[Trilinos-Users] Solving a Reduced System

Simone Deparis deparis at MIT.EDU
Mon Oct 17 08:17:08 MDT 2005


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

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

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.
>>Trilinos-Users mailing list
>>Trilinos-Users at software.sandia.gov
>>Trilinos-Users mailing list
>>Trilinos-Users at software.sandia.gov

                                    Simone Deparis
  .~.                               Mech Eng Dept - MIT
  /V\   L   I   N   U   X           77 Mass Ave Room 3-264
 // \\  =================           Cambridge MA 02139
/(   )\                             USA
phone :  +1 617 452 3285  mailto:deparis at mit.edu
fax   :  +1 617 258 8559  http://www.mit.edu/~deparis

More information about the Trilinos-Users mailing list