eliminate the nullspace of a matrix

14 vues (au cours des 30 derniers jours)
Ano le 7 Août 2017
Commenté : Zoltán Csáti le 20 Août 2018
Hello, how can I eliminate the nullspace of a square matrix using Matlab? Thank you!
2 commentairesAfficher AucuneMasquer Aucune
John D'Errico le 7 Août 2017
Sorry, but eliminating the nullspace of a matrix has no meaning, just some jargon that you have made up. Define carefully what you want to do. Only you know that.
A matrix has a nullspace. That null space may be empty or not. But you cannot "eliminate" it. So what do you want to do?
Torsten le 7 Août 2017
If you want a basis of the row space of A, use orth(A.').
The rule is that
null(A) + orth(A.') = R^n
where n is the dimension of your matrix.
Best wishes
Torsten.

Connectez-vous pour commenter.

Réponse acceptée

Azzi Abdelmalek le 7 Août 2017
If you have any matrix, square or not, you have only one possibility: remove entire rows or columns that are equal to zero
Example
A=[1 2 3 0;0 0 0 0;1 4 5 0 ;2 7 8 0]
ix=~any(A,1)
A(:,ix)=[]
iy=~any(A,2)
A(iy,:)=[]
1 commentaireAfficher -1 commentaires plus anciensMasquer -1 commentaires plus anciens
Zoltán Csáti le 20 Août 2018
Non-empty null space is possible without having zero rows/columns.

Connectez-vous pour commenter.

Catégories

En savoir plus sur Matrices and Arrays dans Help Center et File Exchange

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by