[Trilinos-Users] [EXTERNAL] Extracting not-necessarily-local entries from Epetra_RowMatrix

[Jesse Chan]

Alan
Thanks for the response.  It sounds like once an Epetra matrix is assembled
then, it becomes very difficult to extract global information.  Is there a
way to access non-local information at all after a GlobalAssemble?

Jesse

On Wed, Aug 22, 2012 at 2:16 PM, Williams, Alan B <william at sandia.gov>wrote:

>  Jesse,
> As I recall, epetra matrices do not allow accessing entries for rows that
> are not local in the row-map. I don't believe FECrsMatrix allows this
> either. Once FECrsMatrix has been 'GlobalAssemble()'d, it no longer has
> local copies of the non-local entries.
> Alan
>
>  ------------------------------
> *From:* trilinos-users-bounces at software.sandia.gov [
> trilinos-users-bounces at software.sandia.gov] on behalf of Jesse Chan [
> jchan985 at gmail.com]
> *Sent:* Wednesday, August 22, 2012 12:50 PM
> *To:* trilinos-users at software.sandia.gov
> *Subject:* [EXTERNAL] [Trilinos-Users] Extracting not-necessarily-local
> entries from Epetra_RowMatrix
>
>  I'm trying to pull out a sub-matrix of entries from an Epetra_RowMatrix
> that I get from an Epetra_LinearProblem.  However, I can't seem to figure
> out how to actually access the entries - is there some way (short of a cast
> into what I know the matrix to be, a FECrsMatrix) to access terms given a
> list of global indices?
>
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