[petsc-users] Is there something to be paid attention to about MatIsSymmetric?

[w_ang_temp]

Maybe the matrix in my project is true unsymmetric. I use MatIsTranspose and get
the same result. Maybe I need to check my constitutive model.




>At 2012-12-02 23:10:51,"Jed Brown" <jedbrown at mcs.anl.gov> wrote:
>The test for symmetry is not implemented for all matrix types. Looking at the code, it seems to only be SeqAIJ, but MatIsTranspose(A,A,...) would also work >for MPIAIJ.



>>On Sun, Dec 2, 2012 at 8:45 AM, w_ang_temp <w_ang_temp at 163.com> wrote:


>>Hello,

>>    I use MatIsSymmetric to know if the matrix A is symmetric.

>>According to my model, it should be symmetric due to the theory.

>>But I always get the result 'PetscBool  *flg = 0', although I

>>set 'tol' a large value(0.001).

>>    Because the matrix is of 20000 dimension, I can not output the

>>matrix to the txt. So I want to konw if there is something to be paid attention to

>>about the function 'MatIsSymmetric' in version 3.2. Or do I have some other ways

>>to determine the symmetry.I think symmetry is one of the most important thing

>>in my analysis.

>>    Thanks.

>>                                               Jim





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