1 / 142

ELE 532 – Signals and Systems Fall 2007 MATLAB Tutorial

ELE 532 – Signals and Systems Fall 2007 MATLAB Tutorial. Raymond Phan Distributed Multimedia Computing Research (DMCR) Lab Ryerson University – EPH 237 rphan@ee.ryerson.ca. http://www.ee.ryerson.ca/~rphan/ele532/MATLABTutorial.ppt. Outline of Tutorial – (1). Introduction Getting Started

shalin
Download Presentation

ELE 532 – Signals and Systems Fall 2007 MATLAB Tutorial

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. ELE 532 – Signals and SystemsFall 2007MATLAB Tutorial Raymond Phan Distributed Multimedia Computing Research (DMCR) Lab Ryerson University – EPH 237 rphan@ee.ryerson.ca http://www.ee.ryerson.ca/~rphan/ele532/MATLABTutorial.ppt

  2. Outline of Tutorial – (1) • Introduction • Getting Started • Variables and Starting Basics • Vectors and Matrices • Basic Operations • Script Files • Function Script Files

  3. Outline of Tutorial – (2) • Flow Control • Basic Graphics Commands • Other Useful Commands • Final Words

  4. Introduction – (1) • So… what the hell is MATLAB and what’s it all about? • MATLAB: MATrix LABoratory • Created in 1970 by a dude named Cleve Moler • Was (and still is) used extensively at Stanford University and the University of New Mexico • Why? To make calculating the following things a lot easier! • Matrix Theory • Linear Algebra • Numerical Analysis

  5. Introduction – (2) • MATLAB is selected as a numerical analysis tool over languages like C and Java because: • Very EASY programming language • Powerful graphics capabilities • Very sleek and interactive interface • Great for general scientific and engineering computation • Later in your courses, you’re going to start to use this heavily, especially in: • ELE 639: Control Systems • ELE 792: Digital Signal Processing • … any signal processing and controls course in 4th year

  6. Outline of Tutorial – (1) • Introduction • Getting Started • Variables and Starting Basics • Vectors and Matrices • Basic Operations • Script Files • Function Script Files

  7. Getting Started – (1) • Where can I find and use MATLAB? • Method #1: On the EE undergraduate network labs: • ENG 406, 407, 408 and 409 • Log onto an EE undergraduate terminal • A) Go to Applications – Accessories – Terminal and type in ‘matlab’ (without the quotes) • B) Go to Applications – Math – MATLAB 2007a

  8. Getting Started – (2) • Method #2: If you don’t feel like using the computers at school, you can install your own copy of MATLAB on your PC or laptop • There are many ways to obtain your own copy: • Buy a student version at the Ryerson Bookstore • Obtain a trial version online via: http://www.mathworks.com • “Borrow” from a friend • Version of MATLAB needed for these labs: MATLAB 7.0 and up • NOTE!: You MUST have the Java Runtime Environment (JRE) installed on your system • At LEAST 5.0 and up • MATLAB uses the JRE as a backbone to run the whole application

  9. Getting Started – (3) • What happens next!? • MATLAB Interface: >> means it’s ready for input from you

  10. Outline of Tutorial – (1) • Introduction • Getting Started • Variables and Starting Basics • Vectors and Matrices • Basic Operations • Script Files • Function Script Files

  11. Variables and Basic Commands – (1) • One GREAT thing about MATLAB: • MATLAB is a programming language that is dynamically typed… what does this mean? • You can declare variables and initialize them without specifying what type they are • MATLAB automatically figures this out for you, or you can choose to manually override the type • Example: • C or Java way: int nikhil = 1, double jenny = 2 • MATLAB way: nikhil = 1, jenny = 2

  12. Variables and Basic Commands – (2) • When you want to assign something to a variable, use the = sign • When you assign something to a variable, MATLAB initializes & automatically declares it • Guidelines for variable names: • All must be single words, no spaces • Must begin with a letter, numbers or the underscore character ( _ ) • Variable names are case sensitive • i.e nikhil is NOT the same as Nikhil • i.e muffin is NOT the same as mUFfin • Names can be up to 19 characters in length

  13. Variables and Basic Commands – (3) • Some valid variable names: • voltage • valueOfR1 • Ron_and_Mauro • _Alan2007_ • Some invalid variable names (why are these invalid?): • 123 • value of R1 • 3v • X#*()$#$!!!

