Information Technology Services Centre The Chinese University of Hong Kong WKS404 MATLAB for UNIX QUICK START GUIDE Version 1.3 November 2007

1. Introduction

MATLAB is a technical computing environment for high-performance numeric computation and visualization. MATLA integrates numerical analysis, matrix, computation, signal processing, and graphics in an easy-to-useenvironment where problems and solutions are expressed just as they are written mathematically - without traditional programming.

The only data type in MATLAB is the matrix, a rectangular array of possibly complex floating-point values, which need not be dimensioned, and whose size and shape can vary dynamically.

MATLAB for UNIX, Version 7.1, available on the General-purpose UNIX Server (Logic).

2. Access to Matlab on 'Logic'

'Logic' is accessible via ssh at logic.itsc.cuhk.edu.hk. Refer to ITSC Quick Start Guide WKS003 Use of General-purpose UNIX Server (Logic) for the access details. After successful connection,

• Enter your computing id and password at the login screen;
• If you are using an X Windows interface, press the right button of the mouse and select Matlab to invoke the application. Otherwise, type matlab at system prompt.

• MATLAB is usually used interactively; when you enter single-line commands at MATLAB input prompt >>, MATLAB processes them immediately and displays the results.
  >> log(10) (any-MATLAB-statement/function)
  ans =
  (result from MATLAB)
• MATLAB can also execute sequences of MATLAB statements that are stored in the file (MATLAB calls it M-file, usually with the extension .m). You can create M-file with a text editor.
  >> fibno.m (you may type fibno and then press ? )
• To run the job in background, create an M-file and put the "quit" command as the very last line of the file. Then issue the similar command at the UNIX system prompt:
  matlab < M-file > output_file &
  (Where output_file would list any MATLAB errors which may occur)
• To quit, type "exit" or "quit":
  >> quit

  4. Matlab Statements

  MATLAB is an expressing language. Entering data or statements is simple, it is frequently of the form: variable = expression.

  >> ml = [1,2,3;4,5,6] (create a 2 x 3 matrix ml)

  m1 = (MATLAB shows the result by default)
  1 2 3
  4 5 6

• Statement ended with ; (a semicolon) stops MATLAB from displaying result:

  >> result =cos(m1*2);

• To show the value of a variable, just type the variab] name:
  >> result

• Statement ended with ... (three periods) indicates that the statement continues on the next line.
  var= 1 - 1/2 + 1/3-1/4 ...
  + 1/5- 1/6

• MATLAB has flow control statements like those found in most computer languages.
  FOR loop:                                        WHILE loop:
       for variable = expression                 while expression
            statement(s)                                      statement(s)
   end                                                 end

  IF, ELSE:                                        BREAK:
       if expression                                     break
            statement(s)                                     (terminates the
       else                                                          execution of for
            statement(s)                                     and while loops)
   and

  For the details of the functions, operators, graphics capabilities, flow control,.....provided by MATLAB, please refer to the MATLAB Reference Manual.