Doug's MATLAB Video Tutorials

Project Euler on Cody

Doug — Fri, 03 Feb 2012 18:34:18 +0000

I am a big fan of Project Euler. There are a series of math and programming problems there that people often use in honing their programming skills. Traditionally, there is one correct integer answer for each problem. I have been modifying the problems and posting them on Cody such that there can be a test suite of several inputs with several outputs. This fits more into the model of Cody.

Go learn MATLAB by doing on these time-tested problems. My expectation is to make explanatory video for some of the problems. If they prove popular, I will keep adding them to the site.

Cody for learning MATLAB

Doug — Fri, 27 Jan 2012 21:41:34 +0000

Cody is a newly released feature of MATLAB Central. It allows you to hone your MATLAB skills by solving short MATLAB code challenges, live on the web. You will get instant feedback about your code’s performance and then find out if other solutions were able to work in different ways. This gives you a chance to learn new techniques in MATLAB. Go take a look, you might even want to make some of your own challenges for others to solve.

Understanding the display method for a cell

Doug — Thu, 19 Jan 2012 15:56:36 +0000

A MATLAB user wanted to get rid of the quote marks from a string in a cell array. This was not needed because they only appeared there due to the display method for a cell.

How to do a matrix reshape by ‘blocks’

Doug — Tue, 10 Jan 2012 18:11:47 +0000

This week’s video covers a non-standard way of reshaping a matrix. Instead of using the reshape function, this kind of matrix manipulation must be done with for loops. This matrix reshape operation treats submatrices within the original matrix as a unit. I suspect there are many other ways of doing this, and would love to hear about them in the comments.

Plotting multiple lines on a figure in MATLAB

Doug — Tue, 20 Dec 2011 15:18:40 +0000

This MATLAB graphics tutorial shows you how you can plot multiple lines on the same plot.

MATLAB tip: Use one command per line

Doug — Fri, 09 Dec 2011 18:38:49 +0000

This is a common programming pattern that I see with new MATLAB users: They put more than one command per line in MATLAB file. This can make it harder to visually take in a file, and because profiler and error messages give information back based on the line number this practice will often hide the source command if they are nested or placed two on a line.

Welcome to Sean from Answers

Doug — Fri, 02 Dec 2011 18:51:11 +0000

I wanted to take this week to point out what a great resource MATLAB Answers is and to also welcome one of the most prolific contributors on that site to his new role as an applications engineer here at MathWorks. Welcome Sean.

The concept behind MATLAB Answers is that the User Community is generous enough to support each other as we all learn more about MATLAB. It creates a forum for people to get quick, correct answers to well-formatted questions in a searchable form. If you have not already asked and answered questions here, I recommend you try it. I frequently use it to solve my own programming problems. In fact one of the core functions of the MATLAB programming contest was developed by the community here. I did not actually need the help , I just liked using the great resource to confirm the algorithm… Yeah, that is the story!

Passing data between GUIDE callbacks without globals in MATLAB

Doug — Wed, 23 Nov 2011 15:23:03 +0000

Very often MATLAB users want to share data between different callbacks that they have in their MATLAB GUIs. This video shows a technique that is applicable for when the data being shared is already stored in the state of the GUI. Examples of data that is stored in the state of the GUI includes the state (checked or unchecked) of a checkbox or the string that is held in an edit box. This programming pattern is also good for having a variety of UIcontrols update the GUI in the same way.

If you are looking to share data between callbacks that is not stored in the state of the GUI, then this very old video should help. It shows you how to use GETAPPDATA and SETAPPDATA to share data in a MATLAB GUI.

Expression evaluation in MATLAB

Doug — Fri, 11 Nov 2011 17:22:42 +0000

MATLAB is constantly evaluating expressions and expressions within expressions. A lot of MATLAB users do not think about this, or the implications. Simple examples of using a vector as the index into a for loop instead of one that is dynamically created (1:10 for example) is shown. Also, the use of a variable as an input to a function expecting a string is shown.

Contest is on! Vines

Doug — Wed, 02 Nov 2011 19:32:46 +0000

Hey Contest fans, the new MATLAB contest is on. I am expecting this to be a great contest, several of us worked specifically on coming up with a good test suite for you to solve. By “good test suite”, I mean one that will be difficult, but fun to solve. Since I am not clever enough to ever win one of these contests, I get to have the fun of anticipating what kinds of solvers will be used, and then design test cases that will frustrate those efforts! You are welcome! :)

Enjoy!

Doug and the contest designers!