[petsc-dev] Question About Petsc ILU

[Jed Brown]

On Thu, Dec 29, 2011 at 19:30, Dave Nystrom
<Dave.Nystrom at tachyonlogic.com>wrote:

> Generally I use CG and LU from petsc.  Cholesky runs slower than LU and I
> was
> told in a previous email that it was because of the extra data movement for
> Cholesky versus LU.  I have also tried minres instead of CG and tend to get
> reduced iteration counts.  But I think minres may have an extra dot product
> and so is a little more expensive than cg.  But minres is usually cheaper
> over all because of the reduction in iterations.
>

If you are concerned about solve time for serial runs, I would either use
Cholesky from MUMPS or CHOLMOD (install suitesparse, then -pc_type cholesky
-pc_factor_mat_solver_type cholmod).
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