Re: [petsc-users] Compute the sum of the absolute values of the off-block diagonal entries of each row

2019-03-04 Thread Smith, Barry F. via petsc-users
How about something like, MatMPIAIJGetSeqAIJ(A,NULL,,NULL); > MatGetOwnershipRange(A, , ); > for (r = 0; r < rE-rS; ++r) { > sum = 0.0; > MatGetRow(Ao, r, , NULL, ); > for (c = 0; c < ncols; ++c) sum += PetscAbsScalar(vals[c]); // do what you need with sum > } Barry > On

Re: [petsc-users] Compute the sum of the absolute values of the off-block diagonal entries of each row

2019-03-04 Thread Jed Brown via petsc-users
"Zhang, Junchao via petsc-users" writes: > Perhaps PETSc should have a MatGetRemoteRow (or > MatGetRowOffDiagonalBlock) (A, r, , , ). MatGetRow() > internally has to allocate memory and sort indices and values from > local diagonal block and off-diagonal block. It is totally a waste in > this

Re: [petsc-users] Compute the sum of the absolute values of the off-block diagonal entries of each row

2019-03-04 Thread Zhang, Junchao via petsc-users
On Mon, Mar 4, 2019 at 10:39 AM Matthew Knepley via petsc-users mailto:petsc-users@mcs.anl.gov>> wrote: On Mon, Mar 4, 2019 at 11:28 AM Cyrill Vonplanta via petsc-users mailto:petsc-users@mcs.anl.gov>> wrote: Dear Petsc Users, I am trying to implement a variant of the $l^1$-Gauss-Seidel

[petsc-users] Compute the sum of the absolute values of the off-block diagonal entries of each row

2019-03-04 Thread Cyrill Vonplanta via petsc-users
Dear Petsc Users, I am trying to implement a variant of the $l^1$-Gauss-Seidel smoother from https://doi.org/10.1137/100798806 (eq. 6.1 and below). One of the main issues is that I need to compute the sum $\sum_j |a_{i_j}|$ of the matrix entries that are not part of the local diagonal block.

[petsc-users] Loading only upper + MatSetOption(A,MAT_SYMMETRIC,PETSC_TRUE);

2019-03-04 Thread Klaus Burkart via petsc-users
Hello, I want to solve many symmetric linear systems one after another in parallel using boomerAMG + KSPCG  and need to make the matrix transfer more efficient. Matrices are symmetric in structure and values. boomerAMG + KSPCG work fine. So far I have been loading the entire matrices but I