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Warning Message wrt NMinimize function

• To: mathgroup at smc.vnet.net
• Subject: [mg69731] Warning Message wrt NMinimize function
• From: "John Adeosun" <jtadeosun at yahoo.com>
• Date: Thu, 21 Sep 2006 07:32:17 -0400 (EDT)
• Organization: Stevens Institute of Technology (stevens-tech.edu)

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.

• Follow-Ups:
  • Re: Warning Message wrt NMinimize function
    • From: "Chris Chiasson" <chris@chiasson.name>