[Pw_forum] bug in mm_dispersion.f90

[Daniel Forrer]

Dear Paolo,

2009/9/29 Paolo Giannozzi <giannozz at democritos.it>

>
> On Sep 29, 2009, at 17:12 , Javier Fuhr wrote:
>
>  The parallelization is done to all processes (nproc), and
>> if I understand correctly the sum should be performed
>> over all processes. Looking better at the different
>> parallelizations, I think the correct way is to replace,
>> in mm_dispersion.f90, intra_pool_comm by world_comm
>>
>
> I think you are (almost) right. "image" parallelization, useful
> for NEB calculations, implies different atomic positions on
> different groups of processors. So the correct communicator
> is "intra_image_comm", containing nproc_image processors.
> Attached the (hopefully) correct Modules/mm_dispersion.f90.
> Thank you for reporting this bug and its (quasi-)fix
>

i'm not expert in parallelization, but it seems to me that the processor
index "mpime" should be replaced by "me_image" if we use the
"intra_image_comm" communicator.
Is it correct?

daniel

-- 
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 Daniel Forrer
 Dipartimento di Scienze Chimiche
 Università degli Studi di Padova
 V. Marzolo 1, Padova

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