[Nek5000-users] low order interpolation

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

Hi Alessandro,

Ok. But, I was not talking about your matlab routines, but rather I was
talking about your nek5000 postprocessing mode. I guess they are correct,
since you got good results with Tecplot.

But anyway, the bottom line is, nek5000 uses spectral interpolation
routine, so even the higher order polynomials are orthogonal, so it is
unlikely that you will have Runge's phenomenon.

Also, I myself use hpts routines for interpolating a turbulent field

Best Regards,
Tanmoy

On Fri, Nov 20, 2015 at 10:41 AM, <nek5000-users at lists.mcs.anl.gov> wrote:

> Hi Tanmoy
>
> thanks for the quick answer, unfortunately I didn't commit this kinds of
> errors. I have already used my matlab routine for other cases and it worked
> well, so I'm pretty sure that there isn't errors. The only differences is
> that I'm using this routine to interpolate the hpts.in points on more
> complex grid and on a turbulent field. It seams that I have the Runge's
> phenomenon. Is this possible with the hpts routine?
>
> Sincerely
> Alessandro
>
>
>
>
>
> 2015-11-20 17:29 GMT+01:00 <nek5000-users at lists.mcs.anl.gov>:
>
>> Hi Alessandro,
>>
>> I use exactly the same procedure for my case. Just wondering, by any
>> chance, are there any points in hpts.in which are outside bounds of the
>> original domain, or you may resize the domain in userdat(), while
>> postprocessing in nek5000.
>>
>> Best Regards,
>> Tanmoy
>>
>> On Fri, Nov 20, 2015 at 6:46 AM, <nek5000-users at lists.mcs.anl.gov> wrote:
>>
>>> Dear neks
>>>
>>> I don't know how Nek5000 performs the interpolation with hpts() routine
>>> but I have some problem when I use this last. Using Matlab I built an
>>> hpts.in file that contains the points of a structured and not constant
>>> mesh, then using Nek in postprocessing  mode I evaluate the values of
>>> velocity an pressure in this points. When I reshape the hpts.out in order
>>> to visualize my domain, there are many zones that have no-sense values!. I
>>> performed the same interpolation in tecplot and it works fine.
>>>
>>> my question is: there's any way to perform a first order interpolation
>>> in Nek5000?
>>>
>>> Sincerely
>>> Alessandro
>>>
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>>>
>>>
>>
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