
Re: keep special functions unexpanded
Posted:
Jul 21, 2013 4:14 AM


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? > >

