How to get information about the off-diagonal submatrix

Hi, how is it possible to print just the off-diagonal submatrix of one process of a parallel mpiaij matrix? Thomas

How to get information about the off-diagonal submatrix

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How to get information about the off-diagonal submatrix

alternatively - just access the private datastructe and print.. #include ../src/mat/impls/aij/mpi/mpiaij.h Mat_MPIAIJ *mpiaij = (Mat_MPIAIJ*)mat-data; MatView(mpiaij-B,...); Satish On Mon, 10 Aug 2009, Matthew Knepley wrote: If this is just for debugging, the easiest way I think is to

cannot find -lustdio with matlab on

weiwei, The easist way is run your petsc code with the option '-mat_view_matlab', and dump it into a file. Then use Matlab to load it for whatever you want to investigate. See petsc user manual on Using Matlab with PETSc. Hong On Mon, 10 Aug 2009, Weiwei Wang wrote: Dear All, I want to

cannot find -lustdio with matlab on

You don't need to install petsc with matlab for this. You can just use '-mat_view_matlab' - or PETSC_VIEWER_MATLAB in your code. Satish On Mon, 10 Aug 2009, Weiwei Wang wrote: Dear All, I want to check the determinant of some sparse matrix in petsc but I didn't know how to do it using

How to get information about the off-diagonal submatrix

Thanks, that works fine! In my test case (yes, just for debugging!) I've expected to have an empty off-diagonal matrix. But the matrix is not empty. But how is it possible, when all entries, which are inserted to the matrix via MatSetValues, have indices for row and col within the ownership

How to get information about the off-diagonal submatrix

You'll have to look at the code that does MatSetValues(). Perhaps you can run the code in debugger - and set a break point in MatSetValues_MPIAIJ - and see when MatSetValues_SeqAIJ_B_Private() is getting called.. Its also possible that some values are set on other procs and commuincated.. Note:

How to get information about the off-diagonal submatrix

Satish Balay wrote: Its also possible that some values are set on other procs and commuincated.. That's the reason, I've forgotten to check it. Thanks for the hint! Is there any way to get information from petsc to check how many matrix entries had to be communicated during assembling?

How to get information about the off-diagonal submatrix

Thank you for all the hints, this will help me to debug my application!!! Thomas Satish Balay wrote: On Mon, 10 Aug 2009, Thomas Witkowski wrote: Satish Balay wrote: Its also possible that some values are set on other procs and commuincated.. That's the reason, I've

Off topic - Some advice on solving Navier-Stokes with Finite Difference

Hi all, Sorry for this off-topic post. I am helping a master studnet which is working on solving Navier-Stokes equation with Finite Difference method. She is trying to eliminate spourious pressure modes from the solution. She needs to know some details that are not usually found in the papers

cannot find -lustdio with matlab on

You should really use the PetscViewerBinaryOpen() then use bin/ matlab/PetscBinaryRead() to read the matrices and vectors into Matlab. Barry On Aug 10, 2009, at 10:10 PM, Weiwei Wang wrote: Thanks a lot, it's ok using the code PetscViewer viewer;