Program to draw slopes

This program will draw a mesh of slopes for an autonomous system of two first order ordinary differential equations in two unknowns of the form

               dx                    dy
               -- = fx(x,y)          -- = fy(x,y)
               dt                    dt

Any scalar first order ordinary differential equation for y(x) can be brought in this form by simply defining t to be x.

To use the program:

Create a folder 'aim' in the 'private' folder on your unix disk.
Copy the following files to that folder, by right-clicking and then saving the link targets:
Edit the files fx.f and fy.f and put in the functions describing the time derivatives of x, respectively y, for your particular problem.
Edit file slopes.ind and set the limits between which to plot x and y.
Log onto the unix system, say dingo.eng.famu.fsu.edu, using something like Putty, X-Win32, MiX, or similar.
Move to the folder with the saved files using 'cd ~/private/aim'.
Enter 'make'. If there are no errors, a plot file 'dump.ps' will be created. This file is postscript; it can be printed on a postscript-capable printer. The last time I looked, that included the lab printers. Alternatively, you can acquire the free 'ghostview' and 'ghostscript' software and print the file 'dump.ps' to any printer by loading it into ghostview.