Re: [Getfem-users] Laplacian with Q

Dear Dr. Yves,

Thank you so much for your answer and your time.

I try with "MESH_NOISED = 1;"

For exemple :

for "NX = 127; Number of dof : 16384" : I found the error_H1 = 1.239379991943454e-05

for "NX = 255; Number of dof : 65536" : I found the error_H1 =3.083252284962158e-06

Order = Log2(1.239379991943454e-05/3.083252284962158e-06)=2.0071.

Maybe we will have the superconvergence phenomena in the both cases.

Dear Thomas,

Thank you so much for your answer and your time.

For me I work with C++, I don't use any interfaces, because I need to do some modifications later. The functions used for computation of error are getfem::asm_L2_norm and getfem::asm_H1_norm.

Best regards.

2016-02-16 9:36 GMT+00:00 Thomas Linse <address@hidden>:

How did you calculate the L2 and H1 norms? I found "correct" convergence for a similar 1D problem when calculating the norms "by hand" (using Gauss integration), whereas the norms calculated using "gf_compute" from the scilab interface showed a larger convergence rate.

Maybe "gf_compute" (which calls getfem::asm_L2_norm or dasm_H1_norm) does not use the necessary order of integration?

Kind regards,

Thomas
On 16.02.2016 09:59, Yves Renard wrote:
Dear Yassine,

Superconvergence phenomena are quite common when a structured mesh is used. If you use the option "MESH_NOISED", this should (unfortunately !) disapear.

Best Regards,

Yves.

Le 15/02/2016 15:01, Yassine ZAIM a écrit :
Hi,

I want to ask you if someone has already solved the laplacian problem that exists in the tests directory with the Q_1 element in 2 dimension. Because I find the order of convergence equal to "2" for the L2 and H1 norme. what is not normal.

Best regards.

Bonjour,

S.v.p j'aimerais savoir si quelqu'un de vous a déjà testé le problème de laplacian qui exist dans la répertoire des tests avec l'élément Q_1 en dimension 2. J'ai testé ça et je trouve le même ordre pour les deux norme L2 et H1 (Ordre(L2) = Ordre(H1) = 2). Ce qui contredit la théorie.

Merci d'avance pour vos réponse.

Cordialement.

--

ZAIM Yassine
PhD Student in Applied Mathematics
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ZAIM Yassine

PhD Student in Applied Mathematics

From:	Yassine ZAIM
Subject:	Re: [Getfem-users] Laplacian with Q_1 élément.
Date:	Tue, 16 Feb 2016 10:05:02 +0000

Re: [Getfem-users] Laplacian with Q_1 élément.