Lenia – Mathematical Life Forms

Lenia (from Latin lenis, “smooth”) is a cellular automaton, like Conway’s Game of Life, but with continuous states and continuous space-time. It supports a great diversity of complex autonomous patterns or “lifeforms” bearing resemblance to real-world microscopic organisms. More than 400 species in 18 families have been identified, many discovered via interactive evolutionary computation.

Paper: arxiv.org/abs/1812.05433

Code: github.com/Chakazul/Lenia

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Peter Shirley's Ray Tracing in a Weekend

I may have to abort my ray tracing app that’s been busy rendering the Stanford Dragon for over a month now. Peter Shirley’s books will teach me how to do it properly! :) In celebration of the launch of @nvidia Turing ray tracing hardware, I am making my three ray tracing books are available as free pdfs. I have donated half the money people have sent to @hackthehood, a really neat organization.
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Making a Heart with Maths

Inigo Quilez (iq) explains how to model a simple heart with mathematics. Shadertoy code and real-time version can be found here. I love how he embedded the model into the video. Need to explore how to develop plugins for AfterEffects. Jim Fowler, Professor at Ohio State University applied a similar technique in his Calculus course on Coursera. He used the old ray tracing tool POV-Ray with ArUco, a library for augmented reality applications.
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KaTeX, Khan Academy's Math Typesetting Library

Khan Academy has published the fastest typesetting library for the web. IntMath’s KaTeX and MathJax comparison demo shows some impressive performance improvements. The demo page took 177 ms to process on my laptop. The MathJax version on the other hand took 4777 ms. The performance comes at a price that not everything is supported in KaTeX (yet). I wish aligned equations were supported, but I can live with it. Until I run across more serious problems I’ll happily use KaTeX instead of MathJax.
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How to stop a hanging Windows service

Windows processes and services can be controlled with the task manager, but occasionally I found hanging processes that required a reboot. Windows has some useful command line tools that could help avoiding a reboot and save some time: 1) Open command line prompt (cmd) as Administrator 2) Find process id with sc queryex {servicename}, e.g. sc queryex Apache2.4. You can also use tasklist|find "{executable}", e.g. tasklist|find "httpd" 3) Kill the process with taskkill /f /pid {PID}, e.
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Zequals and the Art of Estimation

In this Numberphile video Rob Eastaway presents Zequals which can be useful if you need to compute a quick estimate, for example to find out if your calculation is on the right track. The idea is to ruthlessly round every number to just one significant digit. For example: 3 * 7 = 21 zz 20 7 * 8 = 56 zz 60 436 * 68 zz 400 * 70 = 28000 zz 30000 The actual answer is 29648 and surprisingly close to the zequal result of 30000.
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Breakpoint 2008

I can’t believe it’s been more than a year since I wrote about the Breakpoint. Breakpoint 2008 already took place last March on the Easter weekend, so the following is actually pretty old news. I still want to share some of my favorites though. This year’s motto of the competition was Digital Garden hinting at the annual Garden Show in Germany that took place in Bingen at the Rhine river as well.
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Breakpoint 2007

I just read an article about the Breakpoint 2007 demo-party that took place last April in Bingen on the Rhine river in Germany. Breakpoint is considered one of the biggest demoscene parties worldwide. This brought back memories of a time when I first started out with computers. Everything was so exciting. And the demoscene played a large role in the inspiration that made me pursue a career change, college and everything else that followed.
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