[Trilinos-Users] Epetra_SerialDenseVector vs. Teuchos::SerialDenseVector

[Pawlowski, Roger P]

You could do it efficiently with expression templates.  Not sure if it is worth the time investing...

Roger



________________________________________
From: trilinos-users-bounces at software.sandia.gov [trilinos-users-bounces at software.sandia.gov] On Behalf Of Nico Schlömer [nico.schloemer at ua.ac.be]
Sent: Sunday, August 01, 2010 6:46 PM
To: Bartlett, Roscoe A
Cc: Heroux, Michael A; Thornquist, Heidi K; trilinos-users at software.sandia.gov
Subject: Re: [Trilinos-Users] Epetra_SerialDenseVector vs. Teuchos::SerialDenseVector

> It is very hard to make operator+, operator-, operator* efficient.

I see.
Would you have any recommendation for me what to do with expression like

   y = alpha * x1 + beta * x2 + ...

?

--Nico



On Sun, 1 Aug 2010 18:25:25 -0600, "Bartlett, Roscoe A"
<rabartl at sandia.gov> wrote:
> It is very hard to make operator+, operator-, operator* efficient.
>
> - Ross
>
>
>> -----Original Message-----
>> From: trilinos-users-bounces at software.sandia.gov [mailto:trilinos-
>> users-bounces at software.sandia.gov] On Behalf Of Nico Schlömer
>> Sent: Sunday, August 01, 2010 6:04 PM
>> To: Thornquist, Heidi K
>> Cc: Heroux, Michael A; trilinos-users at software.sandia.gov
>> Subject: Re: [Trilinos-Users] Epetra_SerialDenseVector vs.
>> Teuchos::SerialDenseVector
>>
>> > Thus any further development of the SerialDense classes will be done
>> in
>> Teuchos,
>>
>> Suggestion for the further development: Adding
>>
>>   operator+
>>   operator-
>>
>> and scalar multiplication. This is now all possible with operator+= and
>> friends, but I just had to evaluate an expression 'a la
>>
>>    y = alpha * x1 + beta * x2 + gamma * x3 + delta * x4
>>
>> where the x{1,2,3,4} are SerialDenseVectors, alpha,.. are scalars and
>> found the only way to do so
>>
>> SerialDenseVector y;
>> x *= alpha;
>> y += x;
>> [...]
>>
>> The code for the new operators would rather go in SerialDense~Matrix~,
>> though, I guess.
>>
>> Cheers,
>> Nico
>>
>>
>>
>> On Tue, 27 Jul 2010 11:20:35 -0600, "Thornquist, Heidi K"
>> <hkthorn at sandia.gov> wrote:
>> > Hi Nico,
>> >
>> > There has been some work to add functionality in Teuchos to support
>> the
>> use
>> > of Teuchos::SerialDenseVector with Teuchos::SerialDenseMatrix.  This
>> > functionality
>> > was in support of Dakota's use of Teuchos::SerialDenseVector.  Thus
>> any
>> > further
>> > development of the SerialDense classes will be done in Teuchos,
>> probably
>> > not in
>> > Epetra.
>> >
>> > Heidi
>> >
>> >
>> > On 7/27/10 11:10 AM, "Heroux, Michael A" <maherou at sandia.gov> wrote:
>> >
>> > Nico,
>> >
>> > My advice is that, if there is functionality overlap between Epetra
>> and
>> > Teuchos, you should use Teuchos.  Historically, we have migrated a
>> lot
>> of
>> > Epetra functionality into Teuchos, generalizing it as part of the
>> > migration.
>> > This is what happened in this case.
>> >
>> > Mike
>> >
>> >
>> > On 7/27/10 12:00 PM, "Christopher Grover Baker" <bakercg at ornl.gov>
>> wrote:
>> >
>> >> Nico,
>> >>
>> >> Aside from the fact that Teuchos::SerialDenseVector is templated on
>> the
>> >> underlying scalar type and Epetra_SerialDenseVector is hard-coded to
>> >> double,
>> >> there should not be much difference between the two. The Epetra
>> object
>> >> will
>> >> see little use outside of Epetra, while the Teuchos object will be
>> used
>> >> by
>> >> templated packages. Although, to be honest, I can't think of any use
>> of
>> >> Teuchos::SerialDenseVector in any of the templated packages that I
>> work
>> >> on
>> >> (including Tpetra).
>> >>
>> >> Chris
>> >>
>> >>
>> >> On 7/27/10 12:10 PM, "Nico Schlömer" <nico.schloemer at ua.ac.be>
>> wrote:
>> >>
>> >> Hi all,
>> >>
>> >> I just saw that for the Epetra_SerialDenseVector class I've always
>> used
>> >> there seems to be an equivalent in Teuchos::SerialDenseVector.
>> >>
>> >> Is the use of one of the two classes recommended over the other?
>> >>
>> >> Cheers,
>> >> Nico
>> >>
>> >>
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>> >>
>> >>
>> >>
>> >>
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>> >
>> >
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