  14. Variables and Basic Commands – (4) • Left panel: Current Directory / Workspace • A) Shows you directory structure to access working directory (more on this later) • B) Shows you all of the variables that have been created and can be accessed • Right: Command Prompt • Enter commands and variable declarations here • Commands without a semicolon ( ; ) echo your command to screen • Commands with a semicolon suppress that output

  15. Variables and Basic Commands – (5) • Can enter commands either: • One at a time: The end of each command, press ENTER (carriage return) • Multiple commands in one line: • Suppress echoing: Use semicolons to separate each command on the line • Enable echoing: Use commas ( , ) to separate each command on the line • Typing in a variable by itself and pressing ENTER will redisplay the variable • Entering a value, pressing ENTER, and not assigning it to anything, the value will be automatically assigned to a variable called ans (answer)

  16. Variables and Basic Commands – (6)

  17. Variables and Basic Commands – (7) • who command: Shows you all of the variables created by you • You can also check the workspace as well • clear command: Clears all of the variables shown in the workspace, and you start from scratch • clc command: Flushes the command prompt • Variables will still be in the workspace, but it clears the command prompt screen

  18. Variables and Basic Commands – (8)

  19. Variables and Basic Commands – (9) • Can also declare complex numbers too: • Can add, subtract, multiply and divide • You can use i or j to declare complex numbers • Of course… you can also add, subtract, multiply and divide normal numbers too! • Too lazy to make a slide for it • However, we’ll get into addition, subtraction, multiplication and division in another way later

  20. Variables and Basic Commands – (10)

  21. Variables and Basic Commands – (11) • Command History window: Used to keep track of the commands you ran recently • You can alsodouble click on any of the commandsto re-run them again • You can also pressthe up & down keysto cycle throughthe commands aswell in the commandprompt

  22. Outline of Tutorial – (1) • Introduction • Getting Started • Variables and Starting Basics • Vectors and Matrices • Basic Operations • Script Files • Function Script Files

  23. Vectors and Matrices – (1) • Unless otherwise defined, MATLAB treats ALL variables as 2D matrices… how is this possible? • Arrays and Vectors: N x 1 or 1 x N matrix • Single value: 1 x 1 matrix • Why does MATLAB decide to handle it this way? • You’ll see later that handling variables as matrices makes things A LOT faster and easier to work with

  24. Vectors and Matrices – (2) • How do you declare a vector / array in MATLAB? • C or Java way: int a[4] = {1, 2, 3, 4}; • MATLAB way: • a = [1 2 3 4] – row vector • Spaces mean to move to the next column • a = [1 2 3 4].’ – (.’ operator means to transpose a vector) - column vector • a = [1;2;3;4] - column vector • Semicolon means to move to the next row • You do not have to specify how big the vector is first before you make it • Beauty of dynamically typed languages! • MATLAB automatically figures out how big it is and you go from there

  25. Vectors and Matrices – (3) • How do I access elements in a vector / array? • C or Java way: • int jenny = a[0]; • MATLAB way: • jenny = a(1); • NOTE!: • No square brackets when accessing an element! Use round brackets! • Elements do not start at index 0, they start at index 1!

  26. Vector and Matrices – (4)

  27. Vector and Matrices – (5) • How do I create a matrix in MATLAB? • C or Java way: int a[4][4] = {{1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10, 11, 12}, {13, 14, 15, 16}}; • MATLAB way: • #1: a = [1 2 3 4; 5 6 7 8; 9 10 11 12; 13 14 15 16]; • #2: a = [1 2 3 4;5 6 7 8;9 10 11 12;13 14 15 16];

  28. Vector and Matrices – (6) • How do I access elements in a matrix? • C or Java way: • int alan = a[2][3]; • MATLAB way: • alan = a(3,4); • What’s the difference here? • No separate brackets for each dimension • Comma is used to separate the dimensions • All indices to access arrays are offset by 1! • Remember: 1st parameter is the row, 2nd parameter is the column

  29. Vector and Matrices – (7) • Here’s something to mess you up… how do I access a range of values in a matrix? • Suppose I had a matrix already created called ray • How do I get all of the elements in the 1st row? • C or Java way: • int i;for(i = 0; i < 4; i++) ray[i] = a[0][i]; • This is a pain in the butt!... There’s gotta be an easier way to do this!

  30. Vectors and Matrices – (8) • MATLAB way: • ray = a(1, 1:4); • ray = a(1, :); • What’s the difference here?! • NO for loop! • The colon ( : ) operator is used to access a range of values • There is a more general use for this, but we’ll get into this later • 1 : 4 means a range from 1 through 4 for a dimension • : by itself means give me all possible values in a dimension • Doing 1 : 4 in the 2nd parameter means give me columns 1 through 4 • Doing : in the 2nd parameter means give me all of the columns!

