Re: [deal.II] Nonhomogeneous Dirichlet Boundary conditions using a Dirichlet lift

[Giulia Deolmi]

Thanks a lot!
I will have a look at it,
kind regards,
Giulia

Il giorno giovedì 9 febbraio 2017 15:19:07 UTC+1, Wolfgang Bangerth ha 
scritto:
>
>
> > as far as I have understood (but I might be wrong), the functions 
> > VectorTools::interpolate_boundary_values 
> > <
> https://www.dealii.org/8.4.0/doxygen/deal.II/namespaceVectorTools.html#af6f700f193e9d5b52e9efe55e9b872d5>
>  
>
> > MatrixTools::apply_boundary_values 
> > <
> https://www.dealii.org/8.4.0/doxygen/deal.II/namespaceMatrixTools.html#a41a069894610445f84840d712d4f891e>
>  
>
> > find the nodes where Dirichlet BC's are applied and then there impose 
> the 
> > corrensponding boundary value, after having built the system matrix and 
> > right-hand side. 
> > 
> > Another possibility would be to use a Dirichlet lift, change the weak 
> > formulation and solve for homogeneous Dirichlet boundary conditions. I 
> am 
> > wondering if someone already did this or if it somewhere implemented in 
> deal.ii 
>
> It may not look like it, but that's really what the functions do that you 
> cite 
> above. 
>
> The algorithm is a bit complicated, but take a look at lectures 21.6 and 
> 21.65 
> here: 
>http://www.math.colostate.edu/~bangerth/videos.html 
>
> Best 
>   Wolfgang 
>
> -- 
>  
> Wolfgang Bangerth  email: bang...@colostate.edu 
>  
> www: http://www.math.colostate.edu/~bangerth/ 
>
>

-- 
The deal.II project is located at http://www.dealii.org/
For mailing list/forum options, see 
https://groups.google.com/d/forum/dealii?hl=en
--- 
You received this message because you are subscribed to the Google Groups 
"deal.II User Group" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to dealii+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

Re: [deal.II] Nonhomogeneous Dirichlet Boundary conditions using a Dirichlet lift

[Wolfgang Bangerth]

as far as I have understood (but I might be wrong), the functions
VectorTools::interpolate_boundary_values

MatrixTools::apply_boundary_values

find the nodes where Dirichlet BC's are applied and then there impose the
corrensponding boundary value, after having built the system matrix and
right-hand side.

Another possibility would be to use a Dirichlet lift, change the weak
formulation and solve for homogeneous Dirichlet boundary conditions. I am
wondering if someone already did this or if it somewhere implemented in deal.ii


It may not look like it, but that's really what the functions do that you cite 
above.


The algorithm is a bit complicated, but take a look at lectures 21.6 and 21.65 
here:

  http://www.math.colostate.edu/~bangerth/videos.html

Best
 Wolfgang

--

Wolfgang Bangerth  email: bange...@colostate.edu
   www: http://www.math.colostate.edu/~bangerth/

--
The deal.II project is located at http://www.dealii.org/
For mailing list/forum options, see 
https://groups.google.com/d/forum/dealii?hl=en
--- 
You received this message because you are subscribed to the Google Groups "deal.II User Group" group.

To unsubscribe from this group and stop receiving emails from it, send an email 
to dealii+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

Re: [deal.II] Nonhomogeneous Dirichlet Boundary conditions using a Dirichlet lift

[Giulia Deolmi]

Hi Praveen,

as far as I have understood (but I might be wrong), the functions
VectorTools::interpolate_boundary_values 

MatrixTools::apply_boundary_values 

find the nodes where Dirichlet BC's are applied and then there impose the 
corrensponding boundary value, after having built the system matrix and 
right-hand side.

