[SciPy-dev] cgemv test failure

Nils Wagner nwagner at iam.uni-stuttgart.de
Wed Jun 28 02:28:41 CDT 2006


Travis Oliphant wrote:
> Nils Wagner wrote:
>   
>> Arnd Baecker wrote:
>>   
>>     
>>> just to report something positive with
>>> my (almost;-) daily build on 64Bit:
>>>
>>> With '0.5.0.2012' **all** tests pass on 64 Bit
>>> (apart from the well-known ndimage one).
>>>
>>> Best, Arnd
>>>
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>>> Scipy-dev mailing list
>>> Scipy-dev at scipy.net
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>>>   
>>>     
>>>       
>> On 32 bit there is still one failure but I cannot reproduce it on a 64
>> bit system. Why ?
>>   
>>     
>
> I don't know.  I looked at it a bit, but couldn't see anything obvious.
>
> But, since you have access to both systems you are in a great position 
> to figure out why it is failing on 32-bit systems.   Insert some 
> print-statements in the fmin_cobyla code (the calcfc function might be a 
> good place) and compare the outputs on the two systems when you run just 
> that test. 
>
> It would be great if you could help track it down.
>
> -Travis
>
>
>
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>   


Let's start with the example in test_cobyla.py

         function = lambda x: x[0]**2 + abs(x[1])**3
        con1 = lambda x: x[0]**2 + x[1]**2 - 25
        con2 = lambda x: -con1(x)

I guess it is taken from a book on optimization. Is that true ?
A reference would be fine.

    cons     -- a sequence of functions that all must be >=0 (a single
function
                if only 1 constraint)

The first constraint reads

x^2 + y^2 -25 \ge 0

The second constraint is

-x^2-y^2+25 \ge 0   or x^2+y^2 -25 \le 0

Does that mean that we can combine both inequality constraints to one
equality constraint - a circle with radius 5 and center in (x=0,y=0)?

Nils





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