On Sep 17, 2005, at 1:28 PM, Rainer Keller wrote:
On Friday 16 September 2005 18:41, Brian Barrett wrote:
A quick question about MPI_Group_range_excl(). I notice that if
for a
given triplet, first_rank == last_rank, we error if stride is not
1. I
notice we don't have that test in MPI_Group_range_incl(). Is there a
reason that test should be there - the standard doesn't seem to imply
that stride must be 1 if first_rank == last_rank.
As said in the other mail, the standard claims, that an
MPI_Group_incl(i) /
MPI_Group_excl(i) is equivalent to an MPI_Group_range_incl /
MPI_Group_range_excl with (i,i,1) -- see p. 142 in the MPI-11
standard.
So, the test is just for correctness of the supplied data (or
against lazyness
of the app.-programmer? ,-])
But it only says that calling MPI_Goup_excl() is equivalent to
calling MPI_Group_range_excl(), with every rank i given to
MPI_Group_excl() becoming a triple (i, i, 1). It says nothing of the
behavior of the function if the triple (i, i, X) if X is not 1...
But then again, the std. is (as always) not too strict in
specifying all those
marginal cases. So, I don't feel too strong about this test.
BTW: the intel-tests failing are in MPI_Group_range_excl3_c.c, right?
correct.
Brian
--
Brian Barrett
Open MPI developer
http://www.open-mpi.org/
