dolfin team mailing list archive

[Johan Hake <johan.hake@xxxxxxxxx>]

On Monday February 21 2011 08:18:18 Garth N. Wells wrote:
> On 17/02/11 21:28, Johan Hake wrote:
> > Hello!
> > 
> > I have a not so large 3D mesh of some 50K vertices, generated from some
> > geometry (not UnitCube).
> > 
> > When I set
> > 
> >   parameters.num_threads = 2
> > 
> > and try to assemble I just get:
> >   Coloring mesh.
> > 
> > and then it seems it wont find a solution... I had to break it because it
> > nearly hang the computer for some 5 min.
> > 
> > Have anyone experience the same? Is there any way to controll the
> > coloring?
> 
> It's had minimal testing, so issues can be expected. Can you post your
> solver? 50k vertices is not very big, so I would expect it to be pretty
> fast.

Yes I would expect that too. I have used the coloring on other meshes with 
success.

The mesh can be downloaded from here:

  <http://folk.uio.no/hake/trouble.xml.gz>

To reproduce the trouble just run:

  from dolfin import *
  mesh = Mesh('trouble.xml.gz')
  V = FunctionSpace(mesh, "CG", 1) 
  assemble(Function(V)*dx)
  parameters.num_threads = 2
  assemble(Function(V)*dx)

The mesh has two distinct domains, but that shouldnto be causing the trouble, 
as other I have successfully colored other such meshes. I guess it can be the 
particular mesh that causes coloring to stall. It is generated using tetgen. 

At the end of the day I have to wait untill we support subdomains in the 
OpenMPAssembler as I am heavily using these...

Johan


> Garth
> 
> > Johan
> > 
> > _______________________________________________
> > Mailing list: https://launchpad.net/~dolfin
> > Post to     : dolfin@xxxxxxxxxxxxxxxxxxx
> > Unsubscribe : https://launchpad.net/~dolfin
> > More help   : https://help.launchpad.net/ListHelp
> 
> _______________________________________________
> Mailing list: https://launchpad.net/~dolfin
> Post to     : dolfin@xxxxxxxxxxxxxxxxxxx
> Unsubscribe : https://launchpad.net/~dolfin
> More help   : https://help.launchpad.net/ListHelp