Introduction to MATLAB

Transcription

1 Introduction to MATLAB (MATrix LABoratory) Presented By: Dr Mostafa Elshahed Asst. Prof. 1 Upon completing this course, the student should be able to: Learn a brief introduction to programming in MATLAB. Create the MATLAB Scripts (m file) and use its help. Define the different Variables and Operations. Formulate the User-Defined Function. Discriminate between different basic flow-control. Construct the line plots, surface plots, and animations. Solve equations and curve fitting using MATLAB. Use MATLAB debugger to fix the errors. Explore Probability and Statistics commands. Utilize some MATLAB toolboxes: Simulink and SimPowerSystems. 2 1

2 Textbooks A. Gilat, MATLAB: An Introduction with Applications, 4 th Ed., John Wiley & Sons, Inc., Getting Started with MATLAB, Mathworks Inc., Assessment Lab Attendance: Grades Policy: (For Part 4 only) Quiz Project Two Labs (Two Sheets) 05 Grades 05 Grades Final Exam 30 Grades Total Grade 40 Grades 4 2

3 MATLAB R2012a (7.14) MathWorks MATLAB Is an integrated technical computing environment that combines numeric computation, advanced graphics and visualization, and a high-level programming language. High-level language of technical computing Development environment for engineers, scientists Interactive tools for design, problem solving Mathematical function libraries Graphics and data visualization tools Custom GUIs The MathWorks, Inc. External Interfaces: C, C++, Fortran, Java, COM, Excel,.NET 6 3

4 MATLAB product family MATLAB MATLAB Programming Language User-written Functions Built-in Functions Graphics 2D Graphics 3D Graphics Color & Lighting Animation Image, Audio & Video Computations Linear Algebra Data Analysis Polynomials Interpolations Solutions of ODE External Interfaces C C++ JAVA.net Micorosoft Excel Toolboxes: Collections of specialized Functions Parallel Computing Spreadsheet Parallel Computing Link Symbolic EX Toolbox (for Math Microsoft Toolbox Optimization Toolbox Math, Statistics, and Optimization MATLAB Data Acquisition Distributed Toolbox MATLAB Financial Toolbox Computational Finance Computing Bioinformatics Compiler Partial Differential System Toolbox Equation Robust Global Control Optimization Toolbox Toolbox Control System Design Server and Instrument Analysis Control MATLAB Image Signal Processing Builder Excel) Econometrics Computational Biology MATLAB NE Toolbox (for Microsoft Coder Toolbox Fixed-Point.NET Toolbox Neural Toolbox Fixed-Income Network Toolbox System Identification Toolbox Toolbox Model Predictive Control Signal Processing and Communications Toolbox Computer DSP System Vision Toolbox System HDL Coder Framework) Toolbox Code Generation and Verification SimBiology RF Toolbox Financial Statistics Toolbox Model-Based Calibration Fuzzy Derivatives Logic Toolbox Toolbox Datafeed Toolbox Toolbox Application Deployment Image Processing and Computer Image Acquisition MATLAB VisionToolbox Communications Toolbox Builder Database JA System HDL Toolbox (for Java Verifier language) Curve Fitting Toolbox Phased Array System Database Database Test Aerospace Toolbox Connectivity and Reporting Toolbox Test and and Measurement Measurement OPC Toolbox MATLAB Image Toolbox Acquisition Builder MATLAB Filter EX Toolbox Design (for Report Microsoft HDL Excel) Toolbox Vehicle Network Spreadsheet Mapping Wavelet Toolbox Toolbox Link EX Generator (for Microsoft Coder Excel) 7 Toolboxes provided By MATLAB 1. Simulink 2. Simpowersystems 3. Aerospace Simulation 4. Neural Network 5. Parallel Computing 6. Image Acquisition 7. Image processing 8. Genetic Algorithm 9. Fuzzy Logic 10. Database processing 11. Video and Image processing 12. Control System 13. Signal Processing 14. Statistics 15. Financial Toolbox 16. Curve fitting

