Comment 1 for bug 1009441

I implemented this a long time ago, but VTK/ParaView did not draw
triangular cells when using high-order triangles, which was a bit
misleading for visualisation.

Garth

On 6 June 2012 13:52, Patrick Farrell <email address hidden> wrote:
> Public bug reported:
>
> VTK supports P2 fields on triangles and tetrahedra (http://www.vtk.org/doc/nightly/html/classvtkQuadraticTriangle.html).
> However, when I dump a P2 field in Dolfin to VTK, I get a P1 representation:
>
> ----------------------------------------------------------------
> from dolfin import *
>
> mesh = UnitSquare(5, 5)
> P2 = FunctionSpace(mesh, "CG", 2)
> P1 = FunctionSpace(mesh, "CG", 1)
>
> print "P2.dim(): ", P2.dim()
> print "P1.dim(): ", P1.dim()
>
> v = Function(P2)
> v.vector()[:] = 1.0
> f = File("p2.pvd")
> f << v
>
> import os
> os.system("grep NumberOfPoints p2000000.vtu")
> ----------------------------------------------------------------
>
> The output of this script is:
> P2.dim():  121
> P1.dim():  36
> <Piece  NumberOfPoints="36" NumberOfCells="50">
>
> i.e. the VTK file produced has 36 dof, not 121.
>
> Would it be possible to make VTK output P2 functions without any
> projections to P1?
>
> ** Affects: dolfin
>     Importance: Undecided
>         Status: New
>
> --
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> Core Team, which is subscribed to DOLFIN.
> https://bugs.launchpad.net/bugs/1009441
>
> Title:
>  Writing a P2 function to VTK should use VTK's quadratic elements
>
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