Basics of MATLAB and Beyond

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whosName Size Bytes Classa 1x1 8 double arrayb 1x10 80 double arraystr 1x5 10 char arrayGrand total is 16 elements using 98 bytes>> aa =1>> bb =1 2 3 4 5 6 7 8 9 10>> strstr =helloTo save the data as readable text use the -ascii switch:save saved_data_text -asciiIn this case the ‘.mat’ extension is not appended to the file name. Theascii format is best kept for simple cases where your data is in the formof a matrix (or vector or scalar). For example, in this case we have savedthe variables a, b, and c in a file that has the following contents:1.0000000e+001.0000000e+00 2.0000000e+00 3.0000000e+00 ...1.0400000e+02 1.0100000e+02 1.0800000e+02 ...The first line is the variable a, the second line is the variableb = [1 2 ... 10], and the third line is the string str = ’hello’ convertedto its corresponding ascii values:>> double(str)ans =104 101 108 108 111If you try to load this data using the load command you will get an errormessage because the lines have different numbers of values. To load anascii file like this, you’ll have to write your own loading function usingthe functions getl etc. described in the next section. If you save anascii matrix, however, you can load it in again without difficulty:>> clear>> q = spiral(3)c○ 2000 by CRC Press LLC
q =7 8 96 1 25 4 3>> save saved_data_text -ascii>> clear>> load saved_data_text>> whosName Size Bytes Classsaved_data_text 3x3 72 double arrayGrand total is 9 elements using 72 bytes>> saved_data_textsaved_data_text =7 8 96 1 25 4 3The data is loaded as a variable with the same name as the file name(no information about variable names are stored in the file).30.2 Other FormatsYou may be presented with some data written by another piece of softwarethat you want to load into matlab. In this case you have thefollowing options:1. You can write a translation program in another language (C orfortran for example) that reads in the data and then writes it toanother file that can be read into matlab—that is, a mat-file.2. You can write a matlab-callable program (mex-file) that readsin the data and returns appropriate variables in the matlabworkspace. This is a good option if you already have code to readin the data.3. You can use one of the functions for reading in standard file formatsfor images, sounds, spreadsheets, 11 and so on. These are:dlmreadwk1readimreadRead ascii data file.Read spreadsheet (WK1) file.Read image from graphics file (JPEG, TIFF, etc.).11 For Lotus123 spreadsheets you can use the functions wk1read and wk1write. Ifyou use Microsoft Excel, the MathWorks’ Excel Link product allows direct communicationbetween Excel and matlab. For example, Excel can be used as a front-endfor matlab; you can call matlab functions or graphics routines directly from Excel,or you can access your Excel spreadsheet data directly from matlab.c○ 2000 by CRC Press LLC
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BASICS OFMATLAB®and Beyondc○ 200
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Library of Congress Cataloging-in-P
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typing pwd (print working directory
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ContentsIBasics of MATLAB1 First St
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20 Time-Frequency Analysis21 Line A
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39Answers to Exercises (Part I)40 A
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Set → Getting Started with MATLAB
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1.5 The Colon OperatorTo generate a
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matlab will recall the last command
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a = zeros(2,3)a =0 0 00 0 0>> b = o
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[a a(a)]ans =1 2 3 1 4 74 5 6 2 5 8
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a + bans =11 3344 6677 993.8 Transp
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4.2 Adding PlotsWhen you issue a pl
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x = [[1 2 3 4]’ [2 3 4 5]’ [3 4
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4.7 AxesSo far we have allowed matl
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v =1122>> v*uans =1 2 0 11 2 0 12 4
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max returns a vector containing the
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s = 100*spiral(3)s =700 800 900600
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We can plot the surface z as a func
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The contour function plots the cont
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m = gray(8);colormap(m)imagesc(1:10
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hold onplot3(x(ind),y(ind),z(ind),
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z = 5*ones(3,3)z =5 5 55 5 55 5 5>>
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contour(x,y,z,30);You may have noti
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variables that are local to themsel
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SwitchThe basic form of a switch st
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i =i =123136Vectorised Codematlab i
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9.1 MATLAB FormatTo save all the va
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11 StartupEach time you start matla
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Where p i is the population for yea
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NaNs by leaving them off the plot.
