MATLAB Notes for Professionals Programming and Problem Solving (Chahdi, Othmane) (Z-Library)

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Contents About ............................................................................................................. ...................................................................... 1 Chapter 1: Getting started with MATLAB Language ................................................................................... 2 Section 1.1: Indexing matrices and arrays ................................................................................................................... 3 Section 1.2: Anonymous functions and function handles .......................................................................................... 8 Section 1.3: Matrices and Arrays ........................................................................................................................... ..... 11 Section 1.4: Cell arrays ........................................................................................................................... ..................... 13 Section 1.5: Hello World ........................................................................................................................... .................... 14 Section 1.6: Scripts and Functions ........................................................................................................................... ... 14 Section 1.7: Helping yourself ........................................................................................................................... ............ 16 Section 1.8: Data Types ........................................................................................................................... .................... 16 Section 1.9: Reading Input & Writing Output ............................................................................................................ 19

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Chapter 2: Initializing Matrices or arrays ....................................................................................................... 21 Section 2.1: Creating a matrix of 0s ........................................................................................................................... 21 Section 2.2: Creating a matrix of 1s ........................................................................................................................... 21 Section 2.3: Creating an identity matrix .................................................................................................................... 21 Chapter 3: Conditions ............................................................................................................. .................................. 22 Section 3.1: IF condition ........................................................................................................................... .................... 22 Section 3.2: IF-ELSE condition ........................................................................................................................... ......... 22 Section 3.3: IF-ELSEIF condition ........................................................................................................................... ...... 23 Section 3.4: Nested conditions ........................................................................................................................... ........ 24 Chapter 4: Functions ............................................................................................................. ................................... 27 Section 4.1: nargin, nargout ........................................................................................................................... ............. 27

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Chapter 5: Set operations ............................................................................................................. ......................... 29 Section 5.1: Elementary set operations ..................................................................................................................... 29 Chapter 6: Documenting functions ............................................................................................................. ....... 30 Section 6.1: Obtaining a function signature .............................................................................................................. 30 Section 6.2: Simple Function Documentation ........................................................................................................... 30 Section 6.3: Local Function Documentation ............................................................................................................. 30 Section 6.4: Documenting a Function with an Example Script ............................................................................... 31 Chapter 7: Using functions with logical output ........................................................................................... 34 Section 7.1: All and Any with empty arrays ............................................................................................................... 34 Chapter 8: For loops ............................................................................................................. .................................... 35 Section 8.1: Iterate over columns of matrix .............................................................................................................. 35 Section 8.2: Notice: Weird same counter nested loops ........................................................................................... 35 Section 8.3: Iterate over elements of vector ............................................................................................................ 36

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Section 8.4: Nested Loops ........................................................................................................................... ............... 37 Section 8.5: Loop 1 to n ........................................................................................................................... .................... 38 Section 8.6: Loop over indexes ........................................................................................................................... ....... 39 Chapter 9: Object-Oriented Programming .................................................................................................... 40 Section 9.1: Value vs Handle classes ......................................................................................................................... 40 Section 9.2: Constructors ........................................................................................................................... ................. 40 Section 9.3: Defining a class ........................................................................................................................... ............ 42 Section 9.4: Inheriting from classes and abstract classes ...................................................................................... 43 Chapter 10: Vectorization ............................................................................................................. .......................... 47 Section 10.1: Use of bsxfun ........................................................................................................................... ............... 47 Section 10.2: Implicit array expansion (broadcasting) [R2016b] ............................................................................ 48 Section 10.3: Element-wise operations ...................................................................................................................... 49 Section 10.4: Logical Masking

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........................................................................................................................... .......... 50 Section 10.5: Sum, mean, prod & co .......................................................................................................................... 51 Section 10.6: Get the value of a function of two or more arguments .................................................................... 52 Chapter 11: Matrix decompositions ............................................................................................................. ....... 53 Section 11.1: Schur decomposition ........................................................................................................................... ... 53 Section 11.2: Cholesky decomposition ....................................................................................................................... 53 Section 11.3: QR decomposition ........................................................................................................................... ....... 54 Section 11.4: LU decomposition ........................................................................................................................... ....... 54 Section 11.5: Singular value decomposition .............................................................................................................. 55 Chapter 12: Graphics: 2D Line Plots ............................................................................................................. ...... 56 Section 12.1: Split line with NaNs ........................................................................................................................... ...... 56 Section 12.2: Multiple lines in a single plot ................................................................................................................ 56

