[Trilinos-Users] MueLu: maps unique, same

[Hoemmen, Mark]

On 6/24/15, 3:19 AM, "trilinos-users-request at trilinos.org"
<trilinos-users-request at trilinos.org> wrote:
>Message: 2
>Date: Sat, 20 Jun 2015 15:07:14 -0700
>From: Jonathan Hu <jhu at sandia.gov>
>To: <trilinos-users at trilinos.org>
>Subject: Re: [Trilinos-Users] MueLu: maps unique, same
>Message-ID: <5585E412.8030205 at sandia.gov>
>Content-Type: text/plain; charset="utf-8"; format=flowed
>
>> Hi MueLu devs,
>>
>> I recently switched one of my apps from ML to MueLu and I'm reevaluating
>> some design decisions I took back then. For example, I vaguely remember
>> that the reason for me to have map importing/exporting going on here and
>> there was that ML required me that row and column map are equal for a
>> given
>> matrix, and that the map is unique.
>> Are these requirements still active in MueLu?
>>
>> Cheers,
>> Nico
>Nico,
>
>     I'm assume by "unique" you mean that the map is 1-to-1.  There's no
>such requirement on the column map of the matrix that you pass into the
>MueLu preconditioner constructor.  In fact, in most cases this won't be
>true.  I don't think we make any assumptions on the row map either, but
>usually we're working with an assembled matrix where the row map is 1-1.

The sparse matrix-matrix multiply routine that MueLu uses for setup
currently requires that the row Map be one to one.

mfh