  31. Vectors and Matrices – (9)

  32. Vectors and Matrices – (10) • Some more examples: • sally = a(2,3); • sally = a(1:3,3:4); • sally = a(:, 1:3); • sally = a(2:4,:); • 1st line: Access 2nd row, 3rd column element, and assign it to sally • 2nd line: Get a matrix with elements between rows 1 – 3, and columns 3 – 4 and assign this to sally • 3rd line: Get a matrix with elements between columns 1 – 3 and give me every possible row, and assign this to sally • 4th line: Get a matrix with elements between rows 2 – 4 and give me every possible column, and assign this to sally

  33. Vectors and Matrices – (11) • Here’s a curve ball! • Joe = a(:,:); • Joe = a; • What does this mean? Copy the entire matrix, a, and assign it to Joe • You can also do the 2nd line too. It’s exactly the same meaning

  34. Vectors and Matrices – (12) • Example Time! • 1) How do we define M in MATLAB syntax? • 2) How do we execute a), b), c) and d)?

  35. Vectors and Matrices – (13)

  36. Vectors and Matrices – (14)

  37. Vectors and Matrices – (15) • Example #2!

  38. Vectors and Matrices – (16) • In other words, with matrices A, B and C, make me a matrix that looks like this! • What do we need to do? • How do we define matrices A, B and C? • How do we create M?

  39. Vectors and Matrices – (17)

  40. Vectors and Matrices – (18) • MATLAB has a really cool way of making vectors / arrays where consecutive elements are uniformly spaced • Example: • Ray = 0 : 0.1 : 1.0; • This generates a vector / array with 11 elements, such that • Ray = [0 0.1 0.2 0.3 … 1.0];

  41. Vectors and Matrices – (19) • General Form: • new_array = first_value : increment : last_value • Make note of the colons ( : )! • first_value: The first value in the new vector / array • last_value: The last value in the new vector / array • increment: The step size • If you don’t include this value, it is automatically assumed to be 1

  42. Vectors and Matrices – (20) • Examples: • jenny = 0 : 2 : 10; • eman = 3 : 3 : 30; • ron = 1 : 10; • mauro = 2.0 : -0.2 : 0.4; • 1st line: Creates a 6 element vector • jenny = [0 2 4 6 8 10]; • 2nd line: Creates a 10 element vector • eman = [3 6 9 12 … 27 30];

  43. Vectors and Matrices – (22) • 3rd line: Creates an 10 element vector • ron = [1 2 3 … 9 10]; • 4th line: Creates a 8 element vector • mauro = [2.0 1.8 … 0.6 0.4]; • Pretty easy don’t you think!? • Remember how I told you about that colon operator?... Well, here you go! • To do this in C and Java, it requires a bit more work.

  44. Vectors and Matrices – (23) • Some useful matrix and vector / array commands • eye(n): Creates an n x nidentity matrix

  45. Vectors and Matrices – (24) • Some useful matrix and vector / array commands • ones(n,m): Creates an n x m matrix full of ones • ones(1,n) or ones(n,1): Creates an array / vector that has n elements, full of ones

  46. Vectors and Matrices – (25) • Some useful matrix and vector / array commands • zeros(n,m): Creates an n x m matrix full of zeros • zeros(1,n) or zeros(n,1): Creates an array / vector that has n elements, full of zeros

  47. Vectors and Matrices – (26) • Last important note: • MATLAB evaluates expressions to the right of the equals sign first • After, it assigns this result to the variable to the left of the equals sign • Here’s an example:sum = 2;sum = sum + 3; • What happens here? sum gets assigned the value of 2 first, then it gets added with 3, and stored back into sum • … and that’s it for this section… whew!

  48. Outline of Tutorial – (1) • Introduction • Getting Started • Variables and Starting Basics • Vectors and Matrices • Basic Operations • Script Files • Function Script Files

  49. Basic Operations – (1) • Let’s assume the following: • A and B: Are matrices or vectors / arrays of compatible dimensions • Assume they can be added, subtracted, multiplied and divided properly • n is a scalar (single value number) • Here’s a table that provides a good summary of all of the basic operations you can perform on matrices and vectors / arrays

  50. Basic Operations – (2) • Here, the elements in the matrices or vectors / arrays can be real or complex • Addition and Subtraction will just add and subtract two matrices normally • For vectors, each corresponding component gets added or subtracted

More Related