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MathGroup Archive 2006

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Warning Message wrt NMinimize function (Omitted Info. Added)

  • To: mathgroup at smc.vnet.net
  • Subject: [mg69799] Warning Message wrt NMinimize function (Omitted Info. Added)
  • From: John Adeosun <jtadeosun at yahoo.com>
  • Date: Sat, 23 Sep 2006 04:45:01 -0400 (EDT)
  • References: <eeu01h$b83$1@smc.vnet.net> <eevsse$h1a$1@smc.vnet.net>

Hi,

Thanks for your responses. Thanks Jens for bringing to my attention what I 
unintentionally omitted in the statement of the problem. That is, I forgot 
to mention that each element in the list "bb" is a non-linear expression 
each of which is a function of y (a parameter I'm trying to estimate). 
Meanwhile, the list "aa" , of equal length as list "bb", comprises elements 
with real numbers.

 Any help or further insight?

Thanks.

John.



----- Original Message ----- 
From: "Jens-Peer Kuska" <kuska at informatik.uni-leipzig.de>
To: mathgroup at smc.vnet.net
Subject: [mg69799] Re: Warning Message wrt NMinimize function


> Hi,
>
> regardless of the fact that your input is
> nonsense, because
> your objective function does not depend on y at
> all
> With[{n = 4},
>  aa = Table[Random[], {n}];
>  bb = Table[Random[], {n}];
>  NMinimize[{Plus @@ Table[(aa[[i]] - bb[[i]])^2,
> {i, n}], {y > 0}}, y,
>    Method -> "DifferentialEvolution"]
> ]
>
> work fine for me and I assume, that you hide some
> facts to prevent
> us from answer your question.
>
> Regards
>  Jens
>
> "John Adeosun" <jtadeosun at yahoo.com> schrieb im
> Newsbeitrag news:eeu01h$b83$1 at smc.vnet.net...
> | Hello Everyone,
> |
> | I want to use NMinimize to solve an optimization
> problem. In essence, I'm
> | trying to numerically minimize the "sum of a
> square of errors" for two
> | lists, aa and bb (earlier generated lists of n
> elements or points), using
> | the below syntax:
> |
> | NMinimize[{Plus @@ Table[(aa[[i]] - bb[[i]])^2,
> {i, n}], {y> 0}}, y,
> | Method -> "DifferentialEvolution"]
> | This does not yield the intended result of, say,
> {minimumvalue, y->10.012}.
> | I have been getting an expression (unevaluated
> "result" ) with a warning
> | message such as:
> |
> | NMinimize::nnum : The function value {336.381}
> is not a number at {y}=
> | {0.063703}. More...
> |
> | I then clicked on 'More' for help. I got the
> below message from the help
> | browser:
> |
> | "General::nnum
> |
> | function::nnum: The function value `3` is not a
> number at `2` = `1`.
> |
> | Notes for this message have not yet been added."
> |
> | Has anyone experienced this before? Is anything
> wrong with my syntax above?
> |
> | Thanks in advance for your useful insight.
> |
> | John.
> |
> |
> |
> |
> |
> |
>
> 


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