[Octave-bug-tracker] [bug #55710] svd may sometimes return -0 for exactly zero singular values

[Tim Mitchell]

Follow-up Comment #4, bug #55710 (project octave):

@Rik:

1) I agree that this -0 is likely to be an upstream issue with LAPACK. 
Fortunately, it's easy to fix so I imagine it won't be too long from them to
handle it on their end.

2) In the meantime, having Octave implement a temporary workaround would be
ideal.  It's debatable which is better but I think S(S==0)=0 is better than
abs(S).  I doubt there's a difference speedwise.  But if there's ever a bug
where the SVD routines return a negative singular value, with S(S==0)=0, that
negative value would still get passed to the user so someone might actually
notice something is really wrong.  With abs(S), we'd never know.  

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