Hacker News: softwarehippie

Shortest-Path on the GPU: Two buckets is all you need

softwarehippie — Tue, 24 Mar 2026 16:27:59 +0000

Article URL: https://www.execfoo.de/blog/nearfar.html

Comments URL: https://news.ycombinator.com/item?id=47505190

Points: 1

# Comments: 0

Experiments.md to stay sane down the rabbit hole

softwarehippie — Tue, 10 Mar 2026 16:23:11 +0000

Article URL: https://www.execfoo.de/blog/experiments.html

Comments URL: https://news.ycombinator.com/item?id=47325365

Points: 1

# Comments: 0

New comment by softwarehippie in "Ask HN: What Are You Working On? (March 2026)"

softwarehippie — Mon, 09 Mar 2026 10:38:51 +0000

As a personal learning project on how to write efficient GPU code I'm trying to implement different shortest-path algorithms on the GPU. This is notoriously one of the cases where a simple algorithm like Dijkstra on the CPU will beat many implementations on the GPU.

It has been a lot of fun to learn about Vulkan / GLSL and the GPU execution model to figure out why the CPU is so much faster than the GPU. I'll be open sourcing the code soon but so far I'm documenting my journey in a series of blog posts. First one of the series is https://www.execfoo.de/blog/deltastep.html

Optimizing Delta-Step on the GPU

softwarehippie — Tue, 03 Mar 2026 14:15:23 +0000

Article URL: https://www.execfoo.de/blog/deltastep_shader.html

Comments URL: https://news.ycombinator.com/item?id=47232661

Points: 1

# Comments: 0

GPUs are not always faster

softwarehippie — Tue, 10 Feb 2026 16:16:19 +0000

Article URL: https://www.execfoo.de/blog/deltastep.html

Comments URL: https://news.ycombinator.com/item?id=46961971

Points: 1

# Comments: 0

New comment by softwarehippie in "Future of transportation"

softwarehippie — Sun, 20 Jan 2019 22:39:50 +0000

Pretty shallow analysis, how AVs will be deployed depends very much on the region and how it complements with existing infrastructure (especially outside the US). I can already travel at 200km/h while working in a train today - that does not make me want to move further out of a city. AVs will have a tremendous impact when it comes to last-mile connectivity or supporting a more suburban life-style, but the impact on public transportation will be limited IMHO.

I can recommend the series from a16z on the wider impact of AVs https://a16z.com/2018/02/03/autonomy-ecosystem-frank-chen-su...

New comment by softwarehippie in "Routing on OpenStreetMap.org"

softwarehippie — Tue, 17 Feb 2015 15:22:14 +0000

What you see on cycle.travel _is_ an open source router. They run https://github.com/Project-OSRM/osrm-backend Actually, I don't really see where you get that impression from. Very few commercial providers use their own routing stack. It is almost always OSRM or pgRouting if you want something that scales for world-wide routing.

New comment by softwarehippie in "Ask HN: Who is hiring? (February 2015)"

softwarehippie — Mon, 02 Feb 2015 09:55:30 +0000

Mapbox - Software Engineer - REMOTE/SF/DC - https://www.mapbox.com/blog/directions-hiring/

Got an idea for solving this problem efficiently and elegantly in C++?

    A given graph consists of two connected sub-graphs in which every node has at least three neighbours. The sub-graphs are only connected by a single edge, the bridge. Given a node in each sub-graph, find the bridge. You can assume there is only one bridge.

Send the code to jobs@mapbox.com.

Mapbox is building a kick-ass open source routing engine that works whether you’re walking, biking, or driving. We’re looking for people who enjoy polishing their C++ code to a high sheen and wringing out its last few drops of performance. Sound like you, or like where you want to get to? We encourage everyone excited about making directions better and open to drop us a line at jobs@mapbox.com.

New comment by softwarehippie in "Alligator Eggs"

softwarehippie — Sun, 18 Jan 2015 12:29:16 +0000

Yep, see http://teamcroggle.github.io/ also available in the Google Play store: https://play.google.com/store/apps/details?id=de.croggle

New comment by softwarehippie in "Ask HN: Who is hiring? (January 2015)"

softwarehippie — Thu, 01 Jan 2015 14:22:45 +0000

Mapbox, (REMOTE worldwide or LOCAL in SF/DC) https://www.mapbox.com/jobs/ Directions Developer

We’re building a routing service unlike any other. It is flexible, fast, and customizable for every use case. We are looking for people who know graph theory, efficient algorithms, and have the desire to run fast on creating a scalable API.

While having a background in routing is a bonus, we’re really looking for C++ coders with a deep understanding of algorithms and data structures. Knowledge in C++11, cache effiency as well as I/O effiency are certainly a plus.

Primary focus would be extending an open source routing engine.

New comment by softwarehippie in "Introducing Mapbox GL"

softwarehippie — Thu, 05 Jun 2014 14:56:21 +0000

You do realize that this 100% configurable by stylesheets? The entire point is, that their maps are stylable by the user (i.e. the app developer).