[Dune] Question about parallelization

[Aleksejs Fomins]

Dear Dune,

I use the collective communication class and its operations gather and 
min to communicate data.

1) If I use the gather, min operations, do I have to run them in all 
processes?
Even if I require the resulting data only in the master process?

2) If I need to communicate 1 double from all processes to the master 
process,
do I just make a double array of size 1 in all processes and use a 
gather operation on it?

3) Do I understand correctly, that
in the gather operation, arrays sent by each process have to be the same 
in size,
and furthermore, every entry of the array which is templated to T has to 
be the same size as well?

Have a nice day,

-- 
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Aleksey Fomin
Junior Research Scientist
Computational Accelerator Group
Paul Scherrer Institut
5232 Villigen PSI
Switzerland
Phone: +41 (0)56 310 5019
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