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Section 12.3: Custom colour and line style orders ................................................................................................... 57 Chapter 13: Graphics: 2D and 3D Transformations ................................................................................... 61 Section 13.1: 2D Transformations ........................................................................................................................... .... 61 Chapter 14: Controlling Subplot coloring in MATLAB ............................................................................... 64 Section 14.1: How it's done ........................................................................................................................... ............... 64 Chapter 15: Image processing ............................................................................................................. ................. 65 Section 15.1: Basic image I/O ........................................................................................................................... ........... 65 Section 15.2: Retrieve Images from the Internet ...................................................................................................... 65 Section 15.3: Filtering Using a 2D FFT ....................................................................................................................... 65 Section 15.4: Image Filtering ........................................................................................................................... ............ 66 Section 15.5: Measuring Properties of Connected Regions ..................................................................................... 67

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Chapter 16: Drawing ............................................................................................................. ..................................... 70 Section 16.1: Circles ........................................................................................................................... ........................... 70 Section 16.2: Arrows ........................................................................................................................... .......................... 71 Section 16.3: Ellipse ........................................................................................................................... ........................... 74 Section 16.4: Pseudo 4D plot ........................................................................................................................... ........... 75 Section 16.5: Fast drawing ........................................................................................................................... ............... 79 Section 16.6: Polygon(s) ........................................................................................................................... ................... 80 Chapter 17: Financial Applications ............................................................................................................. ........ 82 Section 17.1: Random Walk ........................................................................................................................... .............. 82 Section 17.2: Univariate Geometric Brownian Motion .............................................................................................. 82 Chapter 18: Fourier Transforms and Inverse Fourier Transforms .................................................... 84

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Section 18.1: Implement a simple Fourier Transform in MATLAB ........................................................................... 84 Section 18.2: Images and multidimensional FTs ...................................................................................................... 85 Section 18.3: Inverse Fourier Transforms .................................................................................................................. 90 Chapter 19: Ordinary Di erential Equations (ODE) Solvers ................................................................. 92 Section 19.1: Example for odeset ........................................................................................................................... ..... 92 Chapter 20: Interpolation with MATLAB .......................................................................................................... 94 Section 20.1: Piecewise interpolation 2 dimensional ................................................................................................ 94 Section 20.2: Piecewise interpolation 1 dimensional ................................................................................................ 96 Section 20.3: Polynomial interpolation ................................................................................................................... 101 Chapter 21: Integration ............................................................................................................. ............................. 105 Section 21.1: Integral, integral2, integral3 ................................................................................................................ 105 Chapter 22: Reading large files ............................................................................................................. ........... 107

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Section 22.1: textscan ........................................................................................................................... ..................... 107 Section 22.2: Date and time strings to numeric array fast .................................................................................. 107 Chapter 23: Usage of `accumarray()` Function ......................................................................................... 109 Section 23.1: Apply Filter to Image Patches and Set Each Pixel as the Mean of the Result of Each Patch ........................................................................................................................... .................................................. 109 Section 23.2: Finding the maximum value among elements grouped by another vector ................................ 110 Chapter 24: Introduction to MEX API ............................................................................................................. 111 Section 24.1: Check number of inputs/outputs in a C++ MEX-file ........................................................................ 111 Section 24.2: Input a string, modify it in C, and output it ...................................................................................... 112 Section 24.3: Passing a struct by field names ........................................................................................................ 113 Section 24.4: Pass a 3D matrix from MATLAB to C ............................................................................................... 113 Chapter 25: Debugging ............................................................................................................. ............................. 116 Section 25.1: Working with Breakpoints .................................................................................................................. 116 Section 25.2: Debugging Java code invoked by MATLAB ................................................................................... 118

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Chapter 26: Performance and Benchmarking ........................................................................................... 121 Section 26.1: Identifying performance bottlenecks using the Profiler ................................................................. 121 Section 26.2: Comparing execution time of multiple functions ............................................................................ 124 Section 26.3: The importance of preallocation ...................................................................................................... 125 Section 26.4: It's ok to be `single`! ........................................................................................................................... . 127 Chapter 27: Multithreading ............................................................................................................. .................... 130 Section 27.1: Using parfor to parallelize a loop ...................................................................................................... 130 Section 27.2: Executing commands in parallel using a "Single Program, Multiple Data" (SPMD) statement ........................................................................................................................... .................................................. 130 Section 27.3: Using the batch command to do various computations in parallel ............................................. 131 Section 27.4: When to use parfor ........................................................................................................................... . 131 Chapter 28: Using serial ports ............................................................................................................. .............. 133 Section 28.1: Creating a serial port on Mac/Linux/Windows ............................................................................... 133 Section 28.2: Choosing your communication mode