5 Agenda Introducing MATLAB Language of technical computing Minimal MATLAB 9 Agenda Introducing MATLAB Language of technical computing Minimal MATLAB MATLAB Desktop Computing with MATLAB Array creation & working Plotting creating & visualizing Automating commands creating, saving & executing script file Conditional control statements Loop control statements Functions creating & executing a function file 10 5

6 Agenda Introducing MATLAB Language of technical computing Minimal MATLAB MATLAB Desktop Computing with MATLAB Array creation & working Plotting creating & visualizing Automating commands creating, saving & executing script file Conditional control statements Loop control statements Functions creating & executing a function file 11 MATLAB - Desktop Command Current Editor Workspace Window Directory History Window This All The commands main subwindow is where you all typed lists your write, characterized on all files variables MATLAB edit, from create, the by prompt that current the and you MATLAB save in have directory the your command generated own are script listed. window so prompt far or programs along get (>>) recorded, with in there files called type even and across m-files. size. multiple session in this window. 12 6

7 MATLAB - Desktop Help Window The main window characterized by the MATLAB command prompt (>>) 13 Scripts (MATLAB m files) Scripts are: collection of commands executed in sequence written in the MATLAB editor saved as MATLAB files (.m extension To create an MATLAB file from command-line»edit mostafa.m or click 14 7

8 Scripts (MATLAB m files) RUN 15 Agenda Introducing MATLAB Language of technical computing Minimal MATLAB MATLAB Desktop Computing with MATLAB Array creation & working Plotting creating & visualizing Automating commands creating, saving & executing script file Conditional control statements Loop control statements Functions creating & executing a function file 16 8

9 Arithmetic Operator & Their Precedence Operations Operators Examples Addition Subtraction Multiplication Right Division Left Division Exponentiation Precedence Order Operators Parentheses ( ). For nested parentheses, the innermost are executed first. Exponentiation, ^ Multiplication, *; Division, /,\ Addition, +; Subtraction, - help precedence 17 Mathematical Functions sin cos tan cot sec csc sinh cosh tanh coth sech csch Trigonometry Radian Basic Hyperbolic Inverse asin acos atan acot asec acsc Degre Basic e sind cosd tand cotd secd cscd Exponential exp log log10 log2 sqrt help <type function name> Complex abs conj imag real angle Matrix det trace rank inv expm sqrtm 18 9

10 Predefined Variables and Keywords Predefined Variables ans pi eps inf i,j NaN Keywords break case catch classdef continue else elseif end for function global if otherwise parfor persistent return spmd switch try while help <Predefined Variable Name> lookfor keyword iskeyword iskeyword( keyword ) 1 or 0 19 Useful Commands The two commands used most by Matlab users are: >>help functionname >>lookfor keyword clc Clears the command window ; Semicolon suppresses screen printing or denotes a new row in an array, Comma or Space separates elements in a row : Colon generates an array having regularly spaced elements 20 10

11 Agenda Introducing MATLAB Language of technical computing Minimal MATLAB MATLAB Desktop Computing with MATLAB Vector and Array creation & working Plotting creating & visualizing Automating commands creating, saving & executing script file Conditional control statements Loop control statements Functions creating & executing a function file 21 Variables No need for types. i.e., int a; double b; float c; All variables are created with double precision unless specified and they are matrices. >>x=5; >>x1=2; After these statements, the variables are 1x1 matrices with double precision

12 Variables Use meaningful names for variables MATLAB variable names must begin with a letter can contain any combination of letters, numbers and underscore (_) must be unique in the first 31 characters MATLAB is case sensitive: name, Name and NAME are considered different variables. Never use a variable with the same name as a MATLAB command. Naming convention: use lowercase letters 23 Managing Variables Command clear clear x y z clear all who whos save load Outcome Clears the workspace, all variables are removed from memory Clears only variables x, y, and z Clears all variables and functions from workspace Lists variables currently in the workspace Lists variables currently in the workspace with their sizes together with information about their bytes and class Save workspace variables to MAT-file >>save( MOSTAFA ) MOSTAFA.mat >>save matlab.mat Load data from MAT-file into workspace >>load( MOSTAFA ) 24 12

