Octave

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GNU Octave è un’applicazione software per l’analisi numerica in gran parte compatibile con MATLAB.
Octave can be run un “traditional mode”, which gives errore when trying to use octave-only syntax.

octave --gui --traditional

Differences Octave-Matlab

• Octave supports C-style increments: i++; i+=1; ++i; ecc
• Matlab differentiates between character strings and character arrays, solution: use strcat() for character string concatenation in octave
• !string calls a shell with command “string” in Matlab, octave will not recognize ! because it is used as a logical operator. Always use system(string) in matlab.
• Matlab lets you load empty files, octave does not
• octave supports both fprintf and printf whereas matlab requires fprintf
• Matlab does not support whitespace before transpose operator A' whereas octave also support the whitespace A ', as it is considered like every other operator.
• Matlab requires ... for line continuation

rand(1, ...
2)

where octave supports this:

rand(1,
2)

 in both programs

R=[1 2 3
7 8 9]

shifts to the next row:

R=
 1 2 3
 7 8 9

• Octave supports z=y=x+3 where Matlab requires two different assignements
• Octave supports

global isOctave = (exist('OCTAVE_VERSION')>0);
 
%where matlab requires
global isOctave;
isOctave = (exist('OCTAVE_VERSION')>0);

• as for the logical NOT operator octave supports both ~ and !, where matlab only supports ~
• comments in octave can start with both # and %, matlab %
• for exponentiation octave uses both ^ and **, matlab ^
• to end block octave can use both end or specify the block with endif, endfor ecc, matlab end
• octave supports C-style hexadecimal notaion 0xAABB, matlab requires the hex2dec function: hex2dec('AABB')

Specific differences

• dbstep,in → dbstep ; dbstep → dbnext
• eig(A,B) → qz(A,B)
• time() is not available in matlab, use now()
• textscan() is not included in octave, use fscanf()
• setting labels for plots

Octave:        plot(x, y, ';label;')
MATLAB/Octave: plot(x, y); legend('label')