EuroPython and EuroSciPy 2025

ARC Collaborations Hour

Patrick J. Roddy

2025-11-18

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EuroPython

14th-20th July 2025

Weekend Before 😴

UCL Team 2 at UK Challenge 2025.

Flight

The Conference

24th EuroPython
7 days (2 tutorial, 3 talk, 2 sprint)
1300+ attendees
180+ speakers
Retro gaming station
Two socials
Beginners day
Summits: (WASM, C-API, Rust, Packaging)

A selection of retro game consoles. — Retro Games

The view from the conference centre. — Conference View

Tutorials

GIL-free Python and the GPU: hands-on experience
The Mighty Dot - Customize Attribute Access with Descriptors
Accelerating Scientific Python: JAX, Numba, and Ray in Action

Talks – Highlights

Myths and fairy tales around Python performance
Typing at scale: statically type-checking a large codebase
Why it took 4 years to get a lock files specification
Snapshot Testing: A New Era of Reliability
End to End with Testcontainers and Playwright

Talks – Highlights

What comes after Rust in the Python ecosystem?
What does = do?
Python Config That Will Give You Chills (In a Good Way, I Promise!)
“Python: the Documentary” screening and Q&A

Sprints

In conjunction with a beginners day.
Wanted to contribute to a bigger project.
Worked on Apache Arrow on adding typing to the Python bindings.
Tried out astral-sh/ty.
Early prototype.

Running

A map of my runs in Prague.

Tried and failed to script this up 😞…

Photos

The walk to the conference centre.

The Prague train restaurant.

Kafka's rotating head.

The Vltava River at night.

The astronomical clock.

The metronome in Letná Park.

A fun tunnel.

Unlimited dumplings.

The view from Divoká Šárka.

Tabor Gate.

Summary - Prague

Been once before to watch Cyclo-cross World Championships.
Beautiful, especially all the pastel houses.
Pretty good for running.
Meant to be warm in summer 🥶.
Plenty to do if not at a conference.
Nice to wonder around at night.
Good food scene (especially dumplings/beer).

Summary - EuroPython

Massive conference.
Many recurring attendees.
Many big cohorts in attendance - could be hard to meet people.
The community felt somewhat insular.
Talks in general of high quality.
Had to arrive early to attend some talks.
Sprints well attended.

EuroSciPy

18th-22nd August 2025

Flight

Photos – Warsaw

Many tanks for Armed Forces Day.

The one street in Warsaw that was not bombed.

A model of a synagogue in the POLIN museum.

A yummy pizza.

A fountain that moves to music.

A cool mouse.

The Palace of Culture and Science.

A cool bridge.

Train

The Conference

17th EuroSciPy
5 days (2 tutorial, 2 talk, 1 sprint)
100+ attendees
20+ speakers
One social

Tutorials

Guardians of Science: A Python Tutorial on a RAG-Powered Compliance Plug-In and Ethical AI tools
Skrub: machine learning for dataframes
Use napari for easier interactive extraction of knowledge from images and other spatial data
Compress, Compute, and Conquer: Python-Blosc2 for Efficient Data Analysis

Tutorials

Talks – Highlights

A Hitchhiker’s Guide to the Array API Standard Ecosystem
Array API and library dispatching discussion
EffVer: Versioning code by the effort required to upgrade
Standardised Quantity/Unit APIs discussion

Poster

My poster on the Array API in GLASS.

Submitted based on current project.
Coincidence that Array API was a conference theme.
First time using Inkscape.
Stored on website as an SVG https://paddyroddy.github.io/posters/euroscipy-2025/index.svg.
Lots of discussion.

Sprints

array-api-extra: Extra array functions built on top of the array API standard.
Implemented the nan_to_num function (data-apis/array-api-extra#398).

>>> import array_api_extra as xpx
>>> import array_api_strict as xp
>>> x = xp.asarray([xp.inf, -xp.inf, xp.nan, -128, 128])
>>> xpx.nan_to_num(x)
array([ 1.79769313e+308, -1.79769313e+308,  0.00000000e+000,
       -1.28000000e+002,  1.28000000e+002])
>>> y = xp.asarray([complex(xp.inf, xp.nan), xp.nan, complex(xp.nan, xp.inf)])
>>> xpx.nan_to_num(y)
array([ 1.79769313e+308 + 0.00000000e+000j, 0.00000000e+000 + 0.00000000e+000j,
        0.00000000e+000 + 1.79769313e+308j])