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knutae

55 karma · joined November 20, 2010

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knutae··on Simula – The forgotten programming language
And the old(er) building right next to it is named after Kristen Nygaard.

Simula was used as the first programming language for informatics students at the University of Bergen until the mid 1990s, when they switched to Java. I was among the last batch of Simula students there.

knutae··on L-systems
Aristid Lindenmayer used it originally as a model to study the growth of algae, so it has some scientific applications. While computer graphics is the most common use case, L-systems have also been used for generating music.

http://algorithmicbotany.org/papers/ has a list of papers and other related texts, including the classic book The Algorithmic Beauty of Plants.

knutae··on L-systems
I wrote an L-systems implementation in Common Lisp as part of a thesis around 2002. The software, thesis and some raytraced images are still available at my old university home page: http://www.ii.uib.no/~knute/lsystems/llisp.html

If anyone plans to test the software: I haven't run it in ages, and I suspect that the OpenGL bindings will be tricky to get working today. The rest of the code hopefully still works.

knutae··on Fish: A user-friendly command line shell for macOS, Linux, etc
Agree with these, and would like to add one more:

  $(subcommand)
as an alternative to

  (subcommand)
PS: I have been using fish as my primary shell for about a year now, very happy with it. :)
knutae··on Weird Python Integers
For comparison, integers in clisp:

  [1]> (eq (expt 2 47) (expt 2 47))
  T
  [2]> (eq (expt 2 48) (expt 2 48))
  NIL
Explanation here: https://www.cs.cmu.edu/Groups/AI/html/cltl/clm/node17.html
knutae··on Humpback whales around the globe are mysteriously rescuing animals from orcas
Humpback whales apparently have to defend their juveniles against hunting orcas. It is surprising that they would defend other species in the same way, but it seems likely to be the same instinct that causes them to protect their own, rather than altruism.

Then again, maybe you could make the same claim about humans. :-)

knutae··on Scroll Slow. Have Fun
Interesting, indeed. I didn't get that, but it is probably similar to the effect caused by videos like this: https://www.youtube.com/watch?v=tVgOLWVYytM
knutae··on WebGL Terrain Flyover Demo
After using Delphi professionally for some years, I pretty much hated it. Some of my least favorite features are automatic and locale-dependent string/WideString conversions, and that there are multiple memory models: interfaces (IUnknown) uses reference counting, TComponent is owner-based, and lots of other classes require manual memory management.

On the other hand, the object system has some nice features. I miss AfterConstruction and BeforeDestruction in other languages, and I like virtual constructors.

knutae··on Steam loses user database
Running a hash function directly on a hash makes little sense. You probably meant:

    md5(md5(password) + user_salt)
knutae··on Toward Better Master Passwords
I don't know... why should I worry about Dropbox security in this context? The risk that someone could steal my Dropbox data is of course there, but that they then would be able to decrypt the password database (or bother to spend resources on trying) seems very unlikely.

The only thing I'm a bit worried about is accidentally deleting or corrupting the password file, as Dropbox could then synchronize this change across all devices. I guess I should back it up regularly to non-Dropbox folders to avoid losing all my passwords.

knutae··on Toward Better Master Passwords
I use KeePass and synchronize the database file through Dropbox. I can recommend this combination, it works well both on my computers and (Android) phone.

The downside is that I sometimes have to enter the master password on my phone's on-screen keyboard, so it is probably shorter than it should be.

knutae··on Color wheels are wrong? How color vision actually works
I find the CIE Standard Observer graph enlightening: http://en.wikipedia.org/wiki/CIE_1931_color_space#Color_matc...

As far as I understand this, the red function, which corresponds to the red receptors in a typical human eye, reacts mostly to high wavelengths, but also has a small spike in the lower end of the spectrum. This explains why the violet end of the spectrum looks similar to red to human eyes, and this is probably why color wheels seem so natural. After all, a color wheel is almost the same as rainbow that wraps around.

I also find it fascinating that the CIE color space was defined as early as 1931.