Date: Jul 21, 2013 4:14 AM
Author: Bob Hanlon
Subject: Re: keep special functions unexpanded

t = Table[

{ChebyshevT[ToString[i], x], ChebyshevT[i, x]},

{i, 0, 2}]

{{ChebyshevT["0", x], 1},

{ChebyshevT["1", x], x},

{ChebyshevT["2", x], -1 + 2*x^2}}

t /. i_String :> ToExpression[i]

{{1, 1}, {x, x}, {-1 + 2*x^2, -1 + 2*x^2}}

Bob Hanlon

On Sat, Jul 20, 2013 at 5:58 AM, metrologuy <takacs@bnl.gov> wrote:

> I am trying to create a list of ChebyshevT[n,x] polynomials of different

> orders to use as basis functions in a fitting routine. I want to keep the

> list in the form that explicitly shows the order number. For example, I

> want the list for order n=2 to look like this:

> basislist={ChebyshevT[0,x],ChebyshevT[1,x],ChebyshevT[2,x]}.

> If I use Table to generate the list, I get each function expanded into a

> polynomial in x:

>

> In[1]:= Table[ChebyshevT[i,x],{i,0,2}]

>

> Out[1]= {1,x,-1+2 x^2}

>

> How can I prevent the function from displaying the expanded form for each

> value of n? If I use the unexpanded form in the Fit[] function, it works

> just fine. But I lose the visual connection to the explicit order number in

> the input form of the function. Any suggestions how to keep the "n" visible?

>

>