Install Separatrix on Linux

Download

Free and open source, MIT license

Opens the releases page on GitHub.

64-bit Intel or AMD, distributions from 2022 on

AppImage One file that runs without installing, on most distributions.
Debian package (.deb) Ubuntu, Debian, Linux Mint and Pop!_OS.
RPM package (.rpm) Fedora, openSUSE and other RPM distributions.

SHA256SUMS.txt lists the SHA-256 checksum of every file. · All releases

This guide takes you from the download to your first project. You need a 64-bit Intel or AMD PC with Ubuntu 22.04 or newer, or another distribution from 2022 or later. Separatrix needs no internet connection after you install it.

Choose a file

Go to the Separatrix releases page and look under Assets. Linux has three files. Pick one.

File	Use it when
`Separatrix_1.0.1_linux_x86_64.AppImage`	You want one file that runs without installing anything. It works on most distributions and can update itself.
`Separatrix_1.0.1_linux_amd64.deb`	You use Ubuntu, Debian, Linux Mint or Pop!_OS and want Separatrix in your app menu.
`Separatrix_1.0.1_linux_x86_64.rpm`	You use Fedora, openSUSE or another RPM distribution and want Separatrix in your app menu.

Download SHA256SUMS.txt too, and save it in the same folder as your file. The names on this page are for version 1.0.1. A newer release has its own number in each name.

Check the download

SHA256SUMS.txt lists the SHA-256 checksum of every file in the release. If your file's checksum matches, the download is complete and is the file that was published.

Open a terminal in the folder that holds the download, usually ~/Downloads:
```
cd ~/Downloads
```

Run this command:

sha256sum -c SHA256SUMS.txt --ignore-missing

Check that the line for your file ends in OK, for example Separatrix_1.0.1_linux_x86_64.AppImage: OK.

If the line ends in FAILED, delete the file and download it again. Do not open a file that fails the check.

Install it

Follow the section for the file you chose.

AppImage

Make the file executable:
```
chmod +x Separatrix_1.0.1_linux_x86_64.AppImage
```
You can do the same in the Files app instead. Right-click the file, click Properties, and turn on Executable as Program (on Ubuntu 22.04, open the Permissions tab and select Allow executing file as program).
Run it:
```
./Separatrix_1.0.1_linux_x86_64.AppImage
```
You can also double-click it in the Files app.

The AppImage needs FUSE, which most desktop installs already have. You do not need libfuse2 or libfuse2t64. If nothing opens and the terminal says No suitable fusermount binary found, install FUSE and run the file again:

On Ubuntu or Debian: sudo apt install fuse3
On Fedora: sudo dnf install fuse3

If you cannot install packages, run the AppImage this way instead. It unpacks itself to a temporary folder each time, so it starts more slowly.

./Separatrix_1.0.1_linux_x86_64.AppImage --appimage-extract-and-run

Keep the AppImage somewhere permanent, such as ~/Applications, before you start using it. The updater replaces the file in place.

Debian or Ubuntu package (.deb)

Run this command in the folder that holds the file, and type your password when asked:

sudo apt install ./Separatrix_1.0.1_linux_amd64.deb

The ./ matters. Without it, apt looks for a package called that name online instead of using your file. apt also installs the WebKitGTK libraries that Separatrix needs, if they are missing.

Fedora or openSUSE package (.rpm)

On Fedora, run this command in the folder that holds the file, and type your password when asked:

sudo dnf install ./Separatrix_1.0.1_linux_x86_64.rpm

On openSUSE, use sudo zypper install ./Separatrix_1.0.1_linux_x86_64.rpm instead.

Start Separatrix for the first time

If you installed the .deb or the .rpm, open your app menu and click Separatrix. From a terminal, run separatrix. If you use the AppImage, run the file as in the AppImage section.

Separatrix opens on a gallery of example systems from Strogatz's Nonlinear Dynamics and Chaos. Click any card to start from that system.

The Separatrix window on first launch, showing the gallery of example systems and the Open button at the top right

Open a project

Separatrix saves projects as .sepx files. You can open one in three ways:

Click Open… at the top right of the gallery, or press Ctrl+O at any time, then choose the file.
Drag a .sepx file from the Files app onto the Separatrix window.
If you installed the .deb or the .rpm, double-click a .sepx file in the Files app.

The Open File dialog over the gallery, with rabbits-vs-sheep.sepx selected

The project opens with its equations, trajectories and view as they were saved. The window title shows the file name.

Separatrix with rabbits-vs-sheep.sepx open, showing the phase plane of the rabbits versus sheep model from Strogatz section 6.4

The gallery also lists the projects you opened most recently under Recent. Click one to open it again.

Update Separatrix

Separatrix 1.0.0 cannot update itself. If you have 1.0.0, install the latest version once by following this guide from the top. From 1.0.1 on, updates install themselves.

The version you have is at the bottom right of the window.

Separatrix checks for a new version after it starts. When one exists, the status bar shows Update available beside the version. Click the version, then click Install and restart. You can click the version at any time to check by hand. If you have unsaved changes, Separatrix asks whether to save them first.

AppImage. The update replaces the file in place.
.deb or .rpm. Separatrix updates the installed package, so it asks for your password, as the first install did. You can also download the new file from the releases page, check it, and install it with the same command you used the first time.

Your projects and recent files stay where they are.

Uninstall Separatrix

Follow the line for the file you installed:

AppImage: delete the .AppImage file.
.deb: run sudo apt remove separatrix.
.rpm: run sudo dnf remove separatrix, or sudo zypper remove separatrix on openSUSE.

Uninstalling keeps your .sepx projects. To also delete the list of recent projects, delete the folder ~/.config/io.github.uncrayon.separatrix.