[Q] Programming & "Not Floating Point Number" Error

*Subject*: [mg3133] [Q] Programming & "Not Floating Point Number" Error*From*: ntd at cs.duke.edu (Noel T. Doromal)*Date*: 7 Feb 1996 09:07:56 -0600*Approved*: usenet@wri.com*Distribution*: local*Newsgroups*: wri.mathgroup*Organization*: Duke University*Sender*: daemon at wri.com

Hello out there! This is my first time on this group, so I apologize for breaking any netiquette rules. I have a Mma question that I hope someone out there can help me with. I recently started using Mma for a class and have had a hard time "programming" with it. Here is the script/program that i wrote: -- epsilon = .01 gamma = 7 dt = .125 stim = 0 y0 = -.5 w0 = 0.0 For[i=0, i<50, i++, f = y0 * (1 - y0 *y0); v = y0 + (f - w0) * dt; w = w0 +(epsilon*(gamma*y0 - w0)) * dt; vee[i] = v; doubleu[i] = w; y0 = v; w0 = w; ] ListPlot[{vee,doubleu}] --- First question: Are there examples of Mma programs out there that are longer than a line or two? (Or was mathematica not really made for programming?) I bought the book and can't find any in there. (It describes the control structures: do, if, for... but then gives one line examples only) Second: In the script above I'm essentially calculating a bunch of points that I want to plot (V vs. W - I had to use "vee" and "doubleu" to get it to work). The only way I could figure to do it was to store the numbers in a list and then use ListPlot[] but I can't get it right. I keep getting: -- Graphics::gptn: Coordinate vee in {1, vee} is not a floating-point number. Graphics::gptn: Coordinate doubleu in {2, doubleu} is not a floating-point number. -- What am I doing wrong? Thanks for the help, Noel