Matlab I: Geng Started - Carnegie Mellon School of ...ylataus/matlab/MatlabI.pdf · Matlab I: Geng...

MatlabI:Ge+ngStarted

DivisionofSta7s7csandScien7ficComputa7on

Instructor:YlaTausczik([email protected])

Agenda

Session1

– MatlabBackground• WhatisMatlab?History• MatlabaccessatUT

– MatlabGUIandNaviga7on– Commandlineprac7ce– Impor7ngdata– Expor7ngData

– Break

Session2

– Matlabnota7on

– Syntaxandopera7ons– Surveyoffunc7onality

• Func7ons,computa7ons

• M‐files,programming

• Simpleplo+ngprocedures

• Trivialsimula7on

– Q&A

Session1

• Introduc7on,history,accessatUT

• Ge+ngfamiliarwiththeinterface– Layout– Pulldownmenus– Windowpanels

• Crea7ngandmanipula7ngobjects– Scalars,vectors,matrices,textstrings

• Datatransport– Impor7ngintotheworkspace– Expor7ngfromtheworkspace

SlidesandFiles

h[p://homepage.psy.utexas.edu/homepage/students/Tausczik/Yla/

• PowerpointSlides• PlanetFiles

WhatisMatlab?

• MATLABderivedfromMATrixLABoratory – Applica7onkernel,e.g.,matlab‐7.6

• Computa7onalengine

• Built‐inlowlevelalgorithms(nosourcecode)

• Includesavarietyofgraphicalcapabili7es

– Suitewithcontemporaryreleases,e.g.R2008a

– Programminglanguage

WhatisMatlab?

• Designedtosolveproblemsnumerically– Par7cularlygoodformatrixopera7ons

– Usesfinite‐precisionarithme7c– Typicallyproducesapproximatedigitalsolu7ons

• Notdesignedassymboliccomputa7onsocware– DifferentfromMaple,Mathema7ca

• Easytolearnanduse– SimpliersyntaxrulesthanFortranorC

– Shorterdevelopment7meforprogramming

WhatisMatlab?

• Auxiliaries–usuallybundledwithkernel– Simulink(dynamicsystemsmodeling)– Stateflow(eventandlogic‐drivenmodeling)

• Toolboxes‐designedforspecificapplica7ons– Specializedcollec7onsofMATLABsourcefiles

• DevelopedorsupportedbyMathWorksInc.– SignalProcessing,Op7miza7on,ControlSystem,etc.

• Downloadablethirdpartyfreeware– Mul7pleprecisionarithme7c,robo7cs,etc.

Resource:h1p://www.mathworks.com/matlabcentral/

BriefHistoryofMatlab

• Originallywri[eninFortran– Author:CleveMoler,Univ.ofNewMexico

• Mathworks,Inc.foundedtofurtherdevelopit.– Incorporatedin1984– Coreiswri[eninC– Graphicalinterfaceiswri[eninJava– Runsonmanyplakorms

• Unix–Solaris,SGI,AIX,DigitalUnix• Linux• Windows• MacOS

AccesstoMatlabatUT‐Aus7n

• StudentMicrocomputerFacility(SMF)– SecondflooroftheFlawnAcademicCenter(FAC212)– MusthaveaUTEIDoranITS‐issuedaccount

h1p://www.utexas.edu/its/account/index.html

• CNSPCLab(ACA1.126)learningandinstruc=onuseonly• CNSMacLab(ACA1.124)licensedoesnotpermitresearch

• SSCservers– MatlabisinstalledontheSSCWindowsTerminalServer– ToaccessMatlabontheseserversyoumusthaveUTdiskspace

• $5peryearforUTstudentsandstaff

h1p://ssc.utexas.edu/so?ware/stat‐apps‐server

AccesstoMatlabatUT‐Aus7n

• ComputerStore(FAC109firstfloor)– Studentversion,musthaveastudentID– Fullfunc7onality,modestcost($97)

