[Trilinos-Users] is there Epetra_Outerproduct?

[Heroux, Michael A]

In this case, unless there is a specific external reason to form the explicit matrix, the best way to use this operator is to apply it implicitly:

If your operator is C = A X B' (using your notation below) and you want to compute the vector y = C x, where x is a known vector, you would apply:


  1.  alpha = dot(B,x)
  2.  y = alpha * A

Also, since C is rank 1 (each column of C is a scalar multiple of the first column), I am guessing you are combining C with some other operator.  In any case, you would implement the operator using Epetra_Operator.

Mike

From: Sunghwan Choi <sunghwanchoi91 at gmail.com<mailto:sunghwanchoi91 at gmail.com>>
Date: Tuesday, February 26, 2013 12:24 AM
To: Michael Heroux <maherou at sandia.gov<mailto:maherou at sandia.gov>>
Subject: [EXTERNAL] RE: [Trilinos-Users] is there Epetra_Outerproduct?

What I want to do is that


A X B’ =

           a1b1     a1b2     a1b3  ……         a1bn
           a2b1     a2b2     a2b3 …….
           .
           .
.
.
           anb1     anb2     anb3 …….          anbn

where A’=[a1,a2,a3,a4,…..,an] B’=[b1,b2,b3,b4,….,bn]

does it make sense?

Sunghwan Choi


From: Heroux, Michael A [mailto:maherou at sandia.gov]
Sent: Tuesday, February 26, 2013 1:18 PM
To: SungHwan Choi
Cc: trilinos-users at software.sandia.gov<mailto:trilinos-users at software.sandia.gov>
Subject: Re: [Trilinos-Users] is there Epetra_Outerproduct?

What is the specific mathematical operation you want to perform?

From: SungHwan Choi <sunghwanchoi91 at gmail.com<mailto:sunghwanchoi91 at gmail.com>>
Date: Monday, February 25, 2013 7:48 PM
To: "trilinos-users at software.sandia.gov<mailto:trilinos-users at software.sandia.gov>" <trilinos-users at software.sandia.gov<mailto:trilinos-users at software.sandia.gov>>
Subject: [EXTERNAL] [Trilinos-Users] is there Epetra_Outerproduct?

Hi,
I am finding Epetra_Outer_product. I tried to find it in Epetra or EpetraExt class references but I failed. Is there any good way to do outer product?
Of course, I can program it but I think the performance of given method is much better than what I code.
If you know how to deal outer product, please let me know
Sunghwan Choi
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