discover_snd_parts warning

[amartinhuertas]

Hi @fverdugo,

we know that the current implementation of discover_snd_parts is not scalable. However, the user might not know that. While we dont have an scalable implementation I would warn the user on screen with a message. Something like:

"[PartitionedArrays.jl] Warning: Using a non-scalable implementation to discover reciprocal parts in sparse communication kernel among nearest neighbours. This might cause trouble when running the code at medium/large scales. You can avoid this using the Exchanger constructor with bla bla bla"

I guess that we can do it on the master task using the @warn macro right at the beginning of a call to discover_parts_snd.

What do you think? Any other ideas while we do not have the scalable solution?

[fverdugo]

We can add this warning no problem. It would be useful to check that we always use the scalable versions (i.e. by running our CI always with error on warning)

[amartinhuertas]

We can add this warning no problem.

Done in PR https://github.com/fverdugo/PartitionedArrays.jl/pull/42

It would be useful to check that we always use the scalable versions (i.e. by running our CI always with error on warning)

I think we cannot do that, right? I mean that we are willing to test the non-scalable version on CI as well.