Yea, I did not get all the code you need. Here is an example of making
crddm. I'm not sure if this is all best practices (Matt?)
/* create coordinate DM */
ierr = DMClone(dm, &crddm);CHKERRV(ierr);
ierr = PetscFECreateDefault(PETSC_COMM_SELF, dim, dim, PETSC_FALSE, "",
PETSC_DECIDE, &fe);CHKERRV(ierr);
// ierr = PetscFECreateLagrange(PETSC_COMM_SELF, dim, dim, PETSC_FALSE,
"", PETSC_DECIDE, &fe);CHKERRQ(ierr);
ierr = PetscFESetFromOptions(fe);CHKERRV(ierr);
ierr = DMSetField(crddm, field, NULL, (PetscObject)fe);CHKERRV(ierr);
ierr = DMCreateDS(crddm);CHKERRV(ierr);
ierr = PetscFEDestroy(&fe);CHKERRV(ierr);
On Sat, Jul 25, 2020 at 7:40 AM Stefano Zampini <stefano.zamp...@gmail.com>
wrote:
> Mark
>
> This will only work if you have a vector space for the function
>
>
> On Jul 25, 2020, at 1:13 PM, Mark Adams <mfad...@lbl.gov> wrote:
>
> I get all the coordinates with this method:
>
> static PetscErrorCode crd_func(PetscInt dim, PetscReal time, const
> PetscReal x[], PetscInt Nf_dummy, PetscScalar *u, void *actx)
> {
> int i;
> PetscFunctionBeginUser;
> for (i = 0; i < dim; ++i) u[i] = x[i];
> PetscFunctionReturn(0);
> }
>
> PetscErrorCode (*initu[1])(PetscInt, PetscReal, const PetscReal [],
> PetscInt, PetscScalar [], void *);
> /* project coordinates to vertices */
> ierr = DMCreateGlobalVector(crddm, &crd_vec);CHKERRV(ierr);
> initu[0] = crd_func;
> ierr = DMProjectFunction(crddm, 0.0, initu, NULL, INSERT_ALL_VALUES,
> crd_vec);CHKERRV(ierr);
> ierr = VecViewFromOptions(crd_vec, NULL, "-coord_view");CHKERRV(ierr);
> /* iterate over mesh data and get indices */
> ierr = VecGetArrayRead(crd_vec,&xx);CHKERRV(ierr);
> ierr = VecGetLocalSize(rho,&N);CHKERRV(ierr);
> /* access grid data here */
> for (p=0;p<N;p++) {
> for (i=0;i<dim;i++) ..... = xx[p*dim+i];
> PetscPrintf(PETSC_COMM_SELF,"xx = (%g, %g)\n", xx[p*dim+0],
> xx[p*dim+1]);
> }
> ierr = VecRestoreArrayRead(crd_vec,&xx);CHKERRV(ierr);
> ierr = VecDestroy(&crd_vec);CHKERRV(ierr);
>
> On Sat, Jul 25, 2020 at 4:10 AM Swarnava Ghosh <swarnav...@gmail.com>
> wrote:
>
>> Dear Petsc users,
>>
>> I had a trivial question about DMPlex. Suppose I have a 3D mesh of
>> tetrahedrons. I want to find out the 3D coordinates of the vertices of a
>> particular cell. What would be the function to do this?
>>
>> Thank you,
>> SG
>>
>
>
