[petsc-users] Is there efficeint method for matrix with one extremely small eigen value?

[Jed Brown]

2011/4/6 Gong Ding <gdiso at ustc.edu>

> Ok, I will investigate matrix null space problem.
> The matrix comes from nonlinear problem, I wonder if I need to calculate
> the eigenvector each time.
>

Possibly, but it is more likely that the null space is something simple like
a constant.


>
> Several months ago, some one committed DGMRES implementation, which also
> dropped smallest eigen value.
> It it possible to use (slightly modified) DGMRES as flexable tool for
> sigular problem?
>

I'm not familiar with DGMRES.
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