[petsc-users] MatGetValues / MatGetRow

[Smith, Barry F.]

> On May 27, 2018, at 9:39 PM, Marius Buerkle <mbuerkle at web.de> wrote:
> 
> Hi !
>  
> Are MatGetValues / MatGetRow implemented for MATELEMENTAL?

    A quick check seems to say no.

>  Or is there another way to access the elements of an ELEMENTAL matrix?

    There is no obvious way to access the elements of an Elemental matrix except to directly access the elemental data structure (which presumably is hairy) or to MatConvert(A,MATDENSE,MAT_INITIAL_MATRIX,&Adense); and then access in the dense format (note this conversion is expensive and needs to do communication).
 

    Why do you wish to access the values directly instead of use them indirectly with the API, such as matrix-vector products, factorizations etc?



   Barry

>  
> best,
> marius