Re: Two successive FindMinimum -> Bug?

*To*: mathgroup at smc.vnet.net*Subject*: [mg74329] Re: [mg74312] Two successive FindMinimum -> Bug?*From*: Bob Hanlon <hanlonr at cox.net>*Date*: Mon, 19 Mar 2007 01:56:44 -0500 (EST)*Reply-to*: hanlonr at cox.net

fxt[x_,t_]=(x^2-t)^2; Reduce[fxt[x,t]==0,t] t == x^2 tminx should be restricted to numeric arguments tminx[x_?NumericQ]:=t/.FindMinimum[fxt[x,t],{t,1}][[2]]; tminabs=FindMinimum[tminx[x],{x,1}] {0., {x -> 7.450580485901526*^-9}} Bob Hanlon ---- Dmitry Garanin <dgaranin at yahoo.com> wrote: > Hi All, > > I am trying to solve a problem that requires application of FindMinimum (or similar rutines two times and it does not work. Here is a simplified example: > > > fxt[x_,t_]=(x^2-t)^2 (* Searching for a minimal t for which fxt turns to zero *) > tminx[x_]:=t/.FindMinimum[fxt[x,t],{t,1}][[2]] (* Finding the minimizing t for a given x *) > tminabs=FindMinimum[tminx[x],{x,1}] (* Minimizing this t with respect to x. The result should be tminabs=0 at x=0 *) > > The last command here does not work since, evidently tminx[x] (that is x^2 for us humans) is not treated as a regular function. > > Is there a bug here or I am doing something wrong?? > > Help is appreciated. > > > http://profiles.yahoo.com/dgaranin >