Essential MATLAB for Engineers and Scientists

Transcription

1 Essential MATLAB for Engineers and Scientists Third edition Brian D. Hahn and Daniel T. Valentine ELSEVIER AMSTERDAM BOSTON HEIDELBERG LONDON NEW YORK OXFORD PARIS SAN DIEGO SAN FRANCISCO SINGAPORE SYDNEY TOKYO Butterworth-Heinemann is an imprint of Elsevier B

2 Preface to the third edition xvii PART I ESSENAALS 1 1 Introduction Using MATLAB The MATLAB desktop Sample program Cut and paste Saving a program: script files How a program works 21 2 MATLAB fundamentals Variables and the workspace Variables Case sensitivity The workspace Adding commonly used constants to the workspace Arrays: vectors and matrices Initializing vectors: explicit Iists Initializing vectors: the colon Operator inspace Transposing vectors Subscripts Matrices Capturing output Vertical motion under gravity Operators, expressions and statements Numbers Data types Arithmetic operators Precedence of operators The colon operator The transpose operator 39

3 Contents Arithmetic operations on arrays Expressions Statements Statements, commands and functions VectQrization of formulae Output disp format Scale factors Repeating with for Square roots with Newton's method Factorials! Limit of a sequence The basic for construct for in a single line More general for Avoid for loops by vectorizing! A common mistake: for less loops! Decisions The one-line if statement The if - else construct The one-line if - else statement elseif Logical operators Multiple ifs versus elseif Nested ifs Vectorizing ifs? swit ch Complex numbers More on input and output fprintf Output to a disk file with fprintf General file I/O Saving and loading data Odds 'n ends Variables, functions and scripts with the same name The input statement Shelling out to the operating system More Help functions Programming style 76 3 Program design and aigorlthm development Computer program design process Projectile problem example 89

4 Contents 3.2 Other examples of structure plans Quadratic equation 3.3 Structured programming with functions MATLAB functions & *data import-export Some common functions *Importing and exporting data The load and save commands Exporting text (ASCII) data I mporting text (ASCII) data Exporting binary data The Import Wizard Low-Ievel File I/O functions Other import/export functions Logical vectors Examples Discontinuous graphs Avoiding division by zero Avoiding infinity Counting random numbers Rolling dice Logical operators Operator precedence Danger Logical operators and vectors Subscripting with logical vectors Logical functions Using any and all Logical vectors instead of elseif ladders Mattees of numbers & arrays of strings Matrices A concrete example Creating matrices Subscripts Transpose The colon operator Duplicating rows and columns: tiling Deleting rows and columns Elementary matrices *Specialized matrices Using MATLAB functions with matrices Manipulating matrices 152 vii

5 Array (element-by-element) operations on matrices Matrices and for Visualization of matrices Vectorizing nested fors: loan repayment tables Multidimensional arrays Matrix operations Matrix multiplication Matrix exponentiation Other matrix functions *Strings Assignment Input Strings are arrays Concatenation of strings ASCII codes, double and char f pr int f of strings Comparing strings Other string functions *Two-dimensional strings *eval and text macros Error trapping with eval and lasterr eval with try... catch IntroductIon to graphics 7.1 Basic 2-D graphs Labels Multiple plots on the same axes Line styles, markers and color Axis limits Multiple plots in a figure: subplot figure, clf and cla Graphical Input Logarithmic plots Polar plots Plotting rapidly changing mathem tical tuneions: fplot The property editor D plots plot Animated 3-D plots with comet Mesh surfaces Contour plots Cropping a surface with NaNs Visualizing vector fields Visualization of matrices viii

6 7.2.8 Rotation of 3-D graphs Other cool graphics functions Loops Determinate repetition with for Binomial coefficient Update processes Nested f ors Indeterminate repetition with while A guessing game The while statement Doubling firne of an investment Prime numbers Projectile trajectory break and continue Menus Errors and Malis Syntax errors lasterr Pitfalls and surprises Incompatible vector sizes Name hiding Other pitfalls for the unwary Errors in logic Rounding error Trapping and generating errors Fonetim efiles Some examples Inline objects: harmonic oscillators Function M-files: Newton's method again Basic rules Subfunctions Private functions P-code files lmproving M-file performance with the profiler Function handles Command/function duality Function name resolution Debugging M-files Debugging a 'script Debugging a function Recursion 246 ix

7 Ateeteeägememene Conto 11 Vectors as arrays & *advanced data structures Update processes Unit time steps Non-unit time steps Using a function Exact solution Frequencies, bar charts and histograms A random walk Histograms *Sorting Bubble Sort MATLAB's sort *Structures *Cell arrays Assigning data to cell arrays Accessing data in cell arrays Using cell arrays Displaying and visualizing cell arrays *Classes and objects *More graphics Handle Graphics Getting handles Graphics object properties and how to change them A vector of handles Graphics object creation functions Parenting Positioning figures Editing plots Plot edit mode Property Editor Animation Animation with Handle Graphics Color etc Colormaps Color of surface plots Truecolor Lighting and camera Saving, printing and exporting graphs Saving and opening figure files Printing a graph Exporting a graph 290

8 13 *Graphical User Interfaces (GU1s) Basic structure of a GUI A first example: getting the time Exercise Newton again Axes an a GUI Adding color to a button 302 PART II APPLICATIONS Dynamical systems Cantilever beam Electric current Free fall Projectile with friction Simulation Random number generation Seeding rand Spinning coins Rolling dice Bacteria division A random walk Traffic flow Normal (Gaussian) random numbers *More matrices Leslie matrices: population growth Markov processes A random walk Linear equations MATLAB's solution The residual Overdetermined systems Underdetermined systems III conditioning Matrix division Sparse matrices *Introduction to numerical methods Equations Newton's method The Bisection method 362 xi

9 f zero roots Integration The Trapezoidal rule Simpson's rule quad Numerical differentiation diff First-order differential equations Euler's method Example: bacteria growth Alternative subscript notation A predictor-corrector method Linear ordinary differential equations (LODEs) Runge-Kutta methods A single differential equation Systems of differential equations: chaos Passing additional parameters to an ODE solver A partial differential equation Heat conduction Other numerical methods 385 Appendix A: Syntax quick reference 390 A.1 Expressions 390 A.2 Function M-files 390 A.3 Graphics 390 A.4 if and switch 391 A.5 for and while 392 A.6 Input/output 393 A.7 load/save 393 A.8 Vectors and matrices 393 Appendix B: Operators 395 Appendix C: Command and functionquick reference 396 C.1 General purpose commands 397 C.1.1 Managing commands 397 C.1.2 Managing variables and the workspace 397 C.1.3 Files and the operating system 397 C.1.4 Controlling the Command Window 398 C.1.5 Starting and quitting MATLAB 398 C.2 Logical functions 398 xii

10 C.3 Language constructs and debugging 398 C.3.1 MATLAB as a programming language 398 C.3.2 Interactive input 399 C.4 Matrices and matrix manipulation 399 C.4.1 Elementary matrices 399 C.4.2 Special variables and constants 399 C.4.3 Time and date 400 C.4.4 Matrix manipulation 400 C.4.5 Specialized matrices 400 C.5 Mathematical functions 400 C.6 Matrix functions 401 C.7 Data analysis 402 C.8 Polynomial functions 402 C.9 Function functions 402 C.10 Sparse matrix functions 402 C.11 Character string functions 403 C.12 File I/O functions 403 C.13 Graphics 403 C D 403 C D 404 C.13.3 General 404 Appendix D: ASCII character codes 405 Appendix E: Solutions to selected exercises 406 Index 421