Very short Matlab/Octave tutorial


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Start Octave/Cygwin

  • Click on Cygwin icon
  • type "startx" in newly opened window with the black and green icon
  • may open new terminal by type "xterm &" in window with the X icon on the left
  • type "octave" in one of the windows with the X icon on the left. This is your octave session. All octave commands have to typed there

Basic commands of octave

Normally Matlab/Octave shows the results of each operation on the screen. But if the data set is large, you can suppress the output by adding a semicolon (;) at the end of the line.


list content of directory


changes directory to DIRECTORY_NAME


Loads programs defined in DIRECTORY_NAME


loads an Ascii file


loads a binary file named FILE_NAME and places it in variable A


loads a binary file named FILE_NAME and places it in variable A

whos A

shows information of the matrix A, in particular its size

B = A';

transposes matrix A in placed it in B

B = reshape(A,[n m p]);

changes the dimension of matrix A in [n m p]

pcolor(A), shading flat, colorbar

draws matrix A. The colors represent the values of the elements of A and the axis are the dimensions of the matrix

find(A == 11);

finds the indexes of all elements of A equals to 11

A(find(A == 11)) = NaN;

replace all elements in A equal to 11 to NaN

B = squeeze(A);

remove the dimensions of size 1 of the matrix A and place the result in B

% some explanation

lines starting with % are ignored. They are used to comment the program.

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