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)

Note: I’ve later found that if you have XFCE installed, even if you’re using the standard Ubuntu Unity desktop, the process below doesn’t help. ———————– Ubuntu uses Gnome Agent, which 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 […]

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 […]