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Re: typing starting values in FindMinimum

  • To: mathgroup at smc.vnet.net
  • Subject: [mg15497] Re: typing starting values in FindMinimum
  • From: "Dale Horton" <daleh>
  • Date: Mon, 18 Jan 1999 04:22:43 -0500
  • Organization: Wolfram Research, Inc.
  • References: <77f0j5$m17@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

For 100 variables all starting at .5

theta=Table[ToExpression["l"<>ToString[i]],{i,100}];
start=Table[.5,{100}]
startval=Transpose[{theta,start}]

Apply[FindMinimum[Apply[Plus,e^2],#,Method->Newton,Gradient->j]&,
    startval]

-Dale

Albert Maydeu-Olivares wrote in message <77f0j5$m17 at smc.vnet.net>...
>Hi everyone,
>
>Consider the use of FindMinimum when the function to be minimized
>depends on several variables
>
>In[1]:=
>j={{l2,l1,0},{l3,0,l1},{0,l3,l2}};
>e={0.56 -l1 l2,0.48 -l1 l3, 0.42 -l2 l3};
>FindMinimum[Apply[Plus,e^2],{l1,.5},{l2,.5},{l3,.5},Method->Newton,
>Gradient->j]
>
>Out[1]=
>{8.68919*^-23, {l1->.8, l2->.7, l3->.6}}
>
>Does anyone know to avoid having to type in all the variables names and
>starting values?
>I have some problems with 100 variables!
>
>Of course I can construct
>
>In[3]:=
>theta={l1,l2,l3};
>start ={0.5,0.5,0.5};
>startval=Transpose[{theta,start}]
>
>Out[3]:=
>{{l1,0.5},{l2,0.5},{l3,0.5}}
>
>but that is not what FindMinimum is expecting.
>
>--
>
>Albert Maydeu-Olivares Tel. +34 3 4021079 ext. 3099 Faculty of
>Psychology Fax. +34 3 4021362 University of Barcelona E-Mail:
>amaydeu at tinet.fut.es Passeig de la Vall d'Hebron, 171.
>08035 - Barcelona (Spain)
>
>



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