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.............................................................................................. 133 Section 28.3: Automatically processing data received from a serial port .......................................................... 136 Section 28.4: Reading from the serial port ............................................................................................................. 137 Section 28.5: Closing a serial port even if lost, deleted or overwritten ............................................................... 137 Section 28.6: Writing to the serial port .................................................................................................................... 137 Chapter 29: Undocumented Features ............................................................................................................ 138 Section 29.1: Color-coded 2D line plots with color data in third dimension ........................................................ 138 Section 29.2: Semi-transparent markers in line and scatter plots ....................................................................... 138 Section 29.3: C++ compatible helper functions ...................................................................................................... 140 Section 29.4: Scatter plot jitter ........................................................................................................................... ...... 141 Section 29.5: Contour Plots - Customise the Text Labels ...................................................................................... 141 Section 29.6: Appending / adding entries to an existing legend ......................................................................... 143 Chapter 30: MATLAB Best Practices ............................................................................................................. .. 145 Section 30.1: Indent code properly .......................................................................................................................... 145 Section 30.2: Avoid loops ...........................................................................................................................

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.............. 146 Section 30.3: Keep lines short ........................................................................................................................... ....... 146 Section 30.4: Use assert ........................................................................................................................... ................ 147 Section 30.5: Block Comment Operator ................................................................................................................. 147 Section 30.6: Create Unique Name for Temporary File ........................................................................................ 148 Chapter 31: MATLAB User Interfaces ............................................................................................................. . 150 Section 31.1: Passing Data Around User Interface ................................................................................................. 150 Section 31.2: Making a button in your UI that pauses callback execution .......................................................... 152 Section 31.3: Passing data around using the "handles" structure ........................................................................ 153 Section 31.4: Performance Issues when Passing Data Around User Interface ................................................... 154 Chapter 32: Useful tricks ............................................................................................................. .......................... 157 Section 32.1: Extract figure data ........................................................................................................................... ... 157 Section 32.2: Code Folding Preferences ................................................................................................................. 158 Section 32.3: Functional Programming using Anonymous Functions ................................................................. 160 Section 32.4: Save multiple figures to the same .fig file

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........................................................................................ 160 Section 32.5: Comment blocks ........................................................................................................................... ...... 161 Section 32.6: Useful functions that operate on cells and arrays ......................................................................... 162 Chapter 33: Common mistakes and errors ................................................................................................. 165 Section 33.1: The transpose operators .................................................................................................................... 165 Section 33.2: Do not name a variable with an existing function name ............................................................... 165 Section 33.3: Be aware of floating point inaccuracy ............................................................................................. 166 Section 33.4: What you see is NOT what you get: char vs cellstring in the command window ........................ 167 Section 33.5: Undefined Function or Method X for Input Arguments of Type Y ................................................. 168 Section 33.6: The use of "i" or "j" as imaginary unit, loop indices or common variable .................................... 169 Section 33.7: Not enough input arguments ............................................................................................................ 172 Section 33.8: Using `length` for multidimensional arrays ...................................................................................... 173 Section 33.9: Watch out for array size changes .................................................................................................... 173 Credits ............................................................................................................. ............................................................... 175 You may also like ............................................................................................................. ......................................... 177

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About Please feel free to share this PDF with anyone for free, latest version of this book can be downloaded from: https://goalkicker.com/MATLABBook This MATLAB® Notes for Professionals book is compiled from Stack Overflow Documentation , the content is written by the beautiful people at Stack Overflow. Text content is released under Creative Commons BY-SA, see credits at the end of this book whom contributed to the various chapters. Images may be copyright of their respective owners unless otherwise specified This is an unofficial free book created for educational purposes and is not affiliated with official MATLAB® group(s) or company(s) nor Stack Overflow. All trademarks and registered trademarks are the property of their respective company owners The information presented in this book is not guaranteed to be correct nor accurate, use at your own risk Please send feedback and corrections to web@petercv.com

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Chapter 1: Getting started with MATLAB Language Version Release Release Date 1.0 1984-01-01 2 1986-01-01 3 1987-01-01 3.5 1990-01-01 4 1992-01-01 4.2c 1994-01-01 5.0 Volume 8 1996-12-01 5.1 Volume 9 1997-05-01 5.1.1 R9.1 1997-05-02 5.2 R10 1998-03-01 5.2.1 R10.1 1998-03-02 5.3 R11 1999-01-01 5.3.1 R11.1 1999-11-01 6.0 R12 2000-11-01 6.1 R12.1 2001-06-01 6.5 R13 2002-06-01 6.5.1 R13SP2 2003-01-01 6.5.2 R13SP2 2003-01-02 7 R14 2006-06-01 7.0.4 R14SP1 2004-10-01 7.1 R14SP3 2005-08-01 7.2 R2006a 2006-03-01 7.3 R2006b 2006-09-01 7.4 R2007a 2007-03-01 7.5 R2007b 2007-09-01 7.6 R2008a 2008-03-01 7.7 R2008b 2008-09-01 7.8 R2009a 2009-03-01 7.9 R2009b 2009-09-01 7.10 R2010a 2010-03-01

