MatNormApproximate#

Approximate the norm of a matrix.

Synopsis#

#include "petscmat.h" 
PetscErrorCode MatNormApproximate(Mat A, NormType normtype, PetscInt maxit, PetscReal *n)

Collective

Input Parameters#

A - the matrix
normtype - the NormType
maxit - maximum number of iterations to use

Output Parameter#

n - the norm estimate

Notes#

Does not need access to the matrix entries; it just performs matrix-vector and transposed matrix-vector products [Hig92], [HT00].

If maxit is negative, a default number of iterations (10 for NORM_1 and NORM_INFINITY and 20 for NORM_2) is performed.

References#

[Hig92]

Nicholas J. Higham. Estimating the matrix $p$-norm. Numerische Mathematik, 62(4):539–556, 1992.

[HT00]

Nicholas J. Higham and Françoise Tisseur. A block algorithm for matrix 1-norm estimation, with an application to 1-norm pseudospectra. SIAM Journal on Matrix Analysis and Applications, 21(4):1185–1201, 2000.

Level#

intermediate

Location#

src/mat/interface/matrix.c

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