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MathGroup Archive 2006

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Re: Possible simple bug in NMaximize

  • To: mathgroup at smc.vnet.net
  • Subject: [mg71061] Re: [mg71040] Possible simple bug in NMaximize
  • From: Andrzej Kozlowski <akoz at mimuw.edu.pl>
  • Date: Wed, 8 Nov 2006 06:11:27 -0500 (EST)
  • References: <200611060752.CAA08685@smc.vnet.net>

On 6 Nov 2006, at 16:52, Nick Grishin wrote:

> (* does not work *)
> func = Hold[NIntegrate[t^3, {t, x, 0}]];
> NMaximize[func, x]
>
> (* works *)
> func = Hold[NIntegrate[t^3, {t, 0, x}]];
> NMinimize[func, x]
>
> $Version
> 5.2 for Microsoft Windows (June 20, 2005)
>

A bug in NMaximize? Why? It behaves exactly as it should do with this  
kind of input.  The problem is with MMinimize, because you when you  
give it nonsensical input it actually produces output, which  
unfortunately (by sheer accident),  looks as if it might be right.  
But it is nonssense nonetheless (nonsense in - > nonsense out)  
nonsensical, and  to convince you of it I will slightly change your  
input:

func = Hold[NIntegrate[t^3, {t, 10, x}]];


NMinimize[func, x]


{-2500.0000000000005, {x -> -0.0002833987269403981}}

Now, does this look like it "works"?

Andrzej Kozlowski
  


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