Angus,
Thanks for the quick response. I am using the trilinos solvers and have
tried several different interative solvers from trilinos (GMRES, BiCGStab,
PCG), with no success.
There should be no dependence on scipy 0.7.0 ...the import rbf line can be
commented out (left over from the script I was originally trying to run).
Andy
Andrew Reeve
Associate Prof.
Dept. of Earth Sciences
University of Maine
207-581-2353
On Wed, 4 Feb 2009, Angus Hendrick wrote:
Andrew,
The pysparse solver has given me convergence problems when I used
heterogeneous diffusion coefficients in simple steady-state diffusion
problem. I have found that the Trilinos solvers overcome these problems and
deliver stable results. I haven't upgraded to scipy 0.7.0 yet so I can't
run your code on my machine to check...
Best Regards,
Angus Hendrick
On Wed, Feb 4, 2009 at 10:09 AM, A.S.Reeve <asre...@maineedu> wrote:
Daniel and Jonathan,
I'm having some difficulty getting fipy to converge for a fairly
simple problem when I include a modest amount of heterogeneity.
I've
simplified things down to a transient diffusion equation with a
source
term across selected cells along the 'top' of the model, and
type 1
boundary conditions elsewhere across the top of the model.
I've tried doing this on a couple of different grids generated
by
gmsh. One was created by writing a script to great the geometry
file
(both points and line segments, merging the files from my script
into
gmsh, then defining plane surfaces in gmsh and creating the
grid. As
I'd had problem making proper grids before, I thought this might
be
the problem and remade a simpler grid just from point data. Each
grid
has a separate file associated with it used to define different
regions within the model. Both sets of files are attached.
When I run a model with no heterogeneity, the results look
half-way
reasonable, but when I add a modest amount of heterogeneity
(based on
the zones), the model blows up and doesn't converge. I was able
to get
something to run many months ago (or so I thought), but now am
trying
to redo these models to address reviewer comments and things are
not
working out...
I'd assume FiPy should be able to handle heterogeneity. Does
this have
something to do with using a gmsh grid (should I always use
rectangular grids when using fipy)?
My script and supporting files are attached if you have time to
look
at then to see if this is my stupidity or a problem with FiPy. I
think
there are a few things in the file that are holdovers from the
case I
was initially trying to solve (ie sweeping instead of solving,
importing rbf), but I don't think they are impacting the
results. Heterogeneity is assigned in lines 55 to 57 of the
attached script.
I'm using very recent versions of fipy(2982)
Andy
Andrew Reeve
Associate Prof.
Dept. of Earth Sciences
University of Maine
207-581-2353
