Lud.cc ~ Ludwig's digital home

My photos on the internet

Thu, 20 Mar 2025 00:00:00 +0000

Context

I used to take a fair amount of photos that I published on flickr. Years ago, I decided to reduce my footprint on the internet, therefore I removed them. I am glad to see some of them are used today while respecting the copyright CC BY 2.0 (2.0 was the latest at the time photos were taken).

What I found on the internet

Copenhagan, central retail district via watchpro.com
Copenhagen, Amagertorv Square via archdaily.com
Copenhagen, St. Mark’s Church via wikipedia.org
France, Ajaccio via cityzeum.com
France, Corsica via goodfreephotos.com
France, Flaine via alpinepursuitstransfers.com
France, Quartier de la Maison-Blanche via expedia.it
France, Église Notre-Dame-de-Lorette via tripomatic.com
Japan here and also here via bokete.jp
Russia, Сквер Мустая Карима, Уфа via wikipedia.org
Russia, Уфа via odia.ig.com
Many photos via commons.wikimedia.org

RSS

Tue, 11 Mar 2025 00:00:00 +0000

Main RSS Feeds

Main feed (all the publications)
Blogmarks
TILs

More RSS feeds

Each post on this website contains tags. There is an RSS feed¹ for each tag, with the following semantics:

https://lud.cc/tags/{tag}/index.xml

RSS version 2.0. ↩︎

Micromort

Tue, 18 Feb 2025 00:00:00 +0000

A micromort (from micro- and mortality) is a unit of risk defined as a one-in-a-million chance of death. Micromorts can be used to measure the riskiness of various day-to-day activities. A microprobability is a one-in-a million chance of some event; thus, a micromort is the microprobability of death.

— Wikipedia

I discovered this word while reading this question:

How many micromorts is a day in the life of a 90-year old?

Eager vs lazy evaluation

Sat, 15 Feb 2025 00:00:00 +0000

TIL `bool::then_some` in Rust

While participating in Advent of Code, I learned about bool::then_some. Because I tried to finish the problem on time, I did not read fully the documentation. I wrote a get helper function to access an element in a 2D array. The code (simplified to 1D) looked like:

fn main() {
 dbg!(get(&vec![42, 51], 4));
}

fn get(v: &[u8], i: usize) -> Option<u8> {
 (i < v.len()).then_some(v[i])
}

It compiles fine, but it crashes:

thread 'main' panicked at src/main.rs:6:29:
index out of bounds: the len is 2 but the index is 4
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

Cargo-Process exited abnormally with code 101 at Thu Feb 13 21:04:58

What is wrong with this code?

Async Pipeline Pattern - Eager to work

Tue, 28 Jan 2025 00:00:00 +0000

Async Pipeline Pattern - Eager to work. I wrote a web crawler prototype and rediscovered the async pipeline pattern. It was interesting to see how this story explored the idea more thoroughly.

A comment from Lobste.rs showed a different view on how to potentially improve it:

One thing to keep in mind is that FuturesUnordered is really just an executor like the one use to spawn tokio tasks, which can introduce its own issues when used with tokio. I would use tokio’s JoinSet in this context, rather than FuturesUnordered. In real code the image processing is presumably compute heavy and saving the image is presumably blocking file IO, so I’d actually use tokio’s spawn_blocking to move both of those steps onto a background thread for compute work.

One Billion Row Challenge

Mon, 13 Jan 2025 00:00:00 +0000

One Billion Row Challenge. The problem easily fits in your head, allowing you to think about an initial algorithm. To discover which parts of the code are slow two methods are used : flamegraph and perf. The analysis demonstrates several well-known optimization techniques, such as:

Using bytes instead of UFT8 string
Implementing faster hash functions, by dropping some characteristics (for example, resistance against HashDoS)
Utilizing Memory Map
Leveraging SIMD
Adding parallelization.

While solving performance problems often involves trial and error, it’s refreshing to read about performance optimization in a language other than C or C++.

My approach to running a link blog

Thu, 09 Jan 2025 00:00:00 +0000

My approach to running a link blog (via). The blogmarks idea is:

publishing links (which I called “blogmarks”) with a title, URL, short snippet of commentary and a “via” link where appropriate.

— Simon Willison

I discovered this concept thanks to Mario. He maintains a dedicated page for it.

This is an easy way to start writing about things I find interesting, remember them, and share them with others.

About

Fri, 22 Jul 2011 00:00:00 +0000

About me

Welcome to my digital ~ (home), I am Ludwig Pacifici.

I studied in Bordeaux and Grenoble. I work as a software engineer specialized in finance, first in Paris and now in London. I used C++ for 8 years. I have 5 years of experience with F# and C#. Now, I am working with Rust.

I am interested in programming languages and compilers. Languages I like: Rust, OCaml and Lisp dialects such as Elisp.

I enjoyed snowboarding mainly while I was a student. I did Kickboxing¹ for about 3 years. Now, I spend some of my free time cycling discovering new places near where I live.

Résumé

Fri, 22 Jul 2011 00:00:00 +0000

Summary

Educated and experienced in Information Technology and finance, I designed software for G-Research, a leading quantitative research and technology firm, and Aquis, a pan-European equities exchange. I specialize in efficient and reliable software development, Linux-based operating systems, and system programming. I am inquisitive about distributed systems, programming languages and compilers.

Lud.cc ~ Ludwig's digital home

My photos on the internet

Context

What I found on the internet

RSS

Main RSS Feeds

More RSS feeds

Micromort

Eager vs lazy evaluation

TIL `bool::then_some` in Rust

Async Pipeline Pattern - Eager to work

One Billion Row Challenge

My approach to running a link blog

Blogroll

About

About me

Archive

Résumé

Summary

Professional Experiences

OneChronos ⋅ 2025 ⋅ London, GBR

Sabbatical ⋅ 2024

Lud.cc ~ Ludwig's digital home

My photos on the internet

Context

What I found on the internet

RSS

Main RSS Feeds

More RSS feeds

Micromort

Eager vs lazy evaluation

TIL bool::then_some in Rust

Async Pipeline Pattern - Eager to work

One Billion Row Challenge

My approach to running a link blog

Blogroll

About

About me

Archive

Résumé

Summary

Professional Experiences

OneChronos ⋅ 2025 ⋅ London, GBR

Sabbatical ⋅ 2024

TIL `bool::then_some` in Rust