Hi, I’m Jens Stücker

I’m a cosmologist studying dark matter and the dynamics of cosmic structure. I develop simulations and computational tools to understand how these structures form and evolve.

Here I share my research, open-source codes, and notes on scientific computing.

Research, code & notes

JZ-FMM

GPU-native differentiable N-body simulations with the Fast Multipole Method

Oct 15, 2026 Codes

Plane-based tree hierarchy and its contiguous data layout

JZ-TREE

Neighbour search, friends of firends and other dual tree walks on GPU

Oct 15, 2026 Codes

Jax's auto-diff

How derivatives are traced in JAX

Dec 8, 2025 Tutorials, Jax

Optimizing jax.jit

Low-level insights on how to optimally fuse kernels with `jax.jit`

Oct 12, 2025 Tutorials, Jax

Best Practices: Cheat Sheet

A small overview over useful python commands and good practices

Oct 8, 2025 Tutorials, Python

Tutorial II: Testing Code

How to test numerical code systematically with unit tests.

Oct 8, 2025 Tutorials, Python

Tutorial I: Creating a Python Repository

How to create a well structured python code repository, that could later be published as a package.

Oct 5, 2025 Tutorials, Python

Tidal Stripping

An Overview on my research on tidal stripping

Oct 4, 2025 Research

Warm Dark Matter

An Overview on my research on Non-Cold Dark Matter