[SciPy-dev] Why does orth use svd instead of QR ?

[David Cournapeau]

Hi,

I wanted to know if there was a rationale for using svd to 
orthonormalize the columns of a matrix (in scipy.linalg). QR-based 
methods are likely to be much faster, and I thought this was the 
standard, numerically-stable method to orthonormalize a basis ? If the 
reason is to deal with rank-deficient matrices, maybe we could add an 
option to choose between them ?

cheers,

David