* Richard Treumann <treumann_at_[hidden]> [2008-03-03 12:01:12]:
The real concern here is:
Does the MPI implementation need to provide data conversion services between any pair of tasks in the communiator? If I have some tasks on a slow node and other tasks on a fast one we could debate whether that is heterogeneous.
I think the proposal has merit but we need to be specific that only data representation conversion for data transfer routines is involved in the meaning of "heterogeneous".
This is what I meant: that's why I talked about not specifying the correct datatype, but instead using MPI_BYTE and relying on the fact that the in-memory representation on both ranks is the same. So, my definition of 'heterogenous': not having the same in-memory data representation. Greetings, Dries
Some applications are not written with heterogenous environments in mind; They do not (always) use correct datatype descriptions when sending or receiving data, but instead treat the data as an array of bytes, relying on all datatypes having the same memory representation on both sender and receiver. Most often, this is done to avoid the added complexity of creating the correct datatypes.
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