[Trilinos-Users] Creating linear operators by combining other linear operators
Bartlett, Roscoe A
rabartl at sandia.gov
Fri Jul 1 08:48:22 MDT 2011
With the magic of Thyra::EpetraOperatorWapper shown at:
you can use all of the Thyra composite operator classes and still get back an Epetra_Operator in the end. There is no need to write any new software for this.
> -----Original Message-----
> From: trilinos-users-bounces at software.sandia.gov [mailto:trilinos-
> users-bounces at software.sandia.gov] On Behalf Of Baker, Christopher G.
> Sent: Friday, July 01, 2011 8:37 AM
> To: Einar Otnes; trilinos-users at software.sandia.gov
> Subject: Re: [Trilinos-Users] Creating linear operators by combining
> other linear operators
> Hi Einar,
> There are a few different linear operator interfaces in Trilinos. Most
> notably, there are Epetra and Thyra.
> Supporting composite linear operators in Thyra is more straight-forward
> than Epetra, because the linear operator interface is based on
> y = alpha*Op*x + beta*y
> whereas Epetra's linear operator interface is
> y = Op*x
> As such, Thyra has significant support for composite operators of many
> different forms. I have used these in the past, and they are very
> convenient. See, for example, the "Composite and other linear operator
> base classes" under the THyra operator/vector extended interfaces at
> following URL:
> In particular, the one that you are looking for is here:
> As for Epetra, I don't know of an implementation to support this. It
> should be straightforward to write one, and to encapsulate it into an
> Epetra_Operator implementation.
> On 7/1/11 6:24 AM, "Einar Otnes" <eotnes at gmail.com> wrote:
> >Dear experts,
> >I have a question related to constructing linear operators in
> >Are there any packages in trilinos that support constructing new
> >operators from previously defined ones.
> >In other words, say I want to do two operations
> >y = A(x)
> >z = B(y)
> >Is there a way I can combine the two operators such that
> >z=B(y) = B(A(x)) = (BA)(x) = C(x) , where C is now a new operator
> >generated from B and A?
> >Trilinos-Users mailing list
> >Trilinos-Users at software.sandia.gov
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