Re: Function of several variables

*To*: mathgroup at smc.vnet.net*Subject*: [mg72131] Re: [mg72077] Function of several variables*From*: "Josef Otta" <josef.otta at gmail.com>*Date*: Wed, 13 Dec 2006 06:39:26 -0500 (EST)*References*: <200612110954.EAA07090@smc.vnet.net>*Reply-to*: josef.otta at mensa.cz

Try to do this: X[m_] := Table[Subscript[x,i], {i, 1, m}]; f[r_?ListQ] := (1/#) &@(Plus @@ r); f[X[100]] I hope that it can solve your problem, Josef Otta 2006/12/11, tlhiv <thenders at gmail.com >: > > 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 > >

**References**:**Function of several variables***From:*"tlhiv" <thenders@gmail.com>