[Nek5000-users] Vanishing Jacobian error description

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

One other question -

Have you sorted out how the 12 edges are numbered?


On Wed, 21 Apr 2010, nek5000-users at lists.mcs.anl.gov wrote:

>
> Michael,
>
> I looked at this for a couple of different N.
>
> nek/postx think that the geometry is messed up ---
>
>  see  www.mcs.anl.gov/~fischer/zzz.jpg
>
> That being said, it could easily be a problem w/ the midside
> node support that I added last month.   (NOTE: to see the
> geometry I had to fix something in the nek code -- normally
> when you get vanishing jacobian the code will output "xyzblah.fld01"
> with the geometry, so that you can then look at this in postx or
> visit.  For pn/pn, this was broken but is now working in the just-updated 
> repo.)
>
> Do you have a way to verify that your lofting is working?
>
> Paul
>
>
> On Wed, 21 Apr 2010, nek5000-users at lists.mcs.anl.gov wrote:
>
>> Hi,
>> 
>> Sorry, yes that was for without the curve side data. Here is the case that 
>> includes the curved side data.
>> 
>> - Michael
>> 
>> ----- Original Message -----
>> From: nek5000-users at lists.mcs.anl.gov
>> To: nek5000-users at lists.mcs.anl.gov
>> Sent: Wednesday, April 21, 2010 8:39:38 AM GMT -06:00 Guadalajara / Mexico 
>> City / Monterrey
>> Subject: Re: [Nek5000-users] Vanishing Jacobian error description
>> 
>> The case you sent runs fine.... is it w/ or w/o the curved side info? Paul 
>> On Wed, 21 Apr 2010, nek5000-users at lists.mcs.anl.gov wrote: > > > Hi Paul, 
>> > > > > Here is the rea, usr, & SIZE file I am using. I ran it again 
>> without the curved side information and it worked, so I think the problem 
>> is somewhere in the curved side section of the rea. > > > > The geometry is 
>> a square base lofted into a circle in the +z direction. The mesh was 
>> generated in gambit. I've developed a matlab code that will take a mesh 
>> created in gambit and generate the required REA formatting. I have created 
>> some basic shapes to test the matlab portion and the curved side portion, 
>> and it worked in most cases (not this one yet). I'm not sure what is going 
>> on with the curved side data in this case however. > > > > Thanks for 
>> looking at this, > > Michael > > > ----- Original Message ----- > From: 
>> nek5000-users at lists.mcs.anl.gov > To: "Nekton User List" > Sent: Tuesday, 
>> April 20, 2010 3:36:44 PM GMT -06:00 U
> S/Canada Central > Subject: Re: [Nek5000-users] Vanishing Jacobian error 
> description > > > > Michael, > > The code is trying to check to ensure that 
> the mesh is > valid. Sometimes, however, there are other causes for > the 
> problem. > > Can you send a gzip'd rea/usr file, and I can take a look > 
> later tonight. > > Paul > > > > On Tue, 20 Apr 2010, 
> nek5000-users at lists.mcs.anl.gov wrote: > >> Hi, >> >> I am running into an 
> issue with 'Vanishing Jacobian'. To help understand what the problem >> is, 
> could someone explain what is meant in the error? Specifically, what it means 
> by "Xth node" of the element. >> Also, I ran into this issue when I was 
> deforming geometries in the usr file, where one of the elements >> would 
> overlap another by mistake. However in this case I know there are no 
> overlaps. >> >> Here is a portion: >> >> 0 ERROR: Vanishing Jacobian near 
> 91th node of element 69. >> 1.40692804605498586E-002 
> -7.79619559165757245E-003 >> 0 xyz: 2.65874E-01 3.54498E-01 2.87050E+0
> 0 >> 0 xyz: 2.07855E-01 1.77249E-01 2.87050E+00 >> >> >> 0 ERROR: Vanishing 
> Jacobian near 76th node of element 70. >> 2.59472856644434001E-002 
> -2.12442422718029170E-002 >> 0 xyz: 2.11655E-01 4.23310E-01 2.62500E+00 >> 0 
> xyz: 3.54498E-01 1.77249E-01 2.87050E+00 >> >> Thanks for any help 
> deciphering this error! >> >> - Michael >> >> >> >> >> >> > 
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