Unpack Basilisk and enter the source directory:

wget -q http://basilisk.fr/basilisk/basilisk.tar.gz
tar zxf basilisk.tar.gz
cd basilisk/src

On Linux use:

cp config.gcc config

On macOS use:

cp config.osx config

Build and install qcc

make ast && make qcc
mkdir -p "$HOME/.local/bin"
cp qcc "$HOME/.local/bin/"

Build a.aut:

qcc -disable-dimensions main.c -O2 -lm

Run with parameters xc0 yc0 omg0 xc1 yc1 omg1; domain is [0,1] x [0,1], and vortex strengths omg0, omg1 can be negative.

./a.out 0.5 0.5 1.0 0.6 0.8 1.0

main.c writes per-snapshot raw fields to a.*.attr.raw; omega is the first field in each record. post.py reads these files, writes per-snapshot images a.*.png, and creates omegas.npy with shape (nsnap, n, n).

Generate PNG frames:

python post.py

Create an animation with ImageMagic, comand can be convert in older versions:

magick a.*.png img/a.gif