Re: FourierTransform problem

*To*: mathgroup at smc.vnet.net*Subject*: [mg35100] Re: [mg35081] FourierTransform problem*From*: BobHanlon at aol.com*Date*: Tue, 25 Jun 2002 03:39:41 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

In a message dated 6/24/02 4:58:37 AM, dturner at faulkner.edu writes: >I am using Mathematica for Students 3.0.1 with Windows 98. When I execute >the following code, I get the error messages below: > >In[1]:= ><<Calculus`FourierTransform` > >In[2]:= >Clear[fx, fw, a] > >In[3]:= >a:=1 > >In[4]:= >fx[x_]:=Exp[-Abs[x*a]] > >In[5]:= >fw[w_]:=InverseFourierTransform[fx[x], x, w] > >In[6]:= >Plot[fw[w], {w, -5*a,5*a}] > >Plot::plnr : fw[w] is not a machine-size real number at w = -5.. >Plot::plnr : fw[w] is not a machine-size real number at w = -4.59433.. >Plot::plnr : fw[w] is not a machine-size real number at w = -4.15191.. >General:: stop : Further output of Plot::plnr will be suppressed during >this >calculation. > >Does anyone know where I might obtain a corrected FourierTransform.m package >for Mathematica 3.0.1? My copy is dated 7/21/97. I contacted Wolfram >about >this matter. However, they told me they no longer support version 3.0. > I >appreciate any help you may provide. > Your example works fine with version 4; however, it would be much faster and might work with your version if you use Evaluate in the RHS of the definition of fw. $Version 4.1 for Mac OS X (November 5, 2001) <<Calculus`FourierTransform` Clear[fx, fw, a] ; a=1; fx[x_]:=Exp[-Abs[x*a]]; fw[w_]:=Evaluate[InverseFourierTransform[fx[x], x, w]]; Plot[fw[w], {w, -5*a,5*a}]; Bob Hanlon Chantilly, VA USA