parallel_reduce of size 0, not calling init/join

[bathmatt]

I would assume that if you call a parallel_reduce(0, functor) it would call init and then join for the result, or at least call init for the result. However, this call does nothing.

Therefore, for a reduction of an array has to do the convoluted code listed below with the if statement.

if ( particles_.migrate_count_() == 0 )
for (size_t i=0; i<n_remote_procs_; ++i)
count[i] = 0;
else
// This is the only thing that should be needed
Kokkos::parallel_reduce(particles_.migrate_count_(), counter, &count[0]);

[crtrott]

That was supposed to get fixed with a commit about 5 days ago, which should have made it into Trilinos with the last integration I believe. Is this an issue in the current Head Trilinos?

Here is the commit: 432e294

[bathmatt]

After an update, this seems to work,

[crtrott]

OK great. And its not an accident but was explicitly fixed ! ;-) Closing the issue.

[bathmatt]

Did you add a test because this was fixed previously (I reported it a long while ago) and broken since then.

[hcedwar]

Yes - unit tests were added.