[petsc-users] Advice on how to tackle with in place operation for a Matrix

[Umut Tabak]

Matthew Knepley wrote:
> 1) This must be a dense matrix, so you could directly copy in the 
> values with a strided loop
>
Dear Matt,
Thanks for the immediate reply, I guess I did not understand this.
> 2) Is there a reason for the output to be a matrix, rather than a 
> collection of vectors?
>
Collection of vectors? not sure on this point. After the 
orthogonalization, I extract some parts of the matrix and continue 
operation with these extracted parts. Are there better ways of 
conducting operations for these kinds of tasks?