Page 64 and 65: clfpolar(t,gdb)In this case you mus
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Page 68 and 69: the periodograms of the blocks, and
Page 70 and 71: plot(y(1:1000))axis([0 1000 -5 5])z
Page 72 and 73: comet(x,y)(You can get a three-dime
Page 74 and 75: By clicking within the panner box a
Page 76 and 77: x = linspace(-1,1,8192);Fs = 1000;y
Page 78 and 79: 23.3 Graphical Object Hierarchymatl
Page 80 and 81: Now we need to get the handles of a
Page 82 and 83: Beyond the BasicsPreludeThis part o
Page 84 and 85: clfgplot(A,[x y])axis off(Try zoomi
Page 86 and 87: str =you’re the one>> str = ’
Page 88 and 89: strrep(str,’go’,’am’)ans =I
Page 90 and 91: ans =3.14159e+100Some additional te
Page 92 and 93: eval(str)v =1 2 3 4 5The eval(str)
Page 94 and 95: Inline objects, like every other ma
Page 96 and 97: a(1,1) = {[1 2 3]}a =[1x3double]or>
Page 98 and 99: t = {’help’ spiral(3) ; eye(2)
Page 101 and 102: meteo.Temperatureans =24ans =19.000
Page 103 and 104: 3 >> a = [1 2 ;4 5 6;7 8 9]a =1 2 3
Page 105 and 106: [x,y] = meshgrid(1:5,1:3)x =1 2 3 4
Page 107 and 108: ans(:,:,2) =999And to sum over “p
Page 109 and 110: An Application of RGB ImagesTo see
Page 111 and 112: You can see that over the 8 time st
Page 113: name>> staff(2,1,2).name(5:9)ans =B
Page 117 and 118: fid = fopen(’asc.dat’);The fope
Page 119 and 120: display and the enclosed area is th
Page 121 and 122: MarkerEdgeColor = auto(and so on)In
Page 123 and 124: text(-.7,f(-.7),’f(X)’)But we h
Page 125 and 126: plt(x,f(x/2),’--’)Let us try ca
Page 127 and 128: Example: findobjThe findobj command
Page 129 and 130: 3. Add the property you want to set
Page 131 and 132: is numbered from top to bottom. The
Page 133 and 134: axis ijUsually images like this do
Page 135 and 136: 32.2 Tick Marks and Labelsmatlab’
Page 137 and 138: clfaxes(’pos’,[.2 .1 .7 .4])x =
Page 139 and 140: property to [0 top] in the call to
Page 141 and 142: object’s HorizontalAlignment and
Page 143 and 144: the required symbols. The m-file ti
Page 145 and 146: 1. Use graphical elements that serv
Page 147 and 148: uicontrol(’Callback’,’ezplot(
Page 149 and 150: uicontrol(’Pos’,[110 280 60 19]
Page 151 and 152: ’String’,’0.5’,’Style’,
Page 153 and 154: function exradio(action)if nargin =
Page 155 and 156: fail. One place to put variables th
Page 157 and 158: 34.7 Fast DrawingFor fast drawing o
Page 159 and 160: controlled by guide and which are a
Page 161 and 162: InvertHardcopy: [ {on} | off ]Paper
Page 163 and 164: Another option is to use an image f
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yur is the y coordinate of the uppe
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\end{center}\caption{This is the fi
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x 294x1 ...y 294x1 ...z 294x1 ...Gr
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diagram. Such a triangular grid can
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xt = x([1 9 10 1]);yt = y([1 9 10 1
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x = [0 0 .5 0.5 .5 1 11 .5 .5 .5];y
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fac2 = [1 2 61 6 31 4 61 6 5];The r
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t = linspace(0,2*pi,20);x = cos(t);
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N = 20;dt = 2*pi/N;t = 0:dt:(N-1)*d
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colouring of the sphere itself. To
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material dullThe default is materia
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time taken by this routine to calcu
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first row of a by taking the column
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38.3 Debuggingmatlab has a suite of
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10: y = linspace(ycentre - L,ycentr
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We change variables:p ′ = C + Bx.
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Exercise 6 (Page 59)You can generat
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33 ! 36 $ 39 ’ 42 * 45 - 48 034 "
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R = 1; N = 200;[x,y] = meshgrid(lin
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(The plot might take a few seconds
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% Reproduce the layers at the diffe
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