Singular Matrices: Is the Matlab algorithm for CONDITON NUMBER always stable ?

Their documentation says that their algorithm for determinants can be unstable because of problems with LU factorization.

Their documenatio for cindition number - COND - does not mention stability problems, even though some algorithms use LU factorization I believe.

Answer 1

[Richard Brown]

The algorithm for condition number uses the SVD, not LU factorisation and is perfectly stable.

[John D'Errico]

Yes. As well, there are very few cases where you really want to use det for anything anyway. You certainly never want to use it to determine the singularity of a matrix, despite what they always teach students in class.