I have been learning the coursera Machine Learning Course by Andrew Ng for two weeks now. Machine Learning is fun and different. For the coursera assignment1 of linear regression, I want to share something.
Using matlab
I think matlab is better than octave, please use coursera account. Install matlab
Octave Install
The course use Octave/Matlab for programming practice. I learned octave basics in two days. I don’t have too much time, can just doing these homework in weekends. For Octavel installed on mac, I encounter some problems and solved it. Now octave is 4.2.0, I think ocatve is better now.


if you encounter some problem, you can solve it as follows:
 brew update && brew upgrade
 brew tap –repair
 brew install octave
 install xserver(seems no need to install)
 font can’t find when plot
 export FONTCONFIG_PATH=/opt/X11/lib/X11/fontconfig
 can’t plot unknown or ambiguous terminal type; type just ‘set terminal’ for a list
 brew uninstall gnuplot
 download and install aquaterm: https://sourceforge.net/projects/aquaterm/?source=typ_redirect
 brew install gnuplot –withaquaterm –withqt4
 add start config to /usr/local/share/octave/site/m/startup/octaverc
 PS1(‘>> ‘)
Gradient Descent Algorithm
Implementing gradient desenct algorithm in vectorization style was more efficient than iteration algorithm. Here is my implementation:
No for loop looks elegant.


Another implementation by my wwzyhao
[by wwzyhao]


Not better than me! haha~
My assignments on github
Assignments1
For submition errors, please refer toJacob Middag