       How to use NMinimize with a numerical function

• To: mathgroup at smc.vnet.net
• Subject: [mg65362] How to use NMinimize with a numerical function
• From: Marco Gabiccini <m.gabiccini at ing.unipi.it>
• Date: Tue, 28 Mar 2006 04:05:33 -0500 (EST)
• Sender: owner-wri-mathgroup at wolfram.com

```Hi all,

I wanted to test NMinimize[] with a numerical function whose return value
is the result of another NMinimize.
I defined the intersection with the abscissa of the parabola y=ax^2+bx+c as
f[a,b,c]
and I want to find one set of values {a,b,c} for which that intersection is
reached at x=-2.

I defined

f[a_, b_, c_] :=
Module[{x}, NMinimize[{(a x^2 + b x + c)^2}, x][[2, 1, 2]]]

and I would like to find that particular value of {a,b,c} for which
f[a,b,c]=-2, that is why I call

FindMinimum[(f[r, s, t] + 2.0)^2, {{r, -5, 5}, {s, -5, 5}, {t, -5, 5}}]

but I get this error message
1760692.jpg

obtain this - moderator]

It seems that the latter FindMinimum[] keeps the r,s,t unevaluated when
calling f in the first FindMinimum. Is there a way to switch the order of
evaluation?

Can anybody help me?

Marco

```

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