Some useful Matlab tips

• Excellent tutorial by Matt Dunham, covers basics as well as advanced topics like object oriented programming (2008a version), calling Java, new functions like bsxfun that can help you avoid repmats, etc.

• Official mathworks tutorial on using matlab, includes interactive and video-based tutorials

• Getting started in Matlab, pdf file from the Mathworks.

• Matlab for psychologists, a good tutorial even for non-psychologists!

• Ian Mitchell's (UBC CS) guide

• Lots of matlab tutorials.

• comp.soft-sys.matlab newsgroup

• Matlab Central is an excellent repository of free Matlab software.

• Matlab programming style guide

• Speedup tricks by Tom Minka

• Making stand alone programs or dll's with matlab and Deploying Programs

Some useful tips

• Calling R from Matlab

• The matlab emacs mode is extremely useful if you use emacs as your editor. (Emacs runs on unix and windows.)

• Type matlab -nosplash to prevent the annoying splash screen from appearing whenever you startup. Use matlab -nodesktop to run matlab in text-only mode.

• When using unix, I run matlab in text mode (matlab -nodesktop) inside an emacs shell buffer, so I can cut and paste easily between my source code and the command line, without using the mouse. (If anyone knows how to do this in Windows, please let me know! The problem seems to be that matlab cannot run inside a windows cmd window.)

• Type format compact when you start your Matlab session. This will make the output format take less space.

• Create a startup.m file in your matlab directory, and add any commands that you want executed automatically whenever you start up Matlab. In Windows, this file will probably be called C:\matlab\bin\startup.m or maybe C:\matlab\R12\work\startup.m. In matlab 7, it goes in C:\matlab701\toolboxes\local\startup.m or C:\MATLAB701\work\startup.m. In Unix, this file should be called ~username/matlab/startup.m. For example, my Windows startup.m file reads as follows

  addpath C:\murphyk\matlab\BNT
  add_BNT_to_path
  format compact
  dbstop if error
  dbstop if warning
  

• process_options.m written by Mark Paskin is an extremely useful function for handling multiple optional named arguments eg

  [a,b] = f(x, y, 'arg1', 55, 'arg3', 66)
  
  [a,b] = function f(x, y, varargin)
  [a1, a2, a3] = process_options(varargin{:}, ...
    'arg1', 1, 'arg2', 2, 'arg3', 3);
  

  Will pass in named arguments arg1 and arg3 to f; the remaining arguments will be set to their default values ( in this case, arg2 gets set to 2).

• vec(ndx) = 1 assigns all the elements of 'vec' specified by the index array 'ndx' the value 1 (parallel assignment).

• ... is a continuation character, needed if an input line is split across more than one screen width. It MUST be preceeded by a space.

• If C is a cell array, C(ndx) is a cell array with elements specified by ndx, but C{ndx} is a comma separated list of the values inside the specified cells. Example: C={1,2,3} so C{1} = 1 but C(1) = {1}.

Help

• help foo will print the documentation for function 'foo'.

• lookfor foo will find all functions that mention 'foo' in their documentation (comments at the beginning of the file).

• which foo will tell you the full filename of the function that implements 'foo'. If foo is an overloaded name (i.e., a class method), type which classname/foo.

• type foo will display the file 'foo'. e.g. type(which('pinv'))

Debugger, profiler, etc

• Tips on using the symbolic debugger

• Type dbstop if error and dbstop if warning when you start your Matlab session. This will pop you into the debugger if there is an error/ warning, e.g., if an assertion is violated. dbstack will tell you where the error occured. dbup/dbdown ley you change stack frames inside the debugger. dbquit gets you out of the debugger. Matlab supports full symbolic debugging and interactive execution.

• Put a keyboard command in the source code at a point where you want to enter interactive mode. This lets you inspect variables etc. Use dbcont to continue with the program execution.

• Matlab 7 mlint is good for finding errors in your code.

• tic starts a clock and toc stops one. This can be used to time code.

• In Matlab 5.3 and later, profile on turns on the profiler. In older versions, you can only profile a specific function, using profile fn_name. After running the function, type profile report or in version 6.5 profview.

Filing system

• Use textread or dlmread to read in a text (eg csv) file. In Matlab 7, textscan is good for reading in formatted files.

• Directories that start with @ represent classes. This convention is required.

• addpath foo adds directory 'foo' to the search path. In matlab 6.1, you can use addpath(genpath('foo')) to add foo and all its subdirectories to your path. (The matlab 6.0 version of genpath was buggy.) To hide certain directories (eg old versions of code), put them in a directory beginning with the '@' symbol - matlab will skip these (since it thinks they are class directories). Otherwise if you have 2 functions with the same name, the one that occurs most recently on the path will hide/mask the other. You can also use genpathKPM to skip certain directories with names like 'Old', 'CVS', etc.

• Use fullpath(dirname, filename) to make full filenames in an operating system independent way (eg in windows, this becomes 'dirname\filename' whereas in unix this becomes 'dirname/filename') Use fileparts to parse open a filename.

• Filenames are not allowed to have - (minus sign) in them: use _ (underscore) instead.

• clear functions will clear the cache of out of date versions of files. (Use clear classes for class constructors.)

Graphics

• plotyy shows 2 vertical axes on the left and right

• Use sfigure.m (written by Daniel Eaton) instead of figure, so that matlab won't steal the focus when running in the background. (Otherwise everytime matlab plots something, it will pop to the foregroudn, and interupt whatever you were doing.)

• In matlab 7, use iptsetpref('imshowInitialMagnification','fit') to make imshow show pictures at the size of the window. By default, imshow resizes the figure window so that every image pixel gets 1 screen pixel.

• Use exportfig script to make nice looking figures for your papers (so the lines are thick enough, the fonts large enough, etc).

Objects/ classes