[SciPy-user] Generating tuples and lists connected with optimize.fmin_l_bfgs_b(func, guess, bounds=bounds, iprint=-1)

Christian Kristukat ckkart at hoc.net
Fri Jul 1 03:14:54 CDT 2005


Nils Wagner wrote:
> Nils Wagner wrote:
> 
>> Hi all,
>>
>> Sorry for this inquiry but how can I initialize the list "bounds" and 
>> the tuple "guess" more efficiently ?
>> The entries in bounds are identical for each design variable, while 
>> the initial guess consists of two different values.
>> So how can I benefit from this pattern in building "bounds" and 
>> "guess" for 2n design variables ?
>>
>> bounds = [(0.0,2.0), (0.0,2.0), (0.0,2.0), (0.0,2.0), (0.0,2.0), 
>> (0.0,2.0)]
>> guess = 2.0,2.0,2.0,1.0,1.0,1.0
>>
>> A small example would be appreciated.
>>
>> Thanks in advance
>>                                         Nils
>>
>> _______________________________________________
>> SciPy-user mailing list
>> SciPy-user at scipy.net
>> http://www.scipy.net/mailman/listinfo/scipy-user
> 
> 
> Is there a better way for building bounds ?
> 
> bounds=[]
> for i in arange(0,2*n):
>  bounds = bounds + [(0.0,2.0)]

bounds = [(0.0,2.0)]*n

This works with python lists, not with numeric arrays.

btw: I'm using fmin_tnc which is another constrained minimizer and I found that 
it is much faster than bfgs for large problems.

Regards, Christian



More information about the SciPy-user mailing list