Re: Random timing results with 'fsolve'

[Francesco Potortì]

>
>On Wed, Oct 12, 2011 at 04:21:57PM +0200, Søren Hauberg wrote:
>> ons, 12 10 2011 kl. 14:02 +0000, skrev bpabbott:
>> > It does look strange.
>> > 
>> > 
>> > Have you looked at the 2nd (function values) and 3rd (termination
>> > status) outputs of fsolved?
>> 
>> Hmm, okay... it seems like the algorithm converges to different solution
>> each time. The problem I'm solving is under-determined so it does not
>> surprise me that the solver can converge to different solutions, but I
>> am surprised that this happens when the solver is given the same
>> starting conditions. Does 'fsolve' perform any random steps?
>> 
>> Søren
>
>Wild guess: hardware floating point randomness (maybe due to
>differences between processor cores?) which has only "negligible"
>effect on accuracy, but could change the course of optimization in
>under-determined problems...

???  What is hardware floating point randomness?  As far as I know,
floating point is deterministic, on a given processor.

-- 
Francesco Potortì (ricercatore)        Voice:  +39.050.315.3058 (op.2111)
ISTI - Area della ricerca CNR          Mobile: +39.348.8283.107
via G. Moruzzi 1, I-56124 Pisa         Fax:    +39.050.315.2040  
(entrance 20, 1st floor, room C71)     Web:    http://fly.isti.cnr.it