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Welcome to XPP Lab

XPP Lab is a workbench for dynamical systems: you write the equations, then simulate them, explore their phase plane and compute bifurcation diagrams with AUTO. Under the hood it runs XPPAUT 8.0, the program by Bard Ermentrout that a generation of scientists has used, with its own numerical code. Any XPPAUT .ode file works here as it is.

A first look in one minute

  1. Open the Morris-Lecar neuron model. It is a classic two-variable model of a nerve cell.
  2. Run it (run). The Time Series tab shows V and W over time.
  3. Open the Phase Plane tab and draw the nullclines (nullclines). Click anywhere in the plot to start a new trajectory from that point.
  4. In Workspace > Parameters, drag the iapp slider (the injected current). The solution updates as you drag.
  5. Find the equilibrium (eq) near the current state. The command window reports its stability and eigenvalues.

The windows

Window What it is for
Models Example models and recent files. Hover a name for a description.
Workspace Parameters (with sliders), initial values, numerics, parameter sets.
Editor The .ode file. Press Ctrl+Enter to apply changes.
Time Series Variables against time.
Phase Plane One variable against another, with nullclines and flow.
Bifurcation AUTO: follow equilibria and periodic orbits as a parameter varies.
Command Window A log of what happened, and a command line.
Help This manual. Press F1 any time.

Every window can be dragged, docked, stacked in tabs or closed. To get the original arrangement back, use View > Reset window layout.

Saving your work

  • Figures: every plot has an Export... button. Choose PNG for an image exactly as shown, or SVG for a vector figure that stays sharp at any size, for papers and posters.
  • Data: File > Export data as CSV saves the last run for spreadsheets, MATLAB or Python.
  • Models: File > Save (Ctrl+S) writes the .ode file. Parameters you changed in the Workspace are not written into the file; put values you want to keep in the file, or in a named set. The examples that come with XPP Lab stay as they are: when you save an edited example, your version goes to a copy in the folder XPP Lab in your Documents, and you go on working with the copy.

Where to go next

Tip: if you know XPPAUT's keyboard commands, they still work: I G integrates, N N draws nullclines, S G finds an equilibrium. See Commands and keyboard shortcuts.