_COMM_WORLD , ierror)
	call MPI_ALLREDUCE ( val , min_val , 1 , MPI_DOUBLE_PRECISION , MPI_MIN , MPI_COMM_WORLD , ierror)
 
	! check
	print*, 'Process',rank,'I have the values',val,sum_val,mul_val,max_val,min_val
 
	! OTHERS
	val = 0.0d0
	if(rank==0) val = 7777.0d0
	call MPI_BCAST( val , 1 , MPI_DOUBLE_PRECISION , 0 , MPI_COMM_WORLD , ierror)
 
	! check
	print*, 'Process',rank,'after BCAST',val
 
	if(rank==3) then
		do n=1,8; aval(n) = n*10.0d0; end do
	end if
	call MPI_SCATTER( aval(1:8) , 2 , MPI_DOUBLE_PRECISION , bval(1:2) , 2 , MPI_DOUBLE_PRECISION , 3 , MPI_COMM_WORLD , ierror)
 
	! check
	print*, 'Process',rank,'after SCATTER',bval(1:2)
 
	call MPI_FINALIZE ( ierror ) ! Close MPI
 
end program Groupedcalculations
gc.c
#include <stddef.h>
#include <mpi.h>
 
// Grouped Calculs program
 
int main(int argc, char** argv) 
{
	MPI_Init(NULL, NULL);
	int nb_mpi_processes;
	MPI_Comm_size(MPI_COMM_WORLD, &nb_mpi_processes);
	int rank;
	MPI_Comm_rank(MPI_COMM_WORLD, &rank);
 
	double val,sum_val,mul_val,max_val,min_val;
	val = (rank + 1)*1.0;
	double aval[8];
	double bval[2];
	double cval[4];
 
	MPI_Allreduce ( &val , &sum_val , 1 , MPI_DOUBLE , MPI_SUM , MPI_COMM_WORLD );
	MPI_Allreduce ( &val , &mul_val , 1 , MPI_DOUBLE , MPI_PROD , MPI_COMM_WORLD );
	MPI_Allreduce ( &val , &max_val , 1 , MPI_DOUBLE , MPI_MAX , MPI_COMM_WORLD );
	MPI_Allreduce ( &val , &min_val , 1 , MPI_DOUBLE , MPI_MIN , MPI_COMM_WORLD );
 
	// check
	printf("Process %d I have the values %lf %lf %lf %lf %lf\n",rank,val,sum_val,mul_val,max_val,min_val);
 
	// OTHERS
	val = 0.0;
	if(rank==0) {val = 7777.0;}
	MPI_Bcast( &val , 1 , MPI_DOUBLE , 0 , MPI_COMM_WORLD);
 
	// check
	printf("Process %d after BCAST %lf\n",rank,val);
 
	int n;
	if(rank==3)
	{
		for(n=0;n<8;++n)
			aval[n] = n*10.0;
	}
	MPI_Scatter( &aval , 2 , MPI_DOUBLE , &bval , 2 , MPI_DOUBLE , 3 , MPI_COMM_WORLD);
 
	// check
	printf("Process %d after SCATTER %lf %lf\n",rank,bval[0],bval[1]);
 
	MPI_Finalize(); // Close MPI
 
	return 0;
}