[petsc-users] PetscFEIntegrateBdResidual_Basic

[David Fuentes]

Thanks for the quick reply. Indeed it does work like this. I have added a
location dependence on the boundary to differentiate the two. However, when
my mesh moves then the BC will be applied incorrectly.

*//  PetscFEIntegrateBdResidual_Basic DMPlexComputeBdResidual_Internal*

*static* *void** f0_bd_u(PetscInt dim, PetscInt Nf, PetscInt NfAux,*

                    *const** PetscInt uOff[], **const** PetscInt uOff_x[], *
*const** PetscScalar u[], **const** PetscScalar u_t[], **const**
PetscScalar u_x[],*

                    *const** PetscInt aOff[], **const** PetscInt aOff_x[], *
*const** PetscScalar a[], **const** PetscScalar a_t[], **const**
PetscScalar a_x[],*

*                    PetscReal t, **const** PetscReal x[], **const**
PetscReal n[], PetscInt numConstants, **const** PetscScalar constants[],
PetscScalar f0[])*

*{ *

*  PetscInt d;*

  *double** radius = **0.0**;*

  *const* *double**  zthresh = (**3.** - **4.5**/**2.**)***.01**; **// [m]*

  *for** (d = **0**; d < **2**; ++d) radius += x[d]*x[d];*

*  radius = sqrt(radius); *

  *if** ( radius > **.001**/**2.**  ) *

*    {f0[**0**] =  constants[**2**] * u[**0**];}*

  *else*

*    {*

*     f0[**0**] = -constants[**3**]       ; *

*    }*

*} *


On Mon, Nov 20, 2017 at 11:02 AM, Matthew Knepley <knepley at gmail.com> wrote:

> On Mon, Nov 20, 2017 at 11:46 AM, David Fuentes <fuentesdt at gmail.com>
> wrote:
>
>> *Is there a way to pass the boundary set id to the function pointers for
>> the residual evaluation on the boundary ?*
>>
>> *https://bitbucket.org/petsc/petsc/src/d89bd21cf2b5366df29efb6006298d2bc22fb509/src/dm/dt/interface/dtfe.c?at=master&fileviewer=file-view-default#dtfe.c-4245
>> <https://bitbucket.org/petsc/petsc/src/d89bd21cf2b5366df29efb6006298d2bc22fb509/src/dm/dt/interface/dtfe.c?at=master&fileviewer=file-view-default#dtfe.c-4245>*
>>
>> *I want to pass the boundary condition/constraint ID (ids):
>> PetscErrorCode PetscDSAddBoundary(PetscDS ds, DMBoundaryConditionType type,
>> const char name[], const char labelname[], PetscInt field, PetscInt
>> numcomps, const PetscInt *comps, void (*bcFunc)(void), PetscInt numids,
>> const PetscInt *ids, void *ctx)*
>>
>> *to the functions for the residual evaluation on the boundary.*
>>
>>
>> *For example, I have two side sets in an exodus file. I want to implement
>> Neumann boundary conditions on side set = 2 and Mixed/Cauchy BC on side set
>> = 3. Or similarly use different*
>>
>> *gmsh BC tags for Neumann/Mixed BC.*
>>
> I am not completely against this, but let me respond with my rationale
> first. What I thought you would do, is call AddBoundary() twice. Once with
> the
> Neumann function and value 2, and once with the Cauchy function and value
> 3. Does that not work in your situation?
>
> Also, I am refectoring this right now because a DS object can only take a
> single boundary integral point function (which is a pain for inhomogeneous
> Neumann),
> so I welcome input.
>
>   Thanks,
>
>     Matt
>
> --
> What most experimenters take for granted before they begin their
> experiments is infinitely more interesting than any results to which their
> experiments lead.
> -- Norbert Wiener
>
> https://www.cse.buffalo.edu/~knepley/ <http://www.caam.rice.edu/~mk51/>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20171120/49180319/attachment.html>