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Re: Question on looping FindRoot

  • To: mathgroup at smc.vnet.net
  • Subject: [mg86702] Re: Question on looping FindRoot
  • From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
  • Date: Wed, 19 Mar 2008 05:22:37 -0500 (EST)
  • Organization: Uni Leipzig
  • References: <fro35c$i3b$1@smc.vnet.net>
  • Reply-to: kuska at informatik.uni-leipzig.de

Hi,

and you know the difference between Set[] "=" and
Equal[] "==" ?

Regards
   Jens

PS: Using % and %% .. is not a good idea, because
it is used in the command line variant of the Mathematica
kernel but in a notebook interface it will cause many
mystic errors.

Alessandro Tavoni wrote:
> Hello,
> 
> this is probably due to my being relatively new to Mathematica,
> but I cannot succesfully execute a loop with FindRoot.
> when I give the following input (I have converted it to input form):
> 
> 
> ClearSystemCache[]
> ratio = 1
> \[Lambda] = 1.4
> k = 1
> Overscript[U1, DifR] =
>   Table[14 - 6*\[Beta]1, {\[Beta]1, 0, 0.5/ratio, 0.5/ratio/1000}];
> Overscript[U1, UifR] =
>   Table[4 - 18*\[Alpha]1, {\[Alpha]1, 0, 0.5, 0.0005}];
> Overscript[U1, UifL] =
>   Table[10 - 2*\[Alpha]1, {\[Alpha]1, 0, 0.5, 0.0005}];
> Overscript[U1, DifL] =
>   Table[9*(\[Alpha]1 + 1)^0, {\[Alpha]1, 0, 0.5, 0.0005}];
> Overscript[U2, LifD] =
>   Table[9*(\[Alpha]1 + 1)^0, {\[Alpha]1, 0, 0.5, 0.0005}];
> Overscript[U2, RifD] =
>   Table[8 - 6*\[Alpha]2, {\[Alpha]2, 0, 0.5, 0.0005}];
> Overscript[U2, RifU] =
>   Table[22 - 18*\[Beta]2, {\[Beta]2, 0, 0.5/ratio, 0.5/ratio/1000}];
> Overscript[U2, LifU] =
>   Table[12 - 2*\[Beta]2, {\[Beta]2, 0, 0.5/ratio, 0.5/ratio/1000}];
> For[k = 1, k < 5, k++,
>  eq1 = Pu == (Exp[\[Lambda]*(Overscript[U1, UifL][[k]]*Ql +
>            Overscript[U1, UifR][[k]]*(1 - Ql))]/
>               (Exp[\[Lambda]*(Overscript[U1, UifL][[k]]*Ql +
>              Overscript[U1, UifR][[k]]*(1 - Ql))] +
> 
>          Exp[\[Lambda]*(Overscript[U1, DifL][[k]]*Ql +
>              Overscript[U1, DifR][[k]]*(1 - Ql))]))*eq2 =
>        Ql == (Exp[\[Lambda]*(Overscript[U2, LifU][[k]]*Pu +
>             Overscript[U2, LifD][[k]]*(1 - Pu))]/
>                 (Exp[\[Lambda]*(Overscript[U2, LifU][[k]]*Pu +
>               Overscript[U2, LifD][[k]]*(1 - Pu))] +
> 
>           Exp[\[Lambda]*(Overscript[U2, RifU][[k]]*Pu +
>               Overscript[U2, RifD][[k]]*(1 - Pu))]))*Prob =
>     FindRoot[{eq1, eq2}, {Pu, 0}, {Ql, 0}]*ProbUp[[k ;; All]] =
>            %[[1]]*ProbLf[[k ;; All]] = %%[[2]]]
> 
> 
> I'm told Symbol::argx: Symbol called with 0 arguments; 1 argument is
> expected.
> and:                  Set::write: Tag Times in
> 
> Thank you so much in advance,
> 
> Alessandro
> --
> Alessandro Tavoni
> Ph.D. candidate
> Advanced Scool of Economics, University of Venice "C=E0 Foscari"
> http://venus.unive.it/alessandro.tavoni


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