[petsc-users] ill-conditioned problems in PETSc

[Barry Smith]

   Also if it the condition number is, say, larger than 10^10 you likely would benefit from using quad precision for the calculations.  http://www.mcs.anl.gov/petsc/documentation/faq.html#precision

   You will not be able to use the external solvers with those mode but since it is 1d likely running sequentially will be fine.

    Barry


On Jun 27, 2012, at 9:46 AM, Matthew Knepley wrote:

> On Wed, Jun 27, 2012 at 7:55 AM, w_ang_temp <w_ang_temp at 163.com> wrote:
> Hello,
> 
>     I want to deal with the ill-conditioned problems of Terzaghi's one-dimensional consolidation
> 
> finite element equations in geotechnical engineering. So is there special support on ill-conditioned
> 
> problems using ksp in PETSc.
> 
> 
> Use a direct solver, like built-in LU,  or in parallel, MUMPS (--download-mumps).
> 
>   Matt
>  
>     Thanks.
> 
>                                                      Jim
> 
> 
> 
> 
> 
> 
> -- 
> What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead.
> -- Norbert Wiener