Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
2006
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*November
*December
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 2006

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: Possible simple bug in NMaximize

  • To: mathgroup at smc.vnet.net
  • Subject: [mg71090] Re: [mg71040] Possible simple bug in NMaximize
  • From: Nick Grishin <grishin at chop.swmed.edu>
  • Date: Wed, 8 Nov 2006 06:14:23 -0500 (EST)
  • References: <200611060752.CAA08685@smc.vnet.net> <385666A3-8452-4267-9A16-51F52DC79904@mimuw.edu.pl> <AD156707-E97C-4D2A-8251-A2FD989FC235@mimuw.edu.pl>

> On 6 Nov 2006, at 19:05, Andrzej Kozlowski wrote:
>
>> 
>> 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
>
>
> I have to admit that my example was pointless; it does also "work" just as 
> much as your example works, although it should not. I agree that seeing this

This I understand.
n


  • Prev by Date: Re: Possible simple bug in NMaximize
  • Next by Date: Re: Evaluating integral with varying upper limit?
  • Previous by thread: Re: Possible simple bug in NMaximize
  • Next by thread: Re: Possible simple bug in NMaximize