[Q-e-developers] Fwd: vdw-d failing test (./check-pw.x.j)

[Lorenzo Paulatto]

If the compiler bug is what I think it is.. you just have to use an 
auxiliary variable inside the REDUCE clause of OMP pragma instructions, 
instead of directly using the function result (i.e. the variable named 
like the function, or specified by RESULT)

cheers


On 11/03/2014 08:42 AM, Paolo Giannozzi wrote:
> On Sat, 2014-11-01 at 22:36 +0100, Lorenzo Paulatto wrote:
>
>> I did not follow the discussion
> nor did I, so can somebody please make a summary:
> - was the error already present in v. 5.1, or is it new?
> - has the place where the error occurs been found?
> - if so, is there a workaround?
>
> Paolo
>> , but I can confirm that doing openmp operation on function results
>> with intel compiler (2013 and 2014, afaik) results in all kind of
>> eisenbugs.
>>
>> cheers
>>
>>
>>
>> On 11/01/2014 01:14 PM, Filippo Spiga wrote:
>>
>>> FYI Gabriele's email bounced back, here below his message!
>>>
>>>
>>> F
>>>
>>>> Begin forwarded message:
>>>>
>>>> From: Gabriele Sclauzero <gurlomail at gmail.com>
>>>>
>>>> Subject: Re: [Q-e-developers] vdw-d failing test (./check-pw.x.j)
>>>>
>>>> Date: October 31, 2014 at 7:13:37 PM GMT
>>>>
>>>> Cc: General discussion list for Quantum ESPRESSO developers
>>>> <q-e-developers at qe-forge.org>
>>>>
>>>> To: spiga.filippo at gmail.com
>>>>
>>>>
>>>> Dear Filippo,
>>>>
>>>>
>>>>      Indeed, that commit was intended to fix a problem of OpenMP
>>>> parallelization in the calculation of forces with Grimme’s
>>>> dispersion (mm_dispersion.f90 module). The problem shows up with
>>>> some Intel compilers, but it doesn’t with the GNU ones (so, it
>>>> might be a bug of the Intel compiler, perhaps). If you look inside
>>>> vdw-d.out and you find that the output stops just before printing
>>>> out the forces, it is likely the same problem that I have met.
>>>> The workaround consists in doing the reduction on an auxiliary
>>>> array, aux(:), instead of doing it directly on force_london(:,:).
>>>> The latter is an array with two dimensions, so I think this
>>>> confuses the OpenMP compilation part (for Intel, at least).
>>>> Anyway, the fix seems to do the job without sacrificing
>>>> performance.
>>>>
>>>>
>>>> Ciao,
>>>>
>>>>
>>>> Gabriele
>>> --
>>> Mr. Filippo SPIGA, M.Sc.
>>> http://filippospiga.info ~ skype: filippo.spiga
>>>
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>> -- 
>> Dr. Lorenzo Paulatto
>> IdR @ IMPMC -- CNRS & Université Paris 6
>> +33 (0)1 44 275 084 / skype: paulatz
>> http://www-int.impmc.upmc.fr/~paulatto/
>> 23-24/4é16 Boîte courrier 115, 4 place Jussieu 75252 Paris Cédex 05
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-- 
Dr. Lorenzo Paulatto
IdR @ IMPMC -- CNRS & Université Paris 6
+33 (0)1 44 275 084 / skype: paulatz
http://www.impmc.upmc.fr/~paulatto/
23-24/4é16 Boîte courrier 115, 4 place Jussieu 75252 Paris Cédex 05