MatIsSymmetric#
Test whether a matrix is symmetric
Synopsis#
#include "petscmat.h"
PetscErrorCode MatIsSymmetric(Mat A, PetscReal tol, PetscBool *flg)
Collective
Input Parameters#
A - the matrix to test
tol - difference between value and its transpose less than this amount counts as equal (use 0.0 for exact transpose)
Output Parameter#
flg - the result
Notes#
For real numbers MatIsSymmetric() and MatIsHermitian() return identical results
If the matrix does not yet know if it is symmetric or not this can be an expensive operation, also available MatIsSymmetricKnown()
One can declare that a matrix is symmetric with MatSetOption(mat,MAT_SYMMETRIC,PETSC_TRUE) and if it is known to remain symmetric
after changes to the matrices values one can call MatSetOption(mat,MAT_SYMMETRY_ETERNAL,PETSC_TRUE)
See Also#
Matrices, Mat, MatTranspose(), MatIsTranspose(), MatIsHermitian(), MatIsStructurallySymmetric(), MatSetOption(), MatIsSymmetricKnown(),
MAT_SYMMETRIC, MAT_SYMMETRY_ETERNAL
Level#
intermediate
Location#
Examples#
src/ksp/ksp/tutorials/ex57f.F90
src/ksp/ksp/tutorials/ex72.c
Implementations#
MatIsSymmetric_SeqDense() in src/mat/impls/dense/seq/dense.c
MatIsSymmetric_IS() in src/mat/impls/is/matis.c
Index of all Mat routines
Table of Contents for all manual pages
Index of all manual pages