[Octave-bug-tracker] [bug #53817] nonlin_residmin() fails at call to svd()

[Michael Leitner]

Follow-up Comment #3, bug #53817 (project octave):

Actually, the returned matrices as you report them for version 4.2.0
correspond to the "economy-sized" decomposition (with square matrix S, but in
the general case the larger of U or V non-square), while those for 4.4.0
correspond to the proper svd (with generally non-square matrix S, but square U
and V). The difference is just due to the fact that (according to the
documentation) between 4.2.2 and 4.4.0 a fourth way of calling svd was
introduced, namely


[U, S, V] = svd (A, 0)


Specifically giving the number zero as second argument makes the algorithm
decide which version to return. Honestly, I do not see where this should be
necessary, and incidentially the optim package seems to use just this number
zero to request the economy-sized decomposition, as it was returned up to
4.2.2, but which now received a special meaning. So instead of your proposed
modification, if you just change the computation of the svd to 


[prt,s,v]=svd(prt,1);


that should work, I think.

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