Is the MatMumpsGetInverse also wrapped to the python version in PETSc4py ? If yes is there any example for using it ? My other question is related to the LU factoriation ( https://www.mcs.anl.gov/petsc/documentation/faq.html#invertmatrix). Is the LU factorization only possible for sequential Aij matrices ? I read in the docs that this is the case for ordering. After setting up my matrix A, B and x i tried: r, c = dynamical_matrix_nn.getOrdering("nd") fac_dyn_matrix = dynamical_matrix_nn.factorLU(r,c)
resulting in an error: [0] No support for this operation for this object type [0] Mat type mpiaij Am Fr., 27. Sept. 2019 um 16:26 Uhr schrieb Zhang, Hong <[email protected] >: > See ~petsc/src/mat/examples/tests/ex214.c on how to compute selected > entries of inv(A) using mumps. > Hong > > On Fri, Sep 27, 2019 at 8:04 AM Smith, Barry F. via petsc-users < > [email protected]> wrote: > >> >> MatMumpsGetInverse() maybe useful. Also simply using MatMatSolve() with >> the first 1000 columns of the identity and "throwing away" the part you >> don't need may be most effective. >> >> Barry >> >> >> >> > On Sep 27, 2019, at 3:34 AM, Jan Grießer via petsc-users < >> [email protected]> wrote: >> > >> > Hi all, >> > i am using petsc4py. I am dealing with rather large sparse matrices up >> to 600kx600k and i am interested in calculating a part of the inverse of >> the matrix(I know it will be a dense matrix). Due to the nature of my >> problem, I am only interested in approximately the first 1000 rows and 1000 >> columns (i.e. a large block in the upper left ofthe matrix). Before I >> start to play around now, I wanted to ask if there is a clever way to >> tackle this kind of problem in PETSc in principle. For any input I would be >> very grateful! >> > Greetings Jan >> >>
