Hi Robert,

On Friday, August 8, 2014 4:33:03 AM UTC-4, Robert Cimrman wrote:

Hi Geoff,

On 08/07/2014 10:05 PM, Geoff Wright wrote:
> Hi Robert,
>
> I'm getting pretty good results now, even on my final model which is a bit
> more complex than what I've been showing you. In addition to the points
> your mentioned, which were very helpful, I also found that running the
> 'optimize 3D' option in gmsh does give a significant improvement in
> reducing the magnitude of this error. My hypothesis is that before running
> the mesh optimizer there may be a lot of very small cells which might have
> wild gradients. The 3D optimizer I assume does some sort of
> regularization, removing the small cells. After combining all these
> effects the loss in flux at the sink is approx 1%, which is acceptable for
> my purposes.

Glad to hear that! If it's not secret, I would like to see some nice figures :)

Unfortunately the full model is proprietary right now. Once it becomes public I will try and remember to come back here and add the figures!

> Overall factors which helped:
> - increasing mesh density around the areas of interest
> - choosing the right solver

You are using pyamg, right?

Yes, I'm using pyamg as you described earlier in this thread

> - using gmsh 3D optimizer to eliminate small cells

This has to be run from the GUI, or is there a command-line switch as well? I
tried:

gmsh -3 sphere_disc_inside_sphere.geo -format mesh -optimize

Yes, I think that is equivalent to what I did in the GUI. Theres also the optimize_netgen option which I haven't experimented with.

r.

> - fixing various bugs which Robert found (thanks!)
>