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7.11 R2010b 2010-09-01 7.12 R2011a 2011-03-01 7.13 R2011b 2011-09-01 7.14 R2012a 2012-03-01 8.0 R2012b 2012-09-01 8.1 R2013a 2013-03-01 8.2 R2013b 2013-09-01 8.3 R2014a 2014-03-01 8.4 R2014b 2014-09-01 8.5 R2015a 2015-03-01 8.6 R2015b 2015-09-01 9.0 R2016a 2016-03-01 9.1 R2016b 2016-09-14 9.2 R2017a 2017-03-08 See also: MATLAB release history on Wikipedia .

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Section 1.1: Indexing matrices and arrays MATLAB allows for several methods to index (access) elements of matrices and arrays: Subscript indexing - where you specify the position of the elements you want in each dimension of the matrix separately. Linear indexing - where the matrix is treated as a vector, no matter its dimensions. That means, you specify each position in the matrix with a single number. Logical indexing - where you use a logical matrix (and matrix of true and false values) with the identical dimensions of the matrix you are trying to index as a mask to specify which value to return. These three methods are now explained in more detail using the following 3- by-3 matrix M as an example: >> M = magic ( 3 ) ans = 8 1 6 3 5 7 4 9 2 Subscript indexing The most straight-forward method for accessing an element, is to specify its row-column index. For example, accessing the element on the second row and third column: >> M( 2 , 3 ) ans = 7 The number of subscripts provided exactly matches the number of dimensions M has (two in this example). Note that the order of subscripts is the same as the mathematical convention: row index is the first. Moreover, MATLAB indices starts with 1 and not 0 like most programming languages. You can index multiple elements at once by passing a vector for each

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coordinate instead of a single number. For example to get the entire second row, we can specify that we want the first, second and third columns: >> M( 2 , [ 1 ,2 ,3 ]) ans = 3 5 7 In MATLAB, the vector [ 1 , 2 , 3 ] is more easily created using the colon operator, i.e. 1 :3 . You can use this in indexing as well. To select an entire row (or column), MATLAB provides a shortcut by allowing you just specify :. For example, the following code will also return the entire second row >> M( 2 , :) ans = 3 5 7 MATLAB also provides a shortcut for specifying the last element of a dimension in the form of the end keyword. The end keyword will work exactly as if it was the number of the last element in that dimension. So if you want all the columns from column 2 to the last column, you can use write the following: >> M( 2 , 2 :end ) ans = 5 7 Subscript indexing can be restrictive as it will not allow to extract single values from different columns and rows; it will extract the combination of all rows and columns. >> M([ 2 ,3 ] , [ 1 ,3 ]) ans = 3 7 4 2 For example subscript indexing cannot extract only the elements M( 2 ,1 ) or M( 3 ,3 ) . To do this we must consider linear indexing. Linear indexing MATLAB allows you to treat n-dimensional arrays as one-dimensional arrays when you index using only one dimension. You can directly access the first element: >> M( 1 ) ans = 8

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Note that arrays are stored in column-major order in MATLAB which means that you access the elements by first going down the columns. So M( 2 ) is the second element of the first column which is 3 and M( 4 ) will be the first element of the second column i.e. >> M( 4 ) ans = 1 There exist built-in functions in MATLAB to convert subscript indices to linear indices, and vice versa: sub2ind and ind2sub respectively. You can manually convert the subscripts (r,c) to a linear index by idx = r + ( c1 ) *size ( M,1 ) To understand this, if we are in the first column then the linear index will simply be the row index. The formula above holds true for this because for c == 1 , ( c1 ) == 0 . In the next columns, the linear index is the row number plus all the rows of the previous columns. Note that the end keyword still applies and now refers to the very last element of the array i.e. M( end ) == M( end , end ) == 2 . You can also index multiple elements using linear indexing. Note that if you do that, the returned matrix will have the same shape as the matrix of index vectors. M( 2 :4 ) returns a row vector because 2 :4 represents the row vector [ 2 , 3 , 4 ] : >> M( 2 :4 ) ans = 3 4 1 As another example, M([ 1 ,2 ;3 ,4 ]) returns a 2-by-2 matrix because [ 1 ,2 ;3 ,4 ] is a 2-by-2 matrix as well. See the below code to convince yourself: >> M([ 1 ,2 ;3 ,4 ]) ans = 8 3 4 1 Note that indexing with : alone will always return a column vector: >> M( :) ans = 8 3 4