On Jun 16 2008, Anders Logg wrote:
>On Sat, Jun 14, 2008 at 05:31:56PM -0400, Hatef Monajemi wrote:
>>
>> Hello,
>>
>> I am trying to solve a problem with different parameters; I am having a
>> loop and each time I am getting a solution vector (say Function u1) and
>> I need to save each vector as a column of an arbitrary matrix in dolfin
>> (say Matrix S). I would appreciate if you let me know how it is
>> possible. I tried the following scheme:
>>
>> Loop over i:
>>
>> Matrix S;
>> d=u1.vector();
>>
>> for(j)
>> {
>> S(i,j)=d(j);
>> {
>>
>> But it is not going to work! any help on this matter is appreciated.
>>
>>
>> Hatef:)
>
>Accessing columns in our sparse matrices is very inefficient. You
>could use a dense matrix, but I suggest storing each solution to a
>separate file as a Function:
>
> file << u1;
>
Columns can be accessed efficiently using a uBlasMatrix with an underlying
uBLAS column-major matrix, e.g.
uBlasMatrix<ublas_sparse_matrix_cmajor> A;
What won't then work well is zeroing rows to apply boundary conditions.
Garth
>
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