openfluids is a home for small, focused, open packages built around dynamical systems, chaos, and the spectral analysis of spatiotemporal data. Each tool does one thing, and is meant to be read, reused, and combined.

fftkit — spectra of physical signals, and one FFT API over eight backends (SciPy, NumPy, Intel MKL, CuPy, PyTorch, TensorFlow, pyFFTW, Accelerate). spectrum() handles the resampling, detrending and windowing a non-uniformly sampled record needs, and reports what it did; below that, swapping backend= leaves your call sites alone.

openmodalpy — nine modal decomposition methods for spatiotemporal data behind one API: POD, mPOD, PSD-POD, SPOD, ST-POD, DMD/HODMD and BSMD, driven by a config file or a CLI. Pure NumPy/SciPy, no external solvers.

dynachaos — dynamical-systems analysis of measured or simulated time signals: maps and coupled-map lattices, Lyapunov exponents, recurrence quantification, entropy diagnostics, correlation dimension and multifractal spectra, with Rust-accelerated kernels where those have parity tests.

dsgbr — spectral peak detection for noisy power spectra that slope over several decades, using a Savitzky–Golay search scored against a rolling-median baseline rather than a fixed threshold.

chaos-atlas — an interactive explorer for chaotic dynamical systems: strange attractors, bifurcations, Lyapunov exponents, fractals and coupled-map-lattice patterns. Runs in the browser; the map kernels also ship as a Python package.

quadros — turns simulation snapshots into checked frame sets and videos. Runs locally, over SSH, inside a container or from a scheduler job without copying scripts into case directories, and writes a manifest of what it rendered so dense snapshots can be deleted with something to check against. Nek5000 has dedicated support; other formats go through PyVista.

hpckit — drives Slurm work from a local checkout: remote tool checkouts, an immutable virtualenv per commit, run packets, submission and polling, receipts and artifact sync. The tools it runs are declared in your own config file — it ships none of them, and needs nothing but a YAML parser itself.

They are built to compose: openmodalpy runs its transforms through fftkit, so a backend installed once is available to everything above it. hpckit and quadros pair the same way — hpckit submits the run, quadros renders what comes back — but they stay separate installs on purpose, since a machine that only submits jobs should not pay for VTK.

More tools will appear here as they are released.