dolfin team mailing list archive

[Anders Logg <logg@xxxxxxxxx>]

Hi Catherine,

This looks like an excellent candidate for a premiere post to our new
mailing list (created yesterday):

  fenics-users@xxxxxxxxxx

Could you resend it there?

--
Anders


On Mon, Aug 10, 2009 at 10:06:24PM -0500, Catherine Micek wrote:
> Hi,
>
> I am working on a 3D finite element code and would like to use
> a cylinder mesh.  Since there is no built-in cylinder mesh, I tried generating one from a the
> built-in UnitCube mesh:
>
> # Create mesh
> mesh = UnitCube(2,2,2)
>
> # Translate origin from (0.5, 0.5, 0.5) to (0.0, 0.0)
> for x in mesh.coordinates():
>         x[0] = x[0] - 0.5
>         x[1] = x[1] - 0.5
>         x[2] = 4.0*(x[2] - 0.5)
>
> # Create boundary mesh
> boundary = BoundaryMesh(mesh)
>
> # Stretch to a circle
> for x in boundary.coordinates():
>         # Circle parameters
>         theta = atan2(x[1],x[0])
>         r = 2.0
>         x[0] = r*cos(theta)
>         x[1] = r*sin(theta)
>         x[2] = x[2]
>
> # Move boundary values of mesh
> mesh.move(boundary)
>
> The mesh plots in Viper fine and looks nice, but does not work properly when I
> use it in code.  When I look at the .xml file, some identical vertices are
> numbered twice, as though they are being interpreted as different vertices.
>  I'm not sure what's causing this, although it seems to be related to the
> dimension: when I run similar code on the UnitSquare in 2D to generate a
> circle, I don't encounter this problem
>
> So my questions are these:
>
> 1. Is there a way to correct this code so that the mesh can be generated
> without repeated vertices?
> 2. I have Matlab code to generate a cylinder; is there an easy way to convert
> that to a form that can be used by fenics?
>
> Any suggestions would be greatly appreciated -- thanks!
>
> Katy
>
> ---
> Catherine (Katy) A. Micek
> Graduate Assistant, U of MN Mathematics Department
> http://www.math.umn.edu/~mice0012
>
>
>
>

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