[Nek5000-users] Output data format and VisIt issue

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

Hi,
indeed, VisIt even in the latest version does not read the 8-byte format 
properly. The problem, in fact, is mainly related to the computations of 
the limits (at least in 2D), and by just setting these manually (in 
Controls/View) it can be corrected. The data appears to be read in 
without problem.

Jing has analysed the source code of the Nek reader, and fixed the 
corresponding parts; he has already sent it further to the VisIt 
developers, and hopefully the next version will read 8-byte files as well.

Regarding the restart with 4-byte files, I guess the answer is that it 
depends on the case and the requirements on accuracy you have. In my 
opinion, for stability calculations you will not only need 8-byte files, 
but also the restart from 4 files (aka proper restart). Similar 
observations we have made for high-Reynolds-number turbulence. On the 
other hand, for low-Re cases I guess there is not much of a problem.

Best regards,
Philipp


On 2015-03-15 20:16, nek5000-users at lists.mcs.anl.gov wrote:
> Dear Neks,
>
>
> Recently I've been playing with VisIt and it seems there is still
> problem reading nek5000 output data in 8-byte format. VisIt reads 4-byte
> output data successfully but not 8-byte. Is it essential to output data
> in 4-byte format if I want to use VisIt (ParaView actually can handle
> both data format well)?
>
>
> Also, in terms of continuing simulations, would 4-byte precision affect
> the restarting condition?
>
>
> Hope anyone can help. Thank you very much in advance.
>
>
> Kind regards,
>
> Tony
>
>
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