> On Aug 26, 2015, at 3:06 PM, Nicolas Pozin <nicolas.po...@inria.fr> wrote: > > Thank you for this answer. > > What I want to do is to get the lines of this matrix and store them in > vectors.
If you want to treat the columns of the dense matrix as vectors then use MatDenseGetArray() and call VecCreateMPIWithArray() with a pointer to the first row of each column of the obtained array (PETSc dense matrices are stored by column; same as for example LAPACK). But if you explained more why you want to treat something sometimes as a Mat (which is a linear operator on vectors) and sometimes as vectors we might be able to suggest how to organize your code. Barry > > > ----- Mail original ----- >> De: "Jed Brown" <j...@jedbrown.org> >> À: "Nicolas Pozin" <nicolas.po...@inria.fr>, petsc-users@mcs.anl.gov >> Envoyé: Mercredi 26 Août 2015 20:38:37 >> Objet: Re: [petsc-users] forming a matrix from a set of vectors >> >> Nicolas Pozin <nicolas.po...@inria.fr> writes: >>> Given a set of vectors V1, V2,...,Vn, is there an efficient way to form the >>> dense matrix [V1 V2 ... Vn]? >> >> What do you want to do with that matrix? The vector representation is >> pretty flexible and the memory semantics are similar unless you store >> the dense matrix row-aligned (not the default). >>
