[SciPy-user] Questions about scipy.optimize.fmin_cobyla
fdu.xiaojf@gmai...
fdu.xiaojf@gmai...
Mon Jul 16 08:25:42 CDT 2007
Hi dmitrey,
Thank you so much for your kindness!
dmitrey wrote:
> so if you have only x >= 0 constraints, it's better to use tnc or
> openopt lincher than fmin_cobyla
Unfortunately, the function I want to minimize still has equality
constraints. The reason why I chose cobyla is that cobyla can handle
inequality and equality constraints, and it doesn't require derivate
information.
>
> if you have to use cobyla anyway, try this:
>
>
> a = []
> for i in range(5):
> a.append(lambda x: x[i]**2)
> x = [1,2,3,4,5]
> for i in range(5):
> print a[i](x)
>
> 1
> 4
> 9
> 16
> 25
The constrain functions are called by fmin_cobyla, so I couldn't make
sure "for i ...." are used when the constrain functions are called.
In your example, if I use "for j in range(5): print a[j](x)", it will
not work as expected.
>
> If you will replace xi by exp(xi), don't forget to replace lb[i]=0 by
> lb[i]=1
I'm trying this.
>
> HTH, d
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