• PersonallicensefromMathWorksInc.– Specialacademicpricing– Studentversionwithdiscountpricing($99)

• h1p://www.mathworks.com/store/index.html

DefaultMatlab7DesktopGUI

GUILayout

• Windowstypeinterface

– Topnaviga7onbarwithpull‐downmenus• File• Edit• Debug• Desktop• Window• Help

– Toolbarwithicons

Naviga7onBar

• File– New(createnewm‐file,figure,variable)– ImportData

– SetPath(folders,directoriestosearch)– Preferences→CommandWindow

(numberformat,scrollbuffersize)

• Edit

– Find,Delete,Copy,Paste,etc.

Naviga7onBar

• Desktop– Chooselayoutfordisplayofwindows– Modifydefaultifdesired

• Help– LaunchMatlabHelpWindow

– Demos

DesktopNaviga7on

• FixedPlaceWindows(undockable)– TheCommandWindowrightsidepanel– TheWorkspaceWindowupperle?panel

– TheCurrentDirectoryWindowupperle?panel– TheCommandHistoryWindowlowerle?panel

• Floa7ngWindows(dockable)– TheHelpWindow– TheFigureWindow

– TheEditorWindow

CommandWindowOpera7ons

• Execu7ngcommandsatcommandline– Crea7ngobjects

>> a = 2

– Modifyingobjects >> a = a + 1

– Usingu7li7es(e.g., >> save a

• Runningprogramscripts(m‐files)

Crea7ngObjects‐Rules

• Everyobjectisamatrix– Ascalarisa1x1matrix– Arowvectorisa1xnmatrix– Acolumnvectorisanmx1matrix

• Everymatrixelementhasanumericalvalue– Non‐digitelementslinkedtoASCIIcodedigits

A→65,B→66,etc.a→97,b→98,etc.‐→45,_→95,etc

– Logicaltruthvaluesassignedtodigits(true→1,false→0)


• Squarebrackets[]areobjectdelimiters– Impliedforscalars,butcanbepresent

• Example:6or[6]– Impliedforcharacterstringrowvectors

• Example:'matlab'or['matlab']

• Acolon:istheseparatorforranges– Syntaxis<boundary>:<spacing>:<boundary>– boundaryandspacingcanbeintegerorfrac7onal– spacingcanbeincrementalordecremental– []delimiterisimplied– defaultstructureisarowvector

– Examples• 6.32:2.18:83.447or[6.32:2.18:83.447]• 100:‐2:0or[100:‐2:0]


• Separatorsforcolumnelementscommaor<space>

[1,2]→12

[345]→345

• Separatorsforrowelementssemicolonor<return>

[6;7]→67

[889→910]10


• Assigningnames– Firstcharactermustbeupperorlowercasele[er

• BasicLa7nle[ersonly(noé,ç,å,ô,ü,ñ…)– Addi7onalcharacters–le[ers,digits,orunderscore– Le[ersarecasesensi7ve– Onlythefirst31charactersrecognized– Assignmentoperatorisasingle=character

• Example:my_0bj3cT = 123.456

• Conven=ons(notenforced)– Scalar/vectornamesbeginwithalowercasele[er– Matrixnamesbeginwithanuppercasele[er

CommandWindowU7li7es

• >><command>%→'%'symbolstartscommentareaforaline

• >>clear%clearsallobjectsinworkspace

• >>clearxy%clearsvaluesofobjectsxandy

• >>clc%clearscommandwindowscrollbuffer

• >>which<filename>%findsfirstoccurrenceinsearchpath

• >>who%listsallobjectsintheworkspace

• >><command>;%semicolon→%execute,nodisplayincommandwindow

• >><control>c%stopsprogramexecu=on

• >><control>q%stopsexecu=onandexitsMatlab

CommandWindowPrac7ce

• Createascalarwithnamea– Forexample,yourhomefivedigitZIPcode

• Createarowvectorwithnameb– Forexample,elementsfromyourphonenumberdigits

• Createacolumnvectorwithnamec– Forexampleleapyearsduringyourlife

• CreatearectangularmatrixwithnameD– Variablesincolumns–forexamplebirthmonth,day,year– Casesinrows–forexamplefather,mother

