Re: keep special functions unexpanded

*To*: mathgroup at smc.vnet.net*Subject*: [mg131415] Re: keep special functions unexpanded*From*: Bob Hanlon <hanlonr357 at gmail.com>*Date*: Sun, 21 Jul 2013 04:23:37 -0400 (EDT)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*Delivered-to*: l-mathgroup@wolfram.com*Delivered-to*: mathgroup-outx@smc.vnet.net*Delivered-to*: mathgroup-newsendx@smc.vnet.net*References*: <20130720095853.F16356A05@smc.vnet.net>

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 at 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? > >

**References**:**keep special functions unexpanded***From:*metrologuy <takacs@bnl.gov>