Hello David,

Thanks for pointing out vext.vtk.  I agree that it should make vtk accessible in a virtualenv, or so I've read. I have installed it using pip and still get the same error.  My guess is I need to do more to set things up. 

At the moment, learning gmsh doesn't sound so bad.  I will probably do that but if someone else has had any success using this please let me know.

Cheers, Francis


------------------
Francis Poulin                    
Associate Professor
Department of Applied Mathematics
University of Waterloo

email:           fpoulin@uwaterloo.ca
Web:            https://uwaterloo.ca/poulin-research-group/
Telephone:  +1 519 888 4567 x32637


From: firedrake-bounces@imperial.ac.uk [firedrake-bounces@imperial.ac.uk] on behalf of David Ham [David.Ham@imperial.ac.uk]
Sent: Monday, March 20, 2017 5:56 AM
To: firedrake; G. D. McBain
Subject: Re: [firedrake] circles in firedrake?

Hi Francis,

There appears to be something called vext.vtk which claims to make system vtk accessible from inside a virtualenv. There is also this email:
http://vtk.1045678.n5.nabble.com/Re-VTK-in-virtualenv-td5716725.html

I have to confess that I have not really tried either.

Regards,

David

On Mon, 20 Mar 2017 at 01:40 Francis Poulin <fpoulin@uwaterloo.ca> wrote:

Thanks for suggesting PyGmsh!  I bumped into it a while ago but never really figured it out.  Now I'm keen since it should help building and modifying meshes more easily.

I installed pygmsh easily using the instructions on the website.  It imports correctly.   There is even an example that builds a circle, I think.

When I try running this, as well as other examples, I get an error because no module named vtk is found.  See below. I get this comes from meshio?

Traceback (most recent call last):
  File "circle.py", line 24, in <module>
    meshio.write('circle.vtu', *out)
  File "/home/fpoulin/software/firedrake/local/lib/python2.7/site-packages/meshio/__init__.py", line 187, in write
    field_data=field_data
  File "/home/fpoulin/software/firedrake/local/lib/python2.7/site-packages/meshio/vtk_io.py", line 204, in write
    import vtk
ImportError: No module named vtk

When I do a pip install it tells me that it is already installed and up to date.


(firedrake) fpoulin@fpoulin-Gazelle:~/software/pygmsh/test/examples$ pip install -U meshio
Requirement already up-to-date: meshio in /home/fpoulin/software/firedrake/lib/python2.7/site-packages
Requirement already up-to-date: pipdated in /home/fpoulin/software/firedrake/lib/python2.7/site-packages (from meshio)
Requirement already up-to-date: numpy in /home/fpoulin/software/firedrake/lib/python2.7/site-packages (from meshio)
Requirement already up-to-date: requests in /home/fpoulin/software/firedrake/lib/python2.7/site-packages (from pipdated->meshio)
Requirement already up-to-date: appdirs in /home/fpoulin/software/firedrake/lib/python2.7/site-packages (from pipdated->meshio)

I realize this isn't necessarily a firedrake question but if anyone had an idea on how to get this working I would be keen to try it.


Cheers, Francis
------------------
Francis Poulin                    
Associate Professor
Department of Applied Mathematics
University of Waterloo

email:           fpoulin@uwaterloo.ca
Web:            https://uwaterloo.ca/poulin-research-group/
Telephone:  +1 519 888 4567 x32637


From: firedrake-bounces@imperial.ac.uk [firedrake-bounces@imperial.ac.uk] on behalf of G. D. McBain [gdmcbain@protonmail.com]
Sent: Sunday, March 19, 2017 6:16 PM

To: firedrake@imperial.ac.uk
Subject: Re: [firedrake] circles in firedrake?
I would expect a user to run gmsh separately (at the command line or through the GUI), rather than from within the Python script.  I don't think it's possible to interact with gmsh from Python nowadays without jumping through considerable hoops.

Have you tried the (free third-party) PyGmsh?  It generates .geo code from Python.  From there one calls Gmsh using Python subprocess and reads in the resulting .msh.  I've found it handy.

--
Dr David Ham
Department of Mathematics
Imperial College London