Running xppaut in Windows

Running xppaut in Windows is sometimes tricky. My new book on nonlinear dynamics gives brief instructions on installing the Cygwin X server and xppaut in Windows, but I’ve often had trouble getting xppaut to play nice with Cygwin/X. After playing around with today, I think I’ve come up with a set of instructions that will work every time. And of course I expect to be proven wrong almost immediately… However, I’m still happy to share what I’ve learned.

What I’m trying to achieve here is a low-fuss installation that will let you run xppaut from the command line. Because I’m much more familiar with Unix shell programming than with DOS batch files, my solution involves the former. You’re going to be installing Cygwin anyway, so we might as well take advantage of its full power.

I will be leaving you to read the documentation for the details of how to accomplish some of the tasks below. None of them exceed the intelligence of an average person, and links to the documentation are given. Here are the steps:

  1. Install Cygwin. In the package installer, select the latest versions of xinit, xset and xhost for installation.
  2. Get the xppaut for Windows zip file. Unzip the package and put the xppall folder that it contains somewhere sensible. Bard Ermentrout recommends the top level of the boot (C:) drive, but I don’t think that’s necessary.
  3. Add the xppall folder’s location to your PATH environment variable. If you put this folder at the top level of your C: drive, you would add C:\xppall to your PATH variable.
  4. Create the following file using a file editor (Windows Notepad, or a Unix editor like vi or emacs; emacs must be installed first with the Cygwin installer if you want to use that) in the xppall folder that you just installed:

# Script to run xppaut in Cygwin using the Cygwin/X server.
# You can call this script xpp, then invoke it on the command line as you would xppaut.

# Start X server if one isn't already running.
export DISPLAY=
if ! xset q >&/dev/null; then
    startxwin -- -listen tcp >&/dev/null &
    # The following 5-second pause will slow down startup, but ensures that the
    # Xwindows server is up before trying to call xhost, which otherwise may hang.
    sleep 5
    xhost + >&/dev/null

# Run xppaut, passing through any command-line parameters supplied to this script.
xppaut $1 $2 $3 $4 $5

I recommend that you save this file to into the xppall folder, using the file name xpp. Now open a Cygwin terminal and issue the following commands (assuming you put xppall at the top level of the C: drive):

cd /cygdrive/c/xppall
chmod u+x xpp

This will make this file executable. (It may already have been, but you might as well make sure.) If all went well, you should now be able to run xppaut by typing ‘xpp file.ode’ in a terminal window where, obviously, ‘file.ode’ would be replaced by the name of an ode file in the current working directory. There are a bunch of ode files in xppall/ode. I usually test a new installation of xppaut using lorenz.ode.

Note that this will work provided you do not start the XWin Server from the Start menu.

By all means let me know if you try this and run into problems. Within reason, I will try to help.