Another possibility would be to use a Dirichlet lift, change the weak 
formulation and solve for homogeneous Dirichlet boundary conditions. I am 
wondering if someone already did this or if it somewhere implemented in 
deal.ii

I am currently dealing with parameter dependent Dirichlet boundary 
conditions and I would like to be able to see explicitly how these 
parameters enter the system matrix and the right-hand side, writing the 
dependency in an affine way, i.e. p1 A1 + p2 A2 +...= p1 f1 + p2 f2 + 
I am currently not able to do it using the function 
MatrixTools::apply_boundary_values 

 .

Thanks for your reply!
Kind regards,
Giulia



Il giorno mercoledì 8 febbraio 2017 17:21:46 UTC+1, Praveen C ha scritto:
>
> Hello Giulia
>
> The usual way of applying Dirichlet bc in deal.II essentially does a 
> lifting approach. If 
>
> u = g on boundary
>
> then the lifting is
>
> u_{g,h}(x) = sum_(i on boundary) g(x_i) \phi_i(x)
>
> Did you want to use a different lifting ?
>
> Best
> praveen
>
> On Wed, Feb 8, 2017 at 8:38 PM, Giulia Deolmi  > wrote:
>
>> Dear deal.ii users,
>>
>> is there someone who implemented Nonhomogeneous Dirichlet Boundary 
>> conditions using a Dirichlet lift? 
>>
>> Thanks a lot in advance,
>> Kind regards,
>> Giulia
>>
>> -- 
>> The deal.II project is located at http://www.dealii.org/
>> For mailing list/forum options, see 
>> https://groups.google.com/d/forum/dealii?hl=en
>> --- 
>> You received this message because you are subscribed to the Google Groups 
>> "deal.II User Group" group.
>> To unsubscribe from this group and stop receiving emails from it, send an 
>> email to dealii+un...@googlegroups.com .
>> For more options, visit https://groups.google.com/d/optout.
>>
>
>

-- 
The deal.II project is located at http://www.dealii.org/
For mailing list/forum options, see 
https://groups.google.com/d/forum/dealii?hl=en
--- 
You received this message because you are subscribed to the Google Groups 
"deal.II User Group" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to dealii+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

Re: [deal.II] Nonhomogeneous Dirichlet Boundary conditions using a Dirichlet lift

[Praveen C]

Hello Giulia

The usual way of applying Dirichlet bc in deal.II essentially does a
lifting approach. If

u = g on boundary

then the lifting is

u_{g,h}(x) = sum_(i on boundary) g(x_i) \phi_i(x)

Did you want to use a different lifting ?

Best
praveen

On Wed, Feb 8, 2017 at 8:38 PM, Giulia Deolmi 
wrote:

> Dear deal.ii users,
>
> is there someone who implemented Nonhomogeneous Dirichlet Boundary
> conditions using a Dirichlet lift?
>
> Thanks a lot in advance,
> Kind regards,
> Giulia
>
> --
> The deal.II project is located at http://www.dealii.org/
> For mailing list/forum options, see https://groups.google.com/d/
> forum/dealii?hl=en
> ---
> You received this message because you are subscribed to the Google Groups
> "deal.II User Group" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to dealii+unsubscr...@googlegroups.com.
> For more options, visit https://groups.google.com/d/optout.
>

-- 
The deal.II project is located at http://www.dealii.org/
For mailing list/forum options, see 
https://groups.google.com/d/forum/dealii?hl=en
--- 
You received this message because you are subscribed to the Google Groups 
"deal.II User Group" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to dealii+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

[deal.II] Nonhomogeneous Dirichlet Boundary conditions using a Dirichlet lift

[Giulia Deolmi]

Dear deal.ii users,

is there someone who implemented Nonhomogeneous Dirichlet Boundary 
conditions using a Dirichlet lift? 

Thanks a lot in advance,
Kind regards,
Giulia

-- 
The deal.II project is located at http://www.dealii.org/
For mailing list/forum options, see 
https://groups.google.com/d/forum/dealii?hl=en
--- 
You received this message because you are subscribed to the Google Groups 
"deal.II User Group" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to dealii+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.