Dear Matt, Matthew Knepley <knep...@gmail.com>, 10 Haz 2020 Çar, 16:03 tarihinde şunu yazdı: > > On Wed, Jun 10, 2020 at 8:56 AM Eda Oktay <eda.ok...@metu.edu.tr> wrote: >> >> Hi all, >> >> I am trying to get all the rows of a parallel matrix as individual >> vectors. For instance, if I have 72*4 matrix, I want to get 72 >> different vectors having size 4. >> >> As far as I understood, MatGetRow is only for local rows, so >> MatGetOwnershipRange is used, however, when I tried this one, I >> couldn't get the whole and desired row vectors. >> >> In MatGetRow explanation, it is written that I should use >> MatCreateSubMatrices first, then use MatGetRow. But I couldn't >> understand to which extent I should create submatrices. I just need to >> have all 72 rows as 72 different vectors each having 4 elements. > > > 1) For sparse matrices, the storage is always divided by row, so that values > can only be retrieved for local rows with MatGetRow() > > 2) Is this matrix sparse? It sounds like it is dense.
Matrix is dense. > > 3) Are you asking to get all matrix values on all processes? If so, I think > the easiest thing to do is first wrap a Vec around the > values, then use VecScatterToAll(), then wrap each one in a MatDense > again. Yes, I want all row vectors on all processes. In a dense matrix, should I still wrap a Vec around the values? I know I should use scatter but I couldn't even wrap a Vec around them. Thanks so much! Eda > > Thanks, > > Matt > >> >> Thanks! >> >> Eda > > > > -- > What most experimenters take for granted before they begin their experiments > is infinitely more interesting than any results to which their experiments > lead. > -- Norbert Wiener > > https://www.cse.buffalo.edu/~knepley/