• Createacharacterstringwithnamee– Forexample,yourfirstname(needstobeinsinglequotes)

WorkspaceWindowOpera7ons

• Determineproper7esofavectorormatrix– byinspec7on– usingtoolbarView > Choose Columns

• Openanobject(vector,matrix)intheArrayEditor– Changethevalueofanelement

• Makeasimpleplotofaworkspaceobject(vectorormatrix)– Lineplot,stemplot,pie(objectmusthavenumericalelements)

• CreateanewmatrixobjectandassignavalueintheArrayEditor– Lecmostworkspacetoolbaricon– Re‐nametheobjectfromthedefaultnameunnamedtoF– ConfirmaccesstonewobjectintheCommandWindow

Impor7ngData

• Directassignmentfromkeyboard

• ImportWizard– File‐>ImportData– >>uiimport

Example:>> uiimport planetsize.txt

• dlmread('filename','<delimiter>')Example:>> planets2 = dlmread('planets2.txt', ';')

• load'filename'Example:>> load 'planets3.txt'

Impor7ngData

• xlsread:ReadfilesfromExcelExample:>> planets6 = xlsread('planets6.xls')

• imread:Readgraphicsfile(severalformats)Example:>> planets7 = imread('planets7.jpg'); viewwith:>> imshow(planets7)

• Otherspecialreadfunc7ons– aviread[aviaudio/visualfiles]– textread[readfromtextfile]

– fscanf[readbyformat,similartoClanguagefunc7on]

Expor7ngData

• diary:textfileofcommandwindowoutput >> diary <filename.txt> …. >> diary off

• save:saveworkspaceobjectsortexttodisk>> save <filename>

• Binaryfile<filename>.mat

>> save <filename>.txt variablename –ascii -tabs • Textfile<filename>.txt• Matrixcolumnelementsseparatedbytabswith-tabs

Session2

• Matlabnota7on– Syntax– Opera7ons

• Surveyoffunc7onality– Func7ons,computa7ons– m‐files,programming– Simpleplo+ngprocedures

• AbrieflookatSimulink

MatlabNota7on

• Numericalvalues

– Sequenceofbase10digits• Binary,hexrepresenta7onsarecharacterstrings

– Periodasradixpointforfloa7ngpointnumbers

– Lowercaseeforpowerof10exponent

Example:>>x=123.456e‐07

→x=0.0000123456[not(123.456)*(2.71828,,,)‐7]

MatlabNota7on

• Complexnumbers– iandjini7allysettothesquarerootof‐1

Imaginaryparthasiorjappended

(1+1i)isasinglecomplexexpression

(1+1*i)isasumofoneandcurrentvalueofi

• Matrices– Rectangulararraysofelements

• Indexedbyrow,thenbycolumn

Example:>> A = [ a(1,1) a(1,2); a(2,1) a(2,2)]

MatlabNota7on

• Booleanlogicals(Bernoullivariables)– TruthValues

1fortrue;0forfalse

– Primarylogicsymbols&logicalAND==logicalequal|logicalinclusiveOR~logicalNOT

– Compoundlogicsymbols<=>=~=xor(p,q)logicalexclusiveOR

Equivalentto(p&~q)|(~p&q)

MatlabNota7on

• Separatorsanddelimiters[]squarebrackets‐‐vectorandmatrixdelimiters{}curlybrackets‐‐celldelimiter()parentheses

• Groupingincompoundexpressions• Vectorandmatrixelementindices• Func7onargument

:colon‐‐indexrangeseparator;semicolon‐‐matrixrowseparator<space>matrixcolumnseparator,comma‐‐matrixindex,func7onargumentseparator‐‐rowvectorelementseparator''singlequotes‐‐demarca7onofcharacterstrings

