Monthly Archives: September 2013

Matlab: Creating multiple data cursors

You can create multiple data cursors in a plot, handy for pointing out multiple data values, by first placing your first data cursor, then right clicking and selecting “Create New Datatip” Then you can: * move the datatip by left-clicking and holding while moving mouse around–you can put the datatip to NW,NE,SW,SE of data point […]

Quote of the Day

Some think the Earth is spherical, others that it is flat and drum-shaped. For evidence they bring the fact that, as the sun rises and sets, the part concealed by the Earth shows a straight and not a curved edge, whereas if the Earth were spherical the line of section would have to be circular […]

Comparison of Clang 3.2/3.0 and g++ 4.7.3/4.6.3

Comparison is extremely informal, using non-vectorized code that does a lot of multiply/divide/exponent/add. Just trying to get a handle on option performance–Phoronix this isn’t! End result: using -march=corei7-avx -mllvm -vectorize-loops on clang++ 3.2 Ubuntu 13.04 was the fastest by about 25% advantage over g++ 4.6/clang++ 3.0versions on Ubuntu 12.04, same CPU type Both PCs used […]

Octave “doc” not working

If you get an error message about missing files when using the “doc” command in octave, you probably need to try: sudo apt-get install octave-info

Raspberry Pi: Practical Uses Review

The Raspberry Pi ARM computers have excited a lot of people — I was in the first groups to have them, having Model B of the 256MB and 512MB varieties. Here are some things I’ve tried using the Raspberry Pi Model B 256/512MB for, with the following number ranking (my opinion only, others may fervently […]

Octave: getting xlsread() to work fully (via installing java package)

Certain functionality of GNU Octave (partic sudo apt-get install openjdk-7-jdk sudo octave setenv(“JAVA_HOME”,”/usr/lib/jvm/java-7-openjdk-amd64″) pkg -verbose install -forge java (wait about 2 minutes) exit octave pkg load java pkg load io if you get errors about missing jni.h, be sure the JAVA_HOME is specified correctly above. Note: Some users still have trouble getting xlsread to work […]

Ubuntu: disable Gnome Keyring SSH Agent (make Ubuntu NOT remember SSH private key passwords)

Ubuntu (at least 12.04 – 13.04) has the undesirable default behavior of remembering SSH private key passwords until you log out. I don’t like the remembered private key passwords, since if someone knows my Ubuntu user password, they would then have access to any SSH private keys I loaded during that session (since last logon). […]

Overview of free 2D CAD options for Linux – 3Q2013

As of 3Q2013, there are a few leading choices for 2D CAD software for Linux. In short, if you have a specific need to work natively with DWG (e.g. customer demands DWG, and DXF is not acceptable to them (sigh)), then you can try the free-of-charge but non-libre Draftsight. If you like libre software, you […]