[petsc-users] Feature request: Origin QMR implementation.

[Jed Brown]

Ce Qin <qince168 at gmail.com> writes:

> Dear all,
>
> Now I'm solving Maxwell's equations using finite difference method. In the
> beginning, I use BCGS to solve the linear system. It works, but converges
> slowly. And other solvers do not converge. Some others told me that QMR may
> be a good choice, so I tested it using matlab, the result shows that QMR
> works well than BCGS. I found that PETSc only provide TFQMR and TCQMR, so I
> wonder that why PETSc does not implement QMR solver. 

What preconditioner were you using with MATLAB's QMR?

My recollection is that the original QMR requires splitting the
preconditioner, as with PC_SYMMETRIC, which is hard to do in general.
Other than that, I think there just wasn't much demand.  Is your system
complex symmetric?

Is QMR something you might be interested in implementing?  (It's a very
manageable task and we can advise; otherwise it's contingent on one of
us finding "free" time to write it.)
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 835 bytes
Desc: not available
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20131218/3a548140/attachment.pgp>