Re: control-2.3.51 released in package forum - please upload

[marco atzeri]

On 6/4/2012 5:37 PM, Lukas Reichlin wrote:
> On 03.06.2012, at 21:45, Sergei Steshenko wrote:
>
>
>
> I would not call your ATLAS defective. For various reasons, results from ATLAS 
> and Reference BLAS/LAPACK can differ. Remember that ATLAS stands for 
> _Automatically_ _Tuned_ Linear Algebra Software :-)
>
> Your results from the failing tests are probably not wrong: Just compare the 
> observed and the expected state-space models. There are several ways to do this:
> - poles and zeros should be the same
> - Hankel singular values should be the same
> - plots from time and frequency responses look the same
> - solve the equations below for the diagonal transformation matrix T, its 
> entries should be -1 and 1. (Because in your example, the absolute values are 
> the same)
>
> Aexp = T \ Aobs * T
> Bexp = T \ Bobs
> Cexp =      Cobs * T
>
> To sum up: if there is a state transformation between observed and expected 
> model, your results are correct.
>
> Remember that the SLICOT authors recommend reference BLAS/LAPACK and use it for 
> their test cases (which I use for test_control). If confidence in correct 
> results is more important to you than a few milliseconds speed advantage from 
> automatic tuning, then you should follow their advice.
>
> Hope this helps,
> Lukas

Lukas,
I had same of Sergei's faults (2 of 3) and I am using the
reference blas/lapack 3.4.1

I expect a package test function to behave reasonable correctly
for most of the system. Borderline case or alternative valid solution
should be avoided.

Regards
Marco