[petsc-dev] DMPlexComputeCellGeometryFVM from fortran

[Matthew Knepley]

On Thu, Mar 20, 2014 at 9:04 PM, Adrian Croucher
<a.croucher at auckland.ac.nz>wrote:

> hi,
>
>  They need to be F90 pointers and they need to be associated with an
>> allocated array. Take
>> a look at how I do it for the arguments to DMPlexCreateSection() in DMPlex
>> ex1f90.F
>>
> Thanks, I tried that and it nearly works... it gives the correct volumes,
> but it gives centroids all zero, which isn't right. My amended code is
> below.
>
> If I debug into DMPlexComputeGeometryFVM_3D_Internal() using gdb, and try
> 'p *centroid', it says 'Cannot access memory at address 0x0', which looks
> unhealthy.
>
> There is something a bit weird going on, because if I don't initialize the
> centroid and normal arrays, or even if I initialize them in the main code
> rather than in the variable declaration, I get a segfault in
> DMPlexComputeGeometryFVM_3D_Internal().
>
> Guess I'm still doing something subtly wrong here?


The interface needed to be declared. I pushed the fix, and your example to
PETSc (ex3f90).

  Thanks,

      Matt


> - Adrian
>
> --
> program main
>
> ! setting up 3-D DMPlex using DMPlexCreateFromDAG(), DMPlexInterpolate()
> and
> ! DMPlexComputeCellGeometryFVM()
>
>   implicit none
>
> #include <finclude/petsc.h90>
>
>   DM :: dm, dmi
>   PetscInt, parameter :: dim = 3
>
>   PetscInt :: depth = 1
>   PetscErrorCode :: ierr
>   PetscInt, allocatable :: numPoints(:)
>   PetscInt, allocatable :: coneSize(:)
>   PetscInt, allocatable :: cones(:)
>   PetscInt, allocatable :: coneOrientations(:)
>   PetscScalar, allocatable :: vertexCoords(:)
>   PetscReal ::  vol = 0.
>   PetscReal, target, dimension(dim)  :: centroid = 0., normal = 0.
>   PetscReal, pointer :: pcentroid(:), pnormal(:)
>
>   PetscInt :: i
>
>   numPoints = [12, 2]
>   coneSize  = [8, 8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
>   cones = [2,5,4,3,6,7,8,9,  3,4,11,10,7,12,13,8]
>   coneOrientations = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
>   vertexCoords = [ &
>        -0.5,0.0,0.0, 0.0,0.0,0.0, 0.0,1.0,0.0, -0.5,1.0,0.0, &
>        -0.5,0.0,1.0, 0.0,0.0,1.0, 0.0,1.0,1.0, -0.5,1.0,1.0, &
>         0.5,0.0,0.0, 0.5,1.0,0.0, 0.5,0.0,1.0,  0.5,1.0,1.0 ]
>   pcentroid => centroid
>   pnormal => normal
>
>
>   call PetscInitialize(PETSC_NULL_CHARACTER,ierr); CHKERRQ(ierr)
>
>   call DMPlexCreate(PETSC_COMM_WORLD, dm, ierr); CHKERRQ(ierr)
>   call PetscObjectSetName(dm, "testplex", ierr); CHKERRQ(ierr)
>   call DMPlexSetDimension(dm, dim, ierr); CHKERRQ(ierr)
>
>   call DMPlexCreateFromDAG(dm, depth, numPoints, coneSize, cones, &
>        coneOrientations, vertexCoords, ierr); CHKERRQ(ierr)
>
>   call DMPlexInterpolate(dm, dmi, ierr); CHKERRQ(ierr)
>   call DMPlexCopyCoordinates(dm, dmi, ierr); CHKERRQ(ierr)
>   call DMDestroy(dm, ierr); CHKERRQ(ierr)
>   dm = dmi
>
>   call DMView(dm, PETSC_VIEWER_STDOUT_WORLD, ierr); CHKERRQ(ierr)
>
>   do i = 0, 1
>      call DMPlexComputeCellGeometryFVM(dm, i, vol, pcentroid, pnormal,
> ierr)
>
>      CHKERRQ(ierr)
>      write(*, '(a, i2, a, f8.4, a, 3(f8.4, 1x))'), &
>           'cell: ', i, ' volume: ', vol, ' centroid: ', &
>           pcentroid(1), pcentroid(2), pcentroid(3)
>
>   end do
>
>   call DMDestroy(dm, ierr); CHKERRQ(ierr)
>   call PetscFinalize(ierr); CHKERRQ(ierr)
>   deallocate(numPoints, coneSize, cones, coneOrientations, vertexCoords)
>
> end program main
>
> --
> Dr Adrian Croucher
> Department of Engineering Science
> University of Auckland
> New Zealand
> tel 64-9-373-7599 ext 84611
>
>


-- 
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
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