Gnuplot Refences

• Kawano – not so Frequently Asked Questions
• Gnuplotting — Create scientific plots using gnuplot
• Impossible Gnuplot Graphs – made possible
• Gnuplot tricks: Broken axis revisited – breaking axis
• WikiBooks: Gnuplot – still sparse

To be updated …

LaTeX References

• WikiBooks: LaTeX
• TeXample – lots of samples
• Poor man’s collaborative editing:
  • docs.texlab.org – Google Docs with preview
  • ScribTex – Online filesystem editor with build option
• Sketch – 3D illustrations
• Inclusion of Blender models – via Sketch (see above)
• Beamer Theme Matrix – themes for presentations

To be updated …

Python References

• Dive Into Python
• Porting C extensions from Python 2 to Python 3 (haven’t tried it yet)
• Python Introduktion (danish only)
• Understanding Threading in Python – a Linux Gazelle article
• Multiprocessing package – a better threading module?
• Python’s Super is nifty, but you can’t use it – basically a ‘Considered Harmful’ article
• pySerial – portable module for accessing the serial port
• Print without a new line or space in Python – a real print function for python

To be updated …

Choosing the right architecture for DEB packages

I recently experienced a minor run-in with dpkg-deb. My system tells me, that

$ uname -a
Linux hoazin 2.6.28-16-generic #55-Ubuntu SMP Tue Oct 20 19:48:24 UTC 2009 i686 GNU/Linux

which seems to indicate that the Architecture field of the DEBIAN/control file should read ‘i686‘. Doing this results in the error:

deb Error: Wrong architecture 'i686'

Dismembering official packages reveals ‘i386‘ as the correct value.

Rossum Corporation

The way Rossum Corporation describes themselves is quite scary. Could their internship qualifications sound any shadier?

“New for 2008, the Rossum Corporation offers exclusive 5-year paid internships for candidates of superior genetic disposition. Contact a Rossum Human Recruitment office near you for more details.”

Timetraveling with GIT

or checking out a specific commit.

First, one has to locate the hash of the commit. This can be done by:

1. Scanning the log by running “git log” (press q to quit). Look for lines labeled commit.
2. Scanning the log in giggle. Look for the SHA-line. Example:
   

In this case our hash is 7f8d2051582dd030e3c07ded70010af033461e31.

Then, come up with a name for a branch to refer the this specific revision. For this example we will use old-branch.

Last, set up the branch by running:

git checkout -b old-branch 7f8d2051582dd030e3c07ded70010af033461e31

Syntax: The general syntax is: “git checkout -b BRANCHNAME HASH”

Making BOINC work under Karmic

Since installing Karmic on my laptop, it has consistently failed to connect to the World Community Grid server.

Symptoms: When going the the ‘Messages’ tab of the ‘Advanced View’, one is greeted by lines of the form:

2009-11-05T12:56:47 CET|World Community Grid|Sending scheduler request: Project initialization. Requesting 1 seconds of work, reporting 0 completed tasks
2009-11-05T12:56:50 CET||Project communication failed: attempting access to reference site
2009-11-05T12:56:52 CET|World Community Grid|Scheduler request failed: Peer certificate cannot be authenticated with known CA certificates
2009-11-05T12:56:53 CET||Internet access OK - project servers may be temporarily down.

Solution: After some googling I came across this page, which basically gives a simple workaround:

sudo su
cd /var/lib/boinc-client
mv ca-bundle.crt ca-bundle.crt.backup
wget http://boinc.berkeley.edu/trac/export/16195/trunk/boinc/curl/ca-bundle.crt

I’m not convinced that it will survive an update though.

Measuring the Desktop

From time to time one needs to measure stuff on the desktop. You might – for instance – want to know whether some region of an image will fit nicely into some part of a webpage.

In ubuntu (both jaunty and karmic releases) the screenruler application provides an easily available mean to do just that. This application is available through a package of the same name and can be found in the menu under Applications -> Accessories -> Screen Ruler.

The screenshot above shows two instances of screenruler along with the contextual menu (available through right-click or a menu button which appears when the mouse hovers over the ruler). Through this menu the metric can be changed. The length of the ruler can be changed by pulling in the ends and the orientation can be flipped by middle-clicking.