Re: [Libmesh-users] infinite elements & complex fields

[Rolf M. <ro...@mi...>]

Dear Steffen,

thank you so much again for your kind help.

On Thu, Mar 24, 2005 at 06:46:39PM +0100, Steffen Petersen wrote:
 
> The problem is somehow related to laspack. When using PETSc
> everything works fine and I get reasonable results.

OK, what an irony: I had chosen laspack, because I had - wrongly -
assumed that it would be the least error-prone. Now I am using PETSc
(configuration "--enable-petsc --enable-complex --enable-mpi") and I
think it works: The spherical symmetry of the solution looks very good
in general and was perfect where I tested it (along the x-axis).

Here are some example results for the real part of the solution along
the x-axis:

    x         ex6       cos(x)/(4*pi*x)
         0    6.5665       Inf
    0.0667    0.6505    1.1910
    0.1333    0.6000    0.5915
    0.2000    0.3743    0.3900
    0.2667    0.2840    0.2879
    0.3333    0.2231    0.2256
    0.4000    0.1818    0.1832
    0.4667    0.1514    0.1523
    0.5333    0.1278    0.1285
    0.6000    0.1090    0.1095
    0.6667    0.0934    0.0938
    0.7333    0.0803    0.0806
    0.8000    0.0691    0.0693
    0.8667    0.0592    0.0594
    0.9333    0.0506    0.0507
    1.0000    0.0214    0.0430

So it seems that - away from the singularity - the accuracy of the
solution is pretty good, but it deteriorates at the node which is
shared with the infinite element (at x=1). - Is that a necessity, BTW?

Thank you once more.

Happy Easter,
Rolf