Desperate due to NMinimize

[toxic topas]

I am working with Mathematica 7. I want to use NMinimize to find the
minimum of a function that is calculated by an external program. It is
called by Run with some arguments and it writes the result into a
file. I then use Import to read the value. Such a situation can be
mimicked by:

dd[x_]:=(Export["test.dat",x^2];Import["test.dat"])[[1, 1]]
NMinimize[dd[x],x]

If you give the function dd a value it returns the result correctly
(and writes a file). But NMinimize does not specify a value for x but
tries to evaluate the expression generally for a global x. I tried
everything that I could possibly think of using HoldAll, Unevaluated,
With[{x=x},], ... Nothing worked.

Is there anybody that can help me?

[Nasser M. Abbasi]

In[1]:= Remove["Global`*"]
dd[x_?NumericQ]:=(Export["test.dat",x^2];Import["test.dat"])[[1,1]]
Chop@NMinimize[dd[x],x]

Out[3]= {0,{x->5.905900171355918*10^-7}}
In[4]:= NMinimize[x^2,x]
Out[4]= {0.,{x->0.}}

--Nasser

[Bob Hanlon]

Restrict dd to numeric arguments

dd[x_?NumericQ] := (
Export["test.dat", x^2];

Import["test.dat"])[[1, 1]]

Bob Hanlon

---- toxic topas <toxic...@googlemail.com> wrote:

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