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Exploring the MATLAB desktop

A quick overview of the MATLAB desktop

Command Window

The command window is the area in MATLAB where you can type MATLAB code and have it immediately execute. Try it now.

Enter the following in the command window:

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a = 1

After you hit enter, you get a response from MATLAB, as follows

result
a =

     1

…This tells you what MATLAB did. Which is assigned the value 1 to the varible a.

Workspace

The workspace helps you keep track of the variables you have assigned, in a table format. In the previous example, we created the variable a. This variable is now listed in the workspace.

image_0.png

Notice:

  • There is one row in the Workspace
  • There is information like the name of the variable (a), its value, the size, number of bytes, and class

To modify what is shown in the workspace, you can add or remove columns in the table by clicking on the upside triangle in the Workspace header to bring up the contextual menu. Under the "Choose Columns" submenu, select the following:

image_1.png

Variable Editor

Double-clicking on a variable in the workspace brings up the Variable Editor. Here, you can edit or copy variable content as if you were using a spreadsheet editor

image_2.png

Ribbon Interface

MATLAB has a context sensitive toolbar called the ribbon interface

image_3.png

  • We will often refer to this interface.
  • Notice in the image above that we have the Home tab selected

Current Folder

At launch, MATLAB opens a folder on your hard drive. You can see a reference to this folder just below the ribbon strip, in the address bar:

image_4.png

  • Here, this indicates the MATLAB drive.
  • You may see something along the lines of ~/Documents/Folder which points to a location on your hard drive

MATLAB Drive

We will use the MATLAB Drive to store course files.

The Current Folder Window displays the contents of the current folder

image_5.png

  • You can change which columns are shown in this window by clicking on the upside down triangle to bring up the contextual menu
  • Notice as you navigate to other folders, the contents displayed changes

Documentation

You can bring up the MATLAB documentation in several ways.

  1. You can enter a search term in the search bar (top right corner) image_8.png

  2. Or You can click on the ? icon (which you can find next to the search bar or in the Home tab in the ribbon strip)

  3. Or, you can type doc in the command window

Get Help
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doc

Important Preferences

The following settings that can improve the performance of MATLAB for certain tasks, especially later in the semester. Lets set them now, before we forget.

Java Heap Memory

  1. Click on the Home Tab image_10.png
  2. Select the preferences icon: image_11.png
  3. Under General: Java Heap memory, drag the slider all the way to the right

image_12.pngimage_13.png

Image Processing Toolbox settings

Use these settings

image_14.png

Live Scripts

MATLAB live scripts are interactive documents that combine MATLAB code with formatted text. These scripts are organized into sections called Code Sections. Each Section runs independently from the other Sections. You select a section by simply clicking inside that block. Once selected, the section is outlined by blue (as opposed to light gray).

Code blocks

Code blocks contain lines of MATLAB code, such as the following.

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clearvars
clc
disp('cleared')

Output location

After you execute the code in a section, you should see some output as you would in the command window. The location of this output can either be below the code block or to the right of the code block. This position is controlled by the pair of buttons on the top right side of the live script that looks like this:

image_16.png

If you hover over these buttons, you will see a tooltip string that states its function: "Show outputs on right" or "Show outputs inline".

Display Line Numbers

Under the View tab, you can select to display Line Numbers and Datatips. Do so now.

image_17.png

Code Pause

In your script, each line of code in the code block will have a line number. If you click on the number, it will become highlighted in blue as shown here:

image_20.png

This will freeze code execution at that location and interfere with your coding. If you have accidentally highlighted a number blue, simply click on the number again and the blue highlight will disappear, unfreezing execution of the code.

Debugging controls

If you a line number highlighted and execute the code block. You will enter debugging mode, which means that you manually have to advance the execution yourself.

In the Live Editor tool strip, there are three buttons you can press: Continue, Step, Stop

image_21.png

  • Continue or Step will execute the paused line of code
  • Clicking on the Stop Icon will stop the code without executing the paused line.

Comments

Sometimes you want to add a comment along with your code. The special character % indicates the start of a comment. Comments appear as green text

a = 1 % This is a comment

…notice that the comment is not executed.

Clear all

Clear your workspace and the command window by executing following commands:

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clearvars
clc

Your variables are now gone! Don't worry, we'll make more.

Games and Stuff

Ok, break time. The following commands bring up hidden easter eggs in MATLAB. Try them all by copying and pasting the following commands in the command line.

Play Sliding Puzzle
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fifteen
Play Mine Sweeper
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xpbombs
Plot a 3D Knot
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knot

Plot a Heart

Copy and paste all three lines into the command line:

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x=[-2:.001:2],y=(sqrt(cos(x)).*cos(200*x)+sqrt(abs(x))-0.7).*(4-x.*x).^0.01
figure;
plot(x,y);

Answers to Life's most pressing question

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why
Be sure to run repeatedly.