eigshow function

[Vito De Tullio]

Hi all.
I'm a newbie octave user. For my exam, I need to use matlab, but I found
octave (for linux).
It works for all, but I need to use a function, eigshow, that's not present
(is present in matlab). It should draw a graphic with 2 lines representing
eigenvalues and eigenvectors...

Surfing on the net, I found some implementations, but all of them gave me
errors in octave.

http://web.mit.edu/18.06/www/Course-Info/Mfiles/eigshow.m
http://kom.aau.dk/~borre/kalman/lecture3/eigshow.m
http://www.cs.ubc.ca/~mpf/cpsc402/downloads/eigshow.m

for example the first give me

octave:1> eigshow
warning: get: invalid property `tag'
error: `x' undefined near line 29 column 30
error: evaluating argument list element number 2
error: evaluating assignment expression near line 29, column 12
error: evaluating if command near line 28, column 3
error: called from `isequal' in file
`/usr/share/octave/2.9.12/m/general/isequal.m'
error: if: error evaluating conditional expression
error: evaluating if command near line 51, column 1
error: called from `eigshow:initialize' in file `/home/zed/eigshow.m'
error: evaluating if command near line 33, column 1
error: called from `eigshow' in file `/home/zed/eigshow.m'
octave:1>

can you help me?

-- 
By ZeD