Re: Desperate due to NMinimize

*To*: mathgroup at smc.vnet.net*Subject*: [mg114653] Re: Desperate due to NMinimize*From*: "Nasser M. Abbasi" <nma at 12000.org>*Date*: Sun, 12 Dec 2010 05:40:27 -0500 (EST)*References*: <idv75v$t29$1@smc.vnet.net>*Reply-to*: nma at 12000.org

On 12/10/2010 10:53 PM, toxic topas wrote: > 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? > 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