[mpich-discuss] Can I choose between MPI_WIN_UNIFIED and MPI_WIN_SEPARATE ?

[Ronny Brendel]

Hey,

Can I choose between the two memory models, or is this provided by the
mpi implementation or underlying hardware?

If I can choose: How can I?
If I cannot choose: Why is that?


I tried using MPI_Win_set_attr to set it, but Mpich throws an error
that the key is invalid.

(I am using mpich 3.0.4)

Reading the standard I couldn't find out wether this is supposed to be
choosable by the user. I just assumed it is. Because, if I don't query
MPI_WIN_MODEL, there is a chance my program works on one but not on
the other.
So I have a correct program depending on which model there is and the
code looks exactly the same. Which is behavior I would not expect.

I hope you can help,
cheers,
Ronny