[Nek5000-users] Sharing parameters between processors

[nek5000-users at lists.mcs.anl.gov]

Indeed, common blocks only work with the local memory. The easiest way 
is, if it is only a few parameters, that you put them into the rea file 
in the unused section (say about index 120 or so). Then the values are 
immediately available on each processor.

Otherwise you have to do explicit communication. The starting point 
would be the broadcast operation, bcast(buf,len), which shares len reals 
stored on process 0 with all other processes. bcast is a wrapper to the 
standard MPI function
  call mpi_bcast (buf,len,mpi_byte,0,nekcomm,ierr)

Hope this helps,
Philipp

On 2015-11-30 23:31, nek5000-users at lists.mcs.anl.gov wrote:
> Hi Nekers,
>
> In my current simulation, I am defining an array containing parameters
> that are shared between several processors. I have tried to do this in
> the usercheck subroutine, with a COMMON statement. However, the COMMON
> statement enables saving the parameters between two successive calls of
> the usercheck by the same processor, but does not enable to share a
> variable between two processor. In other words, if I modify the variable
> a on the processor 1, the variable a on the processor 2 will not be
> modified, which is not what I want. Any idea on how to do that?
>
> Thanks for your help,
>
> Oscar Valdorez
>
>
>
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