[scilab-Users] RE [scilab-Users] termination indicator in lsqrsolve

[Vincent COUVERT]

Hi,

Here is the related bug report: 
http://bugzilla.scilab.org/show_bug.cgi?id=11203

Regards.

Le 29/05/12 15:44, Michael BAUDIN a écrit :
> Hi,
>
> In the source code, we find the following comments :
>
> info = 2  relative error between two consecutive iterates is at most 
> xtol.
> info = 5  number of calls to fcn with iflag = 1 has reached maxfev.
>
> Notice that this is different from the content of the help page (by 
> the way, this is a bug which should be reported). So I guess that the 
> info=2 either means that the solution is found, or that the algorithm 
> stagnates. Did you check the value of the gradient and the eigenvalues 
> of the Hessian matrix ? You can do this with the "derivative" function 
> and the "order" option.
>
> One thing that we may try in this situation is to compute the 
> derivatives by different ways, with the goal of measuring the 
> sensitivity of the solution to the accuracy of the gradient. Did you 
> try to compute the gradient with "derivative" and various formula 
> orders ? You can do this with the fjac argument of lsqrsolve.
>
> Best regards,
>
> Michael
>
> PS
> http://gitweb.scilab.org/?p=scilab.git;a=blob_plain;f=scilab/modules/optimization/src/fortran/minpack/lmder.f;hb=HEAD 
>
> http://gitweb.scilab.org/?p=scilab.git;a=blob_plain;f=scilab/modules/optimization/src/fortran/minpack/lmdif.f;hb=HEAD 
>
>
>
>
>
> *ezequielsoule at gmail.com*
>
> 28/05/2012 19:13
> Veuillez répondre à
> users at lists.scilab.org
>
>
> 	
> A
> 	users at lists.scilab.org
> cc
> 	
> Objet
> 	[scilab-Users] termination indicator in lsqrsolve
>
>
>
> 	
>
>
>
>
>
> hello, I´m using the function lsqrsolve and I wonder what is the 
> difference
> between the termination indicator 2 and 5, and what can I do if I get the
> "2".
>
> 2: number of calls to fcn reached
> 5: number of calls to fcn reached or exceeded maxfev
>
> I´m getting the termination indicator 2, and there is no way to avoid 
> it. I
> increased maxev but nothing happens, so I can´t get a good solution.
>
> Thank you,
>
>
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