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

[Lukas Reichlin]

On 04.06.2012, at 18:56, marco atzeri wrote:

> 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

Hmm, that's interesting. I used reference blas/lapack 3.4.1 on Mac OS X 10.6 
and 10.7 without any failing tests.

Lukas