What does each line of this Matlab code mean?

Dear all:

Any one could help me with this problem:

What does each line of this Matlab code mean?

Thanks a lot!

Ruming

[Walter Roberson]

http://www.mathworks.com/matlabcentral/answers/298051-hi-all-i-am-an-amateur-in-matlab-please-could-anyone-help-me-with-the-detailed-line-by-line-code-fo#comment_382863