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Re: FindMinimum is not obeying my bounds

  • To: mathgroup at smc.vnet.net
  • Subject: [mg62671] Re: [mg62652] FindMinimum is not obeying my bounds
  • From: Andrzej Kozlowski <akoz at mimuw.edu.pl>
  • Date: Wed, 30 Nov 2005 06:04:23 -0500 (EST)
  • References: <200511300507.AAA00125@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

On 30 Nov 2005, at 14:07, Chris Chiasson wrote:

> Dear MathGroup,
>
> FindMinimum is not obeying my bounds:
>
> In[1]:=
> FindMinimum[(x-1)^2,{x,-80,-100,-70}]
> Out[1]=
> {0.,{x\[Rule]1.}}
>
> Version Number: 5.2.0.0
> Platform: Windows
>
> How does this turn out on your computers?
>
> Regards,
> --
> http://chrischiasson.com/contact/chris_chiasson
>


Yes, there is definitely something funny here, for note the following:


FindMinimum[(x-1)^2,{x,-80,-100,-70}]


{0.,{x->1.}}


FindMinimum[Expand[(x-1)^2],{x,-80,-100,-70}]


The point -70. is at the edge of the search region in coordinate 1and  
the computed search direction points outside the region.

{5041.,{x->-70.}}

I would say this indicates a bug, wouldn't you? (This is with  
Mathematica 5.1 for Mac OS X).

Actually, I think problems with polynomial input and restrictions are  
better done by Minimize:


Minimize[{(x - 1)^2, -100 <= x <= -70}, x]


{5041, {x -> -70}}

Andrzej Kozlowski




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