[Numpy-discussion] Problem in LinearAlgebra?

Jochen Küpper jochen at jochen-kuepper.de
Sun Nov 2 08:47:12 CST 2003


On Sun, 02 Nov 2003 17:25:34 +0100 Rob Hooft wrote:

Rob> -        lapack_routine = lapack_lite.dgelss
Rob> +        lapack_routine = lapack_lite.dgelsd

Well, here the underlying LAPACK routine was changed to the newer and
significantly faster divide-and-conquer routine. (Same holds for
complex version.) This could be the problem, which you should test.
See LAPACK documentation for details.

Nevertheless I would advise against reversing that change, as
performance diffferences can really be large (although I haven't used
either one of these specific functions here). Maybe you can keep a
copy of the old version in your own project if really necessary?
(After all there seems to be some agreement that you were just "lucky"
to find a working algorithm in the first place.)

Greetings,
Jochen
-- 
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        (Part 3 you find in my messages before fall 2003.)





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