Re: Function of several variables
- To: mathgroup at smc.vnet.net
- Subject: [mg72135] Re: Function of several variables
- From: dh <dh at metrohm.ch>
- Date: Wed, 13 Dec 2006 06:39:37 -0500 (EST)
- References: <eljaik$7dv$1@smc.vnet.net>
Hi Troy,
in Mathematica you have the possibility to treat arguments "block-wise"
instead of piecewise. Consider e.g.:
fun[x__] := 1/(Plus[x]) (note the 2 underscores)
here we specified that we have 1 or more arguments. We could now call
fun like: fun[1],fun[1,2],fun[1,2,3] e.t.c.
Daniel
tlhiv wrote:
> I have created a list of variables that I would like to make a function
> in terms of by
>
> M = 4;
> X = Table[Subscript[x, i], {i, 1, M}]
>
> Now I would like to make a function f that is a function of each of
> these M variables. If I were manually create this function without
> taking advantage of iterators, I would do something like
>
> f[Subscript[x,1]_,Subscript[x,2]_,Subscript[x,3]_,Subscript[x,4]_] =
> 1/(Subscript[x,1]+Subscript[x,2]+Subscript[x,3]+Subscript[x,4])
>
> However, my plan is to significantly increase M, and therefore I don't
> want to have to manually define f in this way. I would like to define
> it in terms of the elements of X and use the Sum in the function
> definition. In the end I'm going to be solving an optimization problem
> where I try to find the "optimal" choice for these elements of X. Can
> someone offer a method for accomplishing this function definition?
>
> Thanks,
>
> --
> Troy Henderson
> Assistant Professor
> Department of Mathematical Sciences
> United States Military Academy
> http://www.tlhiv.org
>