[Nek5000-users] Connectivety

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

Hi Stefan,
It is clear. Thank you very much.
Antonios

On 10 dec 2010, at 11:11, nek5000-users at lists.mcs.anl.gov wrote:

> Antonois:
> 
> I understand your confusion. Let me backup a little bit.
> 
> Genmap will try to establish a unique global numbering for all element vertices. Basically, genmap tries to detect (based on the vertex coordinates) the shared vertices and will assign a global id. We compute what you call the connectivity information on the fly (during the setup phase of Nek) based on the global vertex ids read from the .map file. 
> 
> You're right the old ASCII .rea file contains the elemental connectivity but this information is no longer used (we do a formatted dummy read for these lines). The .re2 file does not contain this information anymore.
> 
> 
> hth,
> Stefan
> 
> 
> ----- Original Message -----
> From: nek5000-users at lists.mcs.anl.gov
> To: nek5000-users at lists.mcs.anl.gov
> Sent: Friday, December 10, 2010 10:10:16 AM
> Subject: Re: [Nek5000-users] Connectivety
> 
> Thank you for the responses.
> However maybe my question I was clear before. I try again: Ok, the
> connectivity information comes from the rea file when you run genmap,
> but is it computed based on the spatial coordinates given in the rea
> file, or is it just taken from the connectivity information given later,
> also in the rea file along with the boundary conditions?
> 
> What we experience is that we have a grid which is created in Matlab and
> then we write it in "rea file format" which is later read by genmap and
> reatore2 etc. This rea file, after the spatial coordinates of the
> element corners, contains a list with all the elements and their
> connectivity information.
> Here is what two lines looks like:
> 
> W 4 1  0.000000      0.000000      0.000000      0.000000      0.000000
> E 4 2  5.000000      4.000000      0.000000      0.000000      0.000000
> 
> Here I specify Wall condition for element 4 and face 1 and Element
> condition for face 2 that connects to element 5 with face 4.
> But then when I removed my connectivity info, that is having every where
> zeros in the 4th and 5th column:
> 
> W 4 1  0.000000      0.000000      0.000000      0.000000      0.000000
> E 4 2  0.000000      0.000000      0.000000      0.000000      0.000000
> 
> the case seemed to run fine, and the flow looked correct.
> Does this mean that the connectivity specified there does not matter?
> 
> Best,
> /Antonios
> 
> 
> 
> nek5000-users at lists.mcs.anl.gov wrote:
>> This is correct.
>> -Stefan
>> 
>> ----- Original Message -----
>> From: nek5000-users at lists.mcs.anl.gov
>> To: nek5000-users at lists.mcs.anl.gov
>> Sent: Thursday, December 9, 2010 6:15:02 PM
>> Subject: Re: [Nek5000-users] Connectivety
>> 
>> Hi Antonios,
>> 
>> I could be wrong but I think that the only connectivity information that 
>> Nek5000 need comes from global vertexi element numbering genereated by 
>> .map file which is in turn produced by running genmap on .rea file
>> 
>> Best,
>> Aleks
>> 
>> 
>> On Thu, 9 Dec 2010, nek5000-users at lists.mcs.anl.gov wrote:
>> 
>>> Hello Paul,
>>> I have a question about the connectivity of the elements.
>>> In the old rea file format (which we convert to the new binary with
>>> reatore2) we have listed the Element geometrical date and after that the
>>> Boundary conditions and connectivity data.
>>> My question is whether the connectivity of the elements stated there is
>>> actually used or it is somehow re-computed while the code runs based on
>>> the node coordinates. I am talking specifically about the connectivity
>>> between the elements, not the boundary conditions with the "outside world".
>>> Best regards,
>>> Antonios
>>> 
>>> -- 
>>> ---------------------------------------------------------------------------------------------
>>> Antonios Monokrousos
>>> Department of Mechanics                 email:    antonios at mech.kth.se
>>> Royal Institute of Technology (KTH)     phone:    +46 8 790 68 76
>>> Osquars Backe 18                        telefax:  +46 8 796 98 50
>>> SE-100 44 Stockholm, SWEDEN
>>> _______________________________________________
>>> Nek5000-users mailing list 
>>> Nek5000-users at lists.mcs.anl.gov
>>> https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users
>>> 
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> 
> 
> -- 
> ---------------------------------------------------------------------------------------------
> Antonios Monokrousos
> Department of Mechanics                 email:    antonios at mech.kth.se
> Royal Institute of Technology (KTH)     phone:    +46 8 790 68 76
> Osquars Backe 18                        telefax:  +46 8 796 98 50
> SE-100 44 Stockholm, SWEDEN
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