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Re: Minimization problem

  • To: mathgroup at smc.vnet.net
  • Subject: [mg132357] Re: Minimization problem
  • From: Bob Hanlon <hanlonr357 at gmail.com>
  • Date: Wed, 19 Feb 2014 02:01:31 -0500 (EST)
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Presumably there is a problem with your definition of f; however, since you
have not given an example of a simpler function which demonstrates your
problem, I can only guess.


var = {h1, h2, h3, h4};


cons = 0.1 < # <= 1 & /@ var;


f[{h1_?NumericQ, h2_?NumericQ,
    h3_?NumericQ, h4_?NumericQ}] :=
  Abs[-2 h1 + 7 h2 - 3 h3 + 8 h4 + 3];


sol = NMinimize[{f[var], cons}, var]


{1.45916*10^-9, {h1 -> 0.939012, h2 -> 0.1, h3 -> 0.959647, h4 -> 0.132121}}


sol[[1]] == f[var] /. sol[[2]]


True



Bob Hanlon




On Mon, Feb 17, 2014 at 11:04 PM, PAR123 <reiser.paul at gmail.com> wrote:

> I'm trying to minimize f[{h1,h2,h3,h4}] subject to constraints that all
> h's lie between 0.1 and 1. Trying to use NMinimize:
> NMinimize[{f[{h1, h2, h3, h4}], {h1 > 0.1, h1 <= 1.0, h2 > 0.1,
>    h2 <= 1.0, h3 > 0.1, h3 <= 1.0, h4 > 0.1, h4 <= 1.0}}, {h1, h2, h3,
>    h4}]
>
> I keep getting errors that indicate FindMinimum is attempting to call f[]
> with symbolic h's, not numbers. f[] will return a number if the inputs are
> numbers, but if they are symbols, its not going to happen. Is there a
> simple thing I am doing wrong?
>
>




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