13 Overview Scalar of 1 X 1 Row Vector of 1 X 3 Column vector of 3 X One Dimensional Matrix of 3 X Two Dimensional Matrix of 3 X 5 3X5X Three Dimensional Matrix of 3 X 5 3X5X Creation from a known list of numbers with constant spacing by specifying the first term, the spacing, and the last term Known lists of numbers One Dimensional Array variable_name = [ type vector elements ] Two Dimensional Array variable_name = [1st row elements; 2nd row elements; 3rd row elements;... ; last row elements] 26 13

14 Creation Constant spacing : (colon operator) Creating a vector with constant spacing by specifying the first term, the spacing, and the last term: variable_name = [m:q:n] m = first term q = spacing n = last term or variable_name = m:q:n Constant spacing linspace Creating a vector with linear (equal) spacing by specifying the first and last terms, and the number of terms: variable_name = linspace(xi, xf, n) xi = first element xf = Last element n = number of elements 27 Creation a vector x = [ ] x = a matrix X = [1 2 3; 5 1 4; 3 2-1] X = transpose y = x y =

15 Creation >> x = [1 2]; y = [4 5]; z=[ 0 0] >> A = [ x y] >> B = [x ; y] C = [x y ;z] Error:??? Error using ==> vertcat CAT arguments dimensions are not consistent. 29 Array Operators Operations Operation + Addition - Subtraction * Multiplication / Division \ Left Division.* Element-by-element multiplication./ Element-by-element division.\ Element-by-element left division.^ Element-by-element power Transpose 30 15

16 Data Manipulation Address vector >> ve = [ ] ve = position or index of element 31 Data Manipulation Addressing vector : (colon operator) Addressing matrix : (colon operator) A(:,n) Refers to the elements in all the rows of column n of the matrix A. A(n,:) Refers to the elements in all the columns of row n of the matrix A. A(:,m:n) Refers to the elements in all the rows between columns m and n of the matrix A. A(m:n,:) A(m:n,p:q) Refers to the elements in all the columns between rows m and n of the matrix A. Refers to the elements in rows m through n and columns p through q of the matrix A

17 Data Manipulation Address 33 Data Manipulation The matrix indices begin from 1 (not 0 (as in C)) The matrix indices must be positive integer Given: A(-2), A(0) Error:??? Subscript indices must either be real positive integers or logicals. A(4,2) Error:??? Index exceeds matrix dimensions

18 Comment used in MATLAB % is the neglect sign for MATLAB (equivalent of // in C). Anything after it on the same line is neglected by MATLAB compiler. Sometimes slowing down the execution is done deliberately for observation purposes. You can use the command pause for this purpose >>pause %wait until any key >>pause(3) %wait 3 seconds 35 Built in Functions sort sortrows issorted 1 or 0 For vectors, SORT(X) sorts the elements of X in ascending order. For matrices, SORT(X) sorts each column of X in ascending order. >> x= 1:5 x = >> sort(x) ans = >> sort(x,'descend') ans =

19 Limit and Integration 37 Differentiation 38 19

20 Initializing with Built-in Functions zeros(n) zeros(n,m) ones(n) ones(n,m) ones(size(array)) eye(n) eye(n,m) length(vector) Length(array) size(array) zeros(size(array)) 39 Generating Vectors from functions zeros(m,n) MxN matrix of zeros x = zeros(1,3) x = ones(m,n) MxN matrix of ones rand(m,n) MxN matrix of uniformly distributed random numbers on (0,1) x = ones(1,3) x = x = rand(1,3) x =

21 Matrices Operations Given A and B: Addition Subtraction Product Transpose 41 The use of. Element Operation A = [1 2 3; 5 1 4; 3 4-1] A = x = A(1,:) x= y = A(3,:) y= b = x.* y b= c = x. / y c= d = x.^2 d= K= x^2 Error:??? Error using ==> mpower Matrix must be square. B=x*y Error:??? Error using ==> mtimes Inner matrix dimensions must agree

22 Matrix Operation(cont ) transpose( ) tril: lower triangular matrix triu: upper triangular matrix rank: show rank of matrix det: determinant of matrix diag: returns principle diagonal inv: inverse of the matrix eig: eign value(matrix must be square matrix) 43 Displaying Data/Text 44 22

23 Displaying Data/Text(cont ) 45 Thank You 46 23