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. > | > | > | > | > | > | > >