Re: Warning Message wrt NMinimize function
- To: mathgroup at smc.vnet.net
- Subject: [mg69762] Re: Warning Message wrt NMinimize function
- From: p-valko at tamu.edu
- Date: Fri, 22 Sep 2006 01:04:42 -0400 (EDT)
- References: <eeu01h$b83$1@smc.vnet.net>
As it is written right now, you are minimizing a list that consists of two elements, each of them being a list itself. NMinimize really does not know what to do with such an object. (Very often in Mathematica - and in any software - the error messages are difficult to understand because they are logical only within a given context, but the user misses the context itself, not the particulars within the context. I think the next generation of softwares will have some AI built-in to recognize the real root of the misunderstanding and will offer more help. Today softwares, like Mathematica, still look like a bit autistic persons, but soon they will have more empathy for the user. ) John Adeosun wrote: > 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.