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My random knot in the Web

Welcome

This is my home in the virtual world, where I write about things that I want to share. The freely available software that I've written as well as some of the photographs I've taken over the years can also be found here. Please use the navigation links on the right if you are looking for something.

Recent articles

  1. Building vkQuake 1.20.3 on FreeBSD

    The FreeBSD port is relatively old, and doesn’t support SDL 2.2. So I built version 1.20.3, which is current at the time of writing.

    The requirements are the same als the port.

  2. On Python speed

    As an engineer, I write a lot of small python programs as tools for specific tasks. Generally, these are not large programs. Most of them are below 100 lines of code (“LOC”, as measured by cloc), although there are a few in the 300−400 LOC range.

    In this article, I will present some observations about these, and draw some conclusion from them.

  3. Python 3.11 speed comparison with 3.9

    Since Python 3.11.0 came out recently, I wanted to compare its speed with 3.9.15 on some of my own “benchmark” programs.

    Both versions are in the default configuration as built by the FreeBSD ports system.

    TL;DR Python 3.11 yielded speed improvements in the order of 25% in my tests.

  4. FreeBSD 13.1 install on a Lenovo IdeaPad 5

    When I originally got this machine, I needed it for $WORK. That is no longer the case, so I wanted to install FreeBSD 13.1 in combination with ZFS to gain experience with the latter.

    TL;DR Nice and quiet. Slightly faster than my i7-7700 workstation. Except for wifi, everything works.

  5. Resonance frequency of a composite tube

    Based on a question I ran into at work, I wanted to explore the influence of parameters like cross-section, wall thickness and laminate lay-up on the resonance frequency of a carbon fiber composite tube.

    The goal of this exercise is to determine which of the parameters are dominant.

  6. Using sed

    As I’ve written about before (see engineering), I often use CalculiX for structural mechanics calculations of products made from composites. These often involve calculating lots of different combinations of materials, lay-ups and load cases. For convenience and for them being self-contained, each variant is usually in a different directory.

    So when I find an improvement to e.g. a pre.fbd, Makefile or job.inp, I want modify all of the other instances as well. This is where sed (which stands for “stream editor”) comes into play.

    date: 2022-05-22
    modified: 2022-08-31
    reading time: 5 min.
    category: howto
    tags: sed

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