MatlabOpera7ons

• Arithme7cOpera7ons–precedingperiod– Example–arithme7cmatrixmul7plica7on(.*)– Arithme7cOpera7onsareelementbyelement

a11a12a13b11b12b13c11c12c13

a21a22a23.*b21b22b23=c21c22c23a31a32a33b31b32b33c31c32c33

Note:c23=(a23*b23)

MatlabOpera7ons

• Matrix/Vectoropera7ons–noprecedingperiod– Example:matrixmul7plica7on(*)

– Innerproductof(lecsiderow)with(rightsidecolumn)

a11a12a13b11b12b13c11c12c13

a21a22a23*b21b22b23=c21c22c23a31a32a33b31b32b33c31c32c33

Note:c23=(a21*b13)+(a22*b23)+(a23*b33)

MatlabOpera7ons

• Valueassignmentopera7on=assignsavaluetotheantecedent<return>acerexpressionassignsvaluetoans

• Unarymatrixandelementopera7ons.'Matrixtranspose

– Rowsandcolumnsreversedwithsameordering

'Matrixcomplextranspose– Signsofimaginarypartsofelementsreversed

.^Raisingmatrixelementstoapower^Raisingamatrixtoapower

MatlabOpera7ons

• Binarymatrixandelementopera7ons+matrixorelementaddi7on‐matrixorelementsubtrac7on.*elementbyelementmul7plica7on*matrixmul7plica7on./elementbyelementdivision/rightmatrixdivision

• sameasrightmul7plica7onbydivisorinverse

\lecmatrixdivision• Sameaslecmul7plica7onbydivisorinverse

SurveyofMatlabFunc7onality

Computa7onandProgramming GraphicsandDataVisualiza7on Introduc7ontoSimulink

Compu7ngandProgramming

• Computa7ons– Combina7onsofelementaryopera7ons

– Built‐inconstants• Scalars:pi(numericalπ);i,j(√‐1)

• Matrices:zeros(m,n);ones(m,n);eye(m,n)

– Built‐infunc7ons• Numerical:sin;cos;exp;log

• Logical:isprime;isreal


• Batchcommands(macros)canbeputinscripts

• Scriptsarecreatedintheeditorwindow File>New>M‐File

• Scriptsaresavedinm‐fileswitha‘.m’extension

• Codeissequen7allis7ngofcommandsSameasstepbystepinthecommandwindow


• Elementaryflowcontrolinscripts

– Condi7onalif..elseif..[elseif..elseif..]else

– Loopfor

– Condi7onalLoopwhile


• ifcommand

if{condi=on}commandblock;elseif{condi=on}commandblock;

…

elseif{condi=on}commandblock;

elsecommandblock;end;


• forloop

for{indexrange}commandblock;end;

• whilecondi7onalloop

while{condi=on}commandblock;end;


• OpenanewM‐filefromFile‐>New

• Createsomenewobjectsinyourcode– Ascalarfromafunc7on,e.g.,x=exp(1);– Aarowvectorrange,e.g.,g=[0:1:100];– Afunc7onvector,e.g.,h=sin(g./10);– A3x3func7onmatrix,

• e.g.,J=log([111213;141516;171819]);– Aflowcontrolstructure

• e.g.,ifelementofhisposi7vesquareitsvalueotherwisecubeitsvalue

• SavetheM‐file,e.g.,asmyfile.m

• RunmyfileintheCommandWindow


• Convertyourfunc7onrowvectortoacolumn• Example:>> k = h.'

• Makeacompoundexpression• Example:>>m = x + x.^3 - log(x)

• Operateonamatrix:• Example:>>N=inv(J)%producestheinverseofthematrix

GraphicsandDataVisualiza7on

• Makea2‐Dplot– Example:plot(g,h)

– Customizeplotbyedi7nginFigureWindow• Changeaxisproperty• Changelinestyleandcolor• Changebackgroundcolor• Addaxislabelsand7tle


• Makea3‐Dlineplot– Create3same‐lengthