Re: FindMaximum query
- To: mathgroup at smc.vnet.net
- Subject: [mg85559] Re: FindMaximum query
- From: Daniel Huber <dh at metrohm.ch>
- Date: Wed, 13 Feb 2008 07:25:52 -0500 (EST)
- References: <foudug$m07$1@smc.vnet.net>
Hi Neely,
deine fun like:
fun[x_?NumericQ]
hope this helps, Daniel
E. Neely Atkinson wrote:
> Consider the following function:
>
> fun[x_] :=
> Module[
> {y, sol},
> sol = FindRoot[Sqrt[y] == Abs[x], {y, 0, 0.001}];
> (* AppendTo[list, sol]; *)
> -y /. sol[[1]]
> ]
>
> Then Plot[fun[x], {x, -2, 2}] works fine, but
>
> FindMaximum[fun[x], {x, 1, 1.001}]
>
> fails. If I uncomment the debug line in fun and execute
>
> list = {};
> FindMaximum[fun[x], {x, 1, 1.001}]
>
> Then list contains
>
> {FindRoot[Sqrt[y$21471] == Abs[x], {y$21471, 0, 0.001}]}
>
>
> So, FindRoot fails because x is passed through unevaluated, I think.
> I would appreciate any advice on how to get FindMaximum (or NMaximize)
> to work in this case.
>
> Mathematic 6.0.1.0 x86 32 bit
> Mac OS X 10.4.11
>
> Thanks very much,
>
> E. Neely Atkinson
> Department of Biostatistics
> M. D. Anderson Cancer Center
>
> neely at pdq.net
>