Hi,
In Fortran, using uninitialised variables is undefined behaviour. In this case,
it’s being initialised to zero (either by the compiler or by virtue of being in
untouched memory), and so equivalent to MPI_COMM_WORLD in OpenMPI. Other MPI
libraries don’t have MPI_COMM_WORLD .eq. 0 and so t
On Sunday, August 21, 2016, Ben Menadue wrote:
> Hi,
>
>
>
> In Fortran, using uninitialised variables is undefined behaviour. In this
> case, it’s being initialised to zero (either by the compiler or by virtue
> of being in untouched memory), and so equivalent to MPI_COMM_WORLD in
> OpenMPI. Oth
Hi All,
My two cents, in the old days of SGI, their compiler used to
initialize declared variables, usually to zero. When users moved to a
new machine, like a Cray or SP, all hell broke loose because other
compilers don't. As a result, almost everyone now gives you a switch to
have the com
Perhaps even better, you could set an invalid default value inside the type
definition:
type, BIND(C) :: MPI_Comm
integer :: MPI_VAL = some_invalid_value
end type MPI_Comm
Otherwise, they’ll likely be “initialised” to whatever value was already at
that location in memory – which
