Jonas,
The section 5.1.6 in MPI 4.0 should give you a better idea about the
differences between size, extent and true extent. There are also few
examples in Section 5.1.14 on how to manipulate the datatype using extent.
I think you should find Examples 5.13 to 5.16 of particular interest.
Best,
Hi George,
thanks, I'm starting to understand this now.
Still not quite intuitive that "Type_create_resized" allows me to reset
the extent but not the size (just from a naming perspective).
The man page is talking about extent, upper and lower bounds, but the
upper bound cannot be specified:
You are confusing the size and extent of the datatype. The size (aka the
physical number of bytes described by the memory layout) would be
m*nloc*sizeof(type), while the extent will be related to where you expect
the second element of the same type to start. If you do resize, you will
incorporate t
Dear Gilles,
thanks, the resizing fixes the issue, it seems. It is not really
intuitive, though, because the actual extent of the data type is
m*nloc*sizeof(int) and I have to make MPI believe that it is
nloc*sizeof(int). And indeed, this seems to be not OpenMPI-specific,
sorry for that.
Be
Jonas,
In case I misunderstood your question and you want to print
v_glob on P0: 9x2
0 9
1 10
2 11
3 12
4 13
5 14
6 15
7 16
8 17
then you have to fix the print invocation
// note: print an additional column to show the displacement error we get:
if (!rank) print("v_glob", rank, n, m,
Jonas,
Assuming v_glob is what you expect, you will need to
`MPI_Type_create_resized_type()` the received type so the block received
from process 1 will be placed at the right position (v_glob[3][1] => upper
bound = ((4*3+1) * sizeof(int))
Cheers,
Gilles
On Thu, Dec 16, 2021 at 6:33 PM Jonas Th
Dear OpenMPI community,
Here's a little puzzle for the Christmas holidays (although I would
really appreciate a quick solution!).
I'm stuck with the following relatively basic problem: given a local
nloc x m matrix X_p in column-major ordering on each MPI process p,
perform a single MPI_Gath
