(Lists of (Lists of (Lists of …)))

The title of this post is inspired by the syntax of Lisp. This is my small tribute to that great programming language. Because lists are - as we all know - one of the most advanced data structures out there.

Add a little bit of prefix notation to the mix and quickly you realize: OOP considered harmful.

But let me start from the beginning.

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Say Say Say!

Once again a post in the category “Misc - and yet mainly computer science”.

You can never put enough projects on ice out of the blue and start new ones at the same time. So it happened a few days ago that I asked good old Roger what one could build. “Make a Chip-8 emulator!”

At first I was a bit sceptical about the idea - too simply 😉 too little, already exists. Out of sheer boredom, which already threatened to tip over into desperation, I had started with it. With Python. And with Pygame.

The actual code is ugly, badly commented (17 mini-comments for ~300 lines of code), badly hacked together, incomplete and very slow at large pixel sizes.

So the best premises to release this thing into the world.

Programs can be found on the net (e.g. here). If something doesn’t work, then it’s probably because not all op codes are implemented yet. The emulator then aborts and writes the missing code to stdout. So if you want to do fix things up, look it up on Wikipedia and/or here.

Processing with Processing

A long time ago I had already found the project Processing, but then somehow forgot about it again.

Two days ago I was looking at this Java-Animation-Framework again, this time with the funny “World of Sand” Java Applet or more precisely with the derivative Hell of Sand.

According to Wikipedia, Processing is suitable for beginning programmers and designers, to develop visual animations and for prototyping.

The advanced hobby developer immediately notices that it is nothing more than Java. To get a complete Java program, you only have to pack a few imports and so on around the so-called PDE code.

I sat down earlier to build something simple. My little work can be seen here as a Java applet. (Note: Just click in it with the mouse.)

Great thing of this Processing - and OpenSource (LGPL) at that.

Cool animations and entertaining gadgets can be found on the net. Just Google for them.

MMIX drives Apache

In the course of the Info II lecture I did an experiment to get MMIX to work via CGI with Apache.

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Fun with waves

Now that I have more or less successfully completed my chemistry exam, I can devote myself to my private research again. The fact that I am not yet completely free from physical chemistry (which is quite interesting after all) can be seen in my last experiment.

I wanted to work with the representation of periodic functions. The picture is painted pixel by pixel by a small Java code. The concentric circles are superimposed sine functions with different frequencies and each shifted on the X-axis. What caused me most problems, however, was that the arc only maps sine to [-pi/2;+pi/2]. How could I have known ^^. This is why the colors took me a little longer :-).

Anyway… I guess I’ll turn back to fluids now - this time based on Mark Carlson’s dissertation “Rigid, Melting, and Flowing Fluid”. In contrast to the standard paper “Realistic Animation of Liquids” by Foster et al, the numerical boundary and stability conditions are described in detail here. Last time I had to guess that part.

Realtek 8180 for fli4l

After one week of testing I finally finished OPT_R8180, an optional fli4l package. Me not having done much but compiling the driver and writing some minimal scripts needed by fli4l, all the credits go to Andrea Merello for providing the source code.

get the package here

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Contact

Alexander Gitter
contact at agitter net