On Wed, Jul 1, 2020 at 6:34 AM Eda Oktay <eda.ok...@metu.edu.tr> wrote:
> Der Barry, > > ı am trying to use your way but I couldn't understand how I create sub > matrices by using MatCreateSubMatrices() since as input, the function > needs const IS instead of IS and I couldn't understand how to get a > const IS. I tried to use ISCreateStride since this IS should be 0:71 > because as you mentioned, the sub matrix should consist of the entire > matrix. However, since ISCreateStride produces IS, not const IS, I > couldn't use it in MatCreateSubMatrices(). > The 'const' refers to the array, not the IS: https://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/Mat/MatCreateSubMatrices.html Thanks, Matt > Thanks > > Eda > > Barry Smith <bsm...@petsc.dev>, 10 Haz 2020 Çar, 19:59 tarihinde şunu > yazdı: > > > > > > You can use MatCreateSubMatrices() with each process getting a single > sequential dense sub matrix that consists of the entire matrix. > > > > Use VecDuplicateVecs() to create an array of 72 vectors (create a > single seq vector of size 4 as the input to this routine) > > > > Then use MatDenseGetArrayRead() to access the upper left corner of the > new sequential dense matrix > > > > Loop over the vectors calling VecGetArray() > > Then loop over the row of the dense array filling up the vector > > > > Because dense matrices are stored by column, you have to do this > looping to fill up the vectors, they can't share the space with the matrix. > > > > Barry > > > > > > > > On Jun 10, 2020, at 11:36 AM, Matthew Knepley <knep...@gmail.com> wrote: > > > > On Wed, Jun 10, 2020 at 12:26 PM Eda Oktay <eda.ok...@metu.edu.tr> > wrote: > >> > >> Matthew Knepley <knep...@gmail.com>, 10 Haz 2020 Çar, 19:13 tarihinde > >> şunu yazdı: > >> > > >> > On Wed, Jun 10, 2020 at 12:07 PM Eda Oktay <eda.ok...@metu.edu.tr> > wrote: > >> >> > >> >> Der Matt, > >> >> > >> >> When I looked at the results, I found that there are some problems I > >> >> couldn't understand. > >> >> > >> >> First of all, I am working on a 72*4 matrix and as I said before, I > >> >> want to have 72 different vectors having size 4 each, whose elements > >> >> consist of the elements in the same row. And of course, all vectors > >> >> should be in all processors (currently I am using 4 processors). > >> >> > >> >> When I use your scatter code, the output vector is divided into 4 > >> >> parts for 4 processors and each vector consists of 18 row vectors > >> >> whose elements are arranged in a way that if I want to find zeroth > row > >> >> vector, its elements are located in 0th,18th,36th,54th elements. > >> > > >> > > >> > Was the global size of the vector you wrapped around the dense matrix > 72*4? > >> > >> Yes it is. I set up its global size to 72*4. > >> > >> > > >> > If you use CreateToAll(), it will make a vector on each process which > has the global size of the original vector. > >> > >> Although I set 72*4, the size of the vectors in each process is 72. > > > > > > You can understand how it is hard to accept, as this code is tested > every night. Can you VecView() the input vector > > to CreateToAll and the output vector, and send that output? > > > > Thanks, > > > > Matt > > > >> > >> Thanks, > >> > >> Eda > >> > >> > > >> > Thanks, > >> > > >> > Matt > >> > > >> >> > >> >> So, isn't scatter's goal is to scatter all values to all processors? > >> >> > >> >> Furthermore, I am trying to use my vectors in that way but isn't > there > >> >> any possible way that I can reach my goal entirely? > >> >> > >> >> Thanks so much for your help, > >> >> > >> >> Eda > >> >> > >> >> Matthew Knepley <knep...@gmail.com>, 10 Haz 2020 Çar, 18:11 > tarihinde > >> >> şunu yazdı: > >> >> > > >> >> > On Wed, Jun 10, 2020 at 10:09 AM Eda Oktay <eda.ok...@metu.edu.tr> > wrote: > >> >> >> > >> >> >> Dear Matt, > >> >> >> > >> >> >> I have one last question I believe. Up to creating a dense matrix > I > >> >> >> did what you've suggested. Thank you so much for that. > >> >> >> > >> >> >> I created a new dense matrix. Now, how should I wrap each vector > in a > >> >> >> MatDense again? I mean, what is wrapping vectors in a matrix? To > put > >> >> >> each of them again as rows? > >> >> > > >> >> > > >> >> > I thought you need a dense matrix for something, since you started > with one. If you > >> >> > do not, just do VecGetArray() on the vector from CreateToAll and > use the values. > >> >> > > >> >> > Thanks, > >> >> > > >> >> > Matt > >> >> > > >> >> >> > >> >> >> Thanks! > >> >> >> > >> >> >> Eda > >> >> >> > >> >> >> Matthew Knepley <knep...@gmail.com>, 10 Haz 2020 Çar, 16:16 > tarihinde > >> >> >> şunu yazdı: > >> >> >> > > >> >> >> > On Wed, Jun 10, 2020 at 9:08 AM Eda Oktay < > eda.ok...@metu.edu.tr> wrote: > >> >> >> >> > >> >> >> >> 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. > >> >> >> > > >> >> >> > > >> >> >> > I would do > >> >> >> > > >> >> >> > MatGetSize(&N); > >> >> >> > MatGetLocalSize(&m); > >> >> >> > > https://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/Mat/MatDenseGetArray.html > >> >> >> > <create vector of local size m*N> > >> >> >> > > https://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/Vec/VecPlaceArray.html > >> >> >> > > https://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/Vec/VecScatterCreateToAll.html > >> >> >> > <do scatter> > >> >> >> > > https://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/Vec/VecResetArray.html#VecResetArray > >> >> >> > > https://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/Mat/MatCreateDense.html > >> >> >> > <use it> > >> >> >> > <destroy matrix> > >> >> >> > <destroy vector from CreateToAll> > >> >> >> > > >> >> >> > Thanks, > >> >> >> > > >> >> >> > Matt > >> >> >> > > >> >> >> >> > >> >> >> >> 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/ > >> >> >> > > >> >> >> > > >> >> >> > > >> >> >> > -- > >> >> >> > 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/ > >> >> > > >> >> > > >> >> > > >> >> > -- > >> >> > 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/ > >> > > >> > > >> > > >> > -- > >> > 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/ > > > > > > > > -- > > 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/ > > > > > -- 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/ <http://www.cse.buffalo.edu/~knepley/>
