slippens's blog

When you point your Mozilla or Firefox browser to a malformed url, for example http//www.google.com (no : after the http) or http://http://www.google.com (two times http://), you don't end up where you would expect. English google users would get served with Micrfooosobarfts website, while I (a Belgian/Dutch google user) end up at Elsefoovier.nl. This page explains what is happening here. And to follow the proposed solution, I'll put here a link to information about http.

This weekend I encountered a weird problem during programming C extension modules for Python. For some obscure reason floats from my C extension modules were formatted with a comma as separater (e.g. 123,456) instead of with the more familiar point (e.g. 123.456). Obviously some locale related problem. Most of my desktop and applications are set up for Dutch (my native language), but when I'm programming/working I use English and scientific conventions (e.g. a point as decimal separator). After isolating the problem I found out it was related to importing the pylab (aka Matplotlib) module (which I started using for plotting graphs and figures from Python). The following situation illustrates the problem.

A weird outcome of a halftoning experiment. Not what I would call a good halftone, but it's nice on itself.

Scipy is a (set of) open source Python modules for scientific/mathematical/engineering stuff. I (try to) use it instead of Matlab or its open source clone Octave because I don't like Matlab's scripting language and prefer Python's programming features.

If you want to store a 2D array (aka matrix) to an image file, the default behaviour of Scipy's imsave() function is to rescale the matrix to a 0-255 range (like Matlab's imagesc() function). For example:

The OpenDocument file format (aka "OASIS Open Document Format for Office Applications"), is an open and free standard for office files. It's fairly easy to read OpenDocument files in/from Python. Basicly, an OpenDocument file is just a zip archive but with another extension (".ods" spreadsheets, ".odt" for text documents, ".odg" for graphics and so on). The files in the zip file are mainly some XML files, like content.xml, settings.xml and styles.xml.

Basicly, we just need two standard python modules from the nice standard Python library to extract data from a OpenDocument File: zipfile for handling the zip compression and xml.parsers.expat (or another xml parser module) for parsing the xml. A possible/simple/minimal way to do read a fictional spreadsheet file pelican.ods is as follows:

I want to share an image with the world.
It is not art. It is just the result of a experiment that — how should I put it — went wrong.

To be continued

Man, this is heavy linux/unix commandline fun:

which which
locate locate
man man
help help
info info
whatis whatis
echo echo
touch touch
yes yes
whereis whereis

It's a simple concept, but I already lost a lot of time looking for the solution: changing the active (aka default or just render) camera in Blender. I just can't find any clue in the (context) menus or in the wikified Blender manual. Google directed me to this Blender survival guide in which the solution is concealed:
select the camera which you want to make active and press ctrl + numpad-0

Today I bothered to intall the Last.fm player just to give it a try. The installation (on my Kubuntu 5.10 Linux laptop) was very easy. I just downloaded a tarball with the Linux binary from the Last.fm player download page and extracted it to a local folder in my home directory. Next I had to tell my webbrowser (firefox) to use this player for links with the lastfm:// protocol (like explained here). That was all to make it work.

If you you want to use normal text in a math environment (mathdisplay, equation,...) you should use \textnormal{} instead of \textrm{}. Apparently the latter is more popular: a google search for "latex textrm" delivers almost 25.000 hits, whereas google search for "latex textnormal" returns not more than 800 hits. The advantage of \textnormal is that the text will be typeset in the normal font of the body text. \textrm on the other hand activates a roman (serif) font. Most of the time the result of these two will be the same because the default font of the body text is a serif one in most cases. But sometimes it is not.