Octave vs. Matlab

• Since most of the commands are the same for Matlab and Octave, we will use Matlab to mean either of them.
  • Parts that are valid only for Matlab will be colored like this;
  • Those valid only for Octave will be colored like this (at least for now).
• Documentation, tutorials etc. for Matlab are on its page. See also the Help item on the left.
• At last checking, the FAQ for octave is at http://wiki.octave.org/FAQ.
  A good place to start is http://wiki.octave.org/GNU_Octave_Wiki, this summarizes the main links of http://wiki.octave.org/, including installation.
• For code to be portable from Octave to Matlab, the most notable differences are:
  • Strings in Octave are enclosed between either double or single quotes; Matlab accepts only single quotes.
  • The comment character for Matlab is %, whereas Octave accepts both % and #.
  • function can end in Octave with either endfunction or end; Matlab accepts only end.
    The same applies for a few other end-tags.

Octave/Matlab vs. Mathematica

• In Matlab all data is stored as a matrix (as opposed to the lists used by Mathematica).
• The first practical difference is in plotting: for Mathematica it was enough to give a range, as in

  Plot[Sin[x], {x, 0, 2*Pi}]

  but for Matlab one has to give the explicit values where to compute the function, as in

  t=linspace(0, 2*pi);
plot(t, sin(t))

  • Here linspace(a,b) creates a list (excuse me, array) of values equally spaced between a and b; the default is to create 100 values.
  • The semicolon at the end of linspace(0, 2*pi) suppresses the output. Try linspace(0,1,5) to see the values generated.
  • Now try linspace(0,1,25). Since the output does not fit on one line, it is displayed with column numbers:

      
    linspace(0,1,15)
    ans =
    
     Columns 1 through 10:
    
       0.00000   0.07143   0.14286   0.21429   0.28571   0.35714   0.42857   0.50000   0.57143   0.64286
    
     Columns 11 through 15:
    
       0.71429   0.78571   0.85714   0.92857   1.00000
    
      

• Unfortunately .m is the extension for certain Mathematica files too.
  Moreover, the extension .m corresponds to the MIME type application/vnd.wolfram.mathematica.package
  It is possible that on a machine that has Mathematica installed such files are considered Mathematica files, even if they contain Matlab/Octave code.
  What can be done is to add another option for opening these files: Notepad or preferrably Notepad++ (whose executable, notepad++.exe, is in the Octave folder, in the subfolder tools).