Monthly Archives: June 2007

Cool Feature on NY Times Website

I was just reading an article on the New York Times entitled “Science of the Soul? ‘I Think, Therefore I Am’ Is Losing Force” and while reading I came across the word “palaver” in the text. Not knowing its meaning I double clicked on it to highlight it so I could easily paste it into Ubuntu’s dictionary, but there was no need. The website popped open a window with the definition for me. Pretty cool! I wonder how long this has been working?


Sierpinski Tetrahedron (Tetrix) C++ Code

I modified my Sierpinski triangle code from a previous posting to work in three dimensions instead of two. The result is a short C++ program which will generate all the points of the Sierpinski tetrahedron and write them to stdout (you can redirect to a file).

Below is the obligatory image. This doesn’t look great but if you plot it yourself in gnuplot or some other package, you can probably get a prettier looking picture.

Sierpinski Tetrahedron


Cool Ubuntu Desktop Trick

I just discovered that you can switch among open applications by positioning your mouse cursor over any app icon in the bottom toolbar and then scrolling your mouse wheel. Before I would always use Alt-Tab from the keyboard. Now I can use the mouse method when my hands are not on the keyboard.


Sierpinski Triangle C++ Code

If you like pretty pictures, and I know you do, below is a plot of Sierpinski’s Triangle which you can generate with the short C++ program I wrote. This is an example of a fractal–an object that is self similar at all levels of magnification.

Sierpinski Triangle

On a Linux/UNIX system, to compile and run the code type:

$ g++ -o sierpinski
$ ./sierpinski >out
Enter depth (integer > 0, usually 10 is good): 10
Enter contraction mapping constant (for example 0.5):  0.5

Now the points are stored in a file called ‘out’. To plot them you can use gnuplot like so:

$ gnuplot
gnuplot> plot 'out' with points pointtype 0

Orest Symko’s Research on

I have an RSS feed from Boing Boing on my Google home page, and today they have a posting about University of Utah physics professor Orest Symko! The post describes his research into turning waste heat into electricity via an intermediary acoustic step.

It seems to me that the solar updraft tower might be a good match for this technology.


Kaliope Now Includes Gravitational Potentials

I’ve added a C++ class that handles gravitational potentials to my Kaliope project. Below is a picture of a binary cluster orbiting around a logarithmic potential well. A logarithmic potential is the simplest kind of potential well. It corresponds to an inverse distance radial force field.


Here is a slightly different simulation, with each body given its own color, so it is easier to see individual paths: