Re: Functions inside modules with external definitions

*To*: mathgroup at smc.vnet.net*Subject*: [mg96505] Re: Functions inside modules with external definitions*From*: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>*Date*: Sun, 15 Feb 2009 03:19:55 -0500 (EST)*References*: <gn5ugm$h02$1@smc.vnet.net>

Hi, and my question is "Why do you use Module[] ?" expression = a x^c + b y^(1 - c); mx = Block[{f, expression = expression}, f[x_: x, y_: y][a_ : a, b_: b, c_: c] := Evaluate@expression; f[k1, k2][.2, .3, .4] ] work as expected. Regards Jens E. Martin-Serrano wrote: > Hi, > > > > Please review the following and see weather my question has and deserves an > answer. It is a about defining functions local to modules but using external > definitions of the right hand side of the local function and passed as > parameters to the module. > > > > > > expression = a x ^c + b y ^(1-c) (* or whatever expression *) > > > > Clear[f]; > > > > f[x_: x,y_: y][a_: a,b_: b,c_: c]:=Evaluate@expression > > > > ?f > > f[k1,k2][.2,.3,.4] > > > > (* Functions inside modules where the RHS of the function has been assigned > to a variable *) > > (* first form works as I expected, but uses an extrenal definition for a > local function (the name is local) *) > > > > m1= > > Module[{f}, > > f[x_: x,y_: y][a_ :a,b_: b,c_: c]:=Evaluate@expression; > > f[k1,k2][.2,.3,.4] > > ] > > > > (* second form. I expected it worked as the one above but it does not; the > expression formed outside is assigned to a local variable with the same name > *) > > > > m2 = > > Module[{f, expression = expression}, > > f[x_: x, y_: y][a_ :a,b_: b,c_: c]:=Evaluate@expression; > > f[k1,k2][.2,.3,.4] > > ] > > > > (* third form. I expected it worked as the first one above but it does not; > the expression is assigned directly to a local variable *) > > > > m3 = > > Module[{f,expression = a x ^c + b y ^(1-c)}, > > f[x_: x,y_: y][a_ :a,b_: b,c_: c]:=Evaluate@expression; > > f[k1,k2][.2,.3,.4] > > ] > > > > (* fourth form. I expected it worked as the first one above but it does not; > the expression is assigned within the body of the module o a local variable > *) > > > > m4 = > > Module[{f,expr}, > > expr =expression; > > f[x_: x,y_: y][a_ :a,b_: b,c_: c]:=Evaluate@expr; > > f[k1,k2][.2,.3,.4] > > ] > > > > (* My question is how to construct a function inside a module in manner > similar to the following *) > > > > expression = a x ^c + b y ^(1-c); > > mx = > > Module[{f,expression = expression}, > > f[x_: x,y_: y][a_ :a,b_: b,c_: c]:=Evaluate@expression; > > f[k1,k2][.2,.3,.4] > > ] > > > > (* and working as the following works *) > > > > m1= > > Module[{f}, > > f[x_: x,y_: y][a_ :a,b_: b,c_: c]:=Evaluate@expression; > > f[k1,k2][.2,.3,.4] > > ] > > > > Many thanks > > > > > > E. martin-Serrano > >

**Follow-Ups**:**Re: Re: Functions inside modules with external definitions***From:*"E. Martin-Serrano" <eMartinSerrano@telefonica.net>