[Trilinos-Users] Rectangular Epetra_CrsMatrix sparse matrices

[Alberto F. Martín-Huertas]

 Hello Chris,

 thanks for the hints. Now I managed
 to create rectangular sparse matrices.

 Regards,
  Alberto.


 On Wed, 15 Jun 2011 11:58:50 -0400, Baker, Christopher G. wrote:
> Hello Alberto,
>
> The shape of a sparse matrix, of course, isn't necessarily defined by 
> the
> entries. For Epetra, the shape of the matrix is defined by the range 
> and
> domain maps, I.e., the maps for the linear subspaces between which 
> the
> matrix is an operator.
>
> What this means is that defining a rectangular Epetra_CrsMatrix 
> consists
> of specifying distinct domain and range maps the matrix. These are 
> passed
> to FillComplete(). In the case of your example, you can pass the row 
> map
> used to construct the matrix as the range map of the matrix, but you
> should pass a 3-dimensional map as the domain map. Documentation for 
> this
> version of FillComplete() is here:
> 
> http://trilinos.sandia.gov/packages/docs/r10.6/packages/epetra/doc/html/cla
> ssEpetra__CrsMatrix.html#aac3c13275e8dbe80826e820abbb8e49c
>
>
> An example of this usage is available here:
> Trilinos/packages/epetra/test/CrsRectMatrix/cxx_main.cpp
>
> Chris
>
> On 6/15/11 11:37 AM, "Alberto F. Martín-Huertas" 
> <amartin at cimne.upc.edu>
> wrote:
>
>>
>> Dear all,
>>
>> the Epetra_CrsMatrix class reference explicitly mentions
>> that Epetra_CrsMatrix matrices can be rectangular. I have thoroghly
>> read Epetra_CrsMatrix class reference I did not manage to see
>> any further reference on how to create rectangular Epetra_CrsMatrix.
>> I tried with  piece of code below, which tries to create a 2x3
>> Epetra_CrsMatrix without success (in particular
>> it throws an uncatched exception on matrix->FillComplete()).
>>
>> I would greatly appreciate any hint on how to deal with
>> rectangular.
>>
>> Thanks.
>>
>> Best regards,
>>  Alberto.
>>
>>
>>
>> RCP<Epetra_CrsMatrix> build2x3( double a00, double a01, double a02,
>>                                 double a10, double a11, double a12,
>> Epetra_Comm & Comm)
>> {
>>    RCP<Epetra_Map> map = rcp(new Epetra_Map(2,0,Comm));
>>    RCP<Epetra_CrsMatrix> matrix = rcp(new
>> Epetra_CrsMatrix(Copy,*map,3));
>>
>>    int MyPID = Comm.MyPID();
>>    int indicies[3] = { 0, 1, 2 };
>>    double values[3];
>>
>>    int num_my_elements,   i ;
>>    int * my_global_elements ;
>>
>>    num_my_elements    = map->NumMyElements();
>>    my_global_elements = map->MyGlobalElements();
>>
>>    for ( i = 0 ; i < num_my_elements ; i++)
>>    {
>>         switch ( my_global_elements[i] )
>>         {
>>           case 0:
>>               values[0] = a00;
>>               values[1] = a01;
>>               values[2] = a02;
>>           break;
>>           case 1:
>>               values[0] = a10;
>>               values[1] = a11;
>>               values[2] = a12;
>>           break;
>>         }
>>         matrix->InsertGlobalValues(my_global_elements[i], 3,
>> values,indicies);
>>    }
>>
>>    // pack it up
>>    matrix->FillComplete();
>>
>>    return matrix;
>> }
>>
>>
>>
>>
>>
>>--
>> Alberto F. Martín-Huertas
>> Centre Internacional de Mètodes Numèrics a l'Enginyeria (CIMNE)
>> Parc Mediterrani de la Tecnologia, UPC
>> Esteve Terrades 5, Building C3, Office 207,
>> 08860 Castelldefels (Barcelona, Spain)
>> e-mail: amartin at cimne . upc . edu
>>
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