[Trilinos-Users] Solving a Reduced System

[Simone Deparis]

Mike,

I am going to use your class SubCopy_CrsMatrix, Thank you for posting it
here.

I have two questions and two notes:
Q1- Do you have a version where a view is created instead of a copy
(such that no need for fwd and rvc)?
    Do you think it is possible the way you code it?

Q2- Do you have a class that does the opposite, i.e., from several
matrices, create a global matrix? E.g., in matlab:
subA11, subA12, subA21, subA22 are given, then create
A= [ subA11, subA12
     subA21, subA22];

N1- You are filling without the domainMap,rangeMap that you have.

N2- Be careful if you are going to call operator() twice:
the fwd and rcv methods applies only to the last created instance.

Thank you
Simone



Michael A Heroux wrote:
> Ammar,
> 
> I have attached several files that will be part of the next Trilinos
> release.  The new class (SubCopy_CrsMatrix) creates a new CrsMatrix that is
> a subset of row/columns of an existing matrix by asking you to provide an
> new set of Epetra_Map objects describing the global rows and columns you
> want as part of the reduced system.  Reduced x and B vectors can be created
> directly by using an Epetra_Import object.
> 
> This very new code, but it has worked for me.  Documentation is still not
> done, but ask if you have questions.  The sample driver (cxx_main.cpp)
> should be somewhat helpful.
> 
> Mike
> 
> 
>>-----Original Message-----
>>From: trilinos-users-bounces at software.sandia.gov 
>>[mailto:trilinos-users-bounces at software.sandia.gov] On Behalf 
>>Of Ammar T. Al-Sayegh
>>Sent: Friday, October 07, 2005 4:54 PM
>>To: trilinos-users at software.sandia.gov
>>Subject: [Trilinos-Users] Solving a Reduced System
>>
>>Hi All,
>>
>>Let's say I have a system A x = B, but I would like to solve 
>>the reduced system A' x' = B', where selected rows and 
>>columns are elementated from the original system. Is there an 
>>easy way to do that in solving a an Epetra_LinearProblem with 
>>AzetecOO solver? The only related class I found is 
>>Epetra_CrsSingletonFilter, but it's for elemenating rows and 
>>columns with single entries. However, I need a class or 
>>function that would work with any selected rows/columns, 
>>regardless of how many entries in them.
>>
>>Thanks.
>>
>>
>>-ammar
>>
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>>
>>
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                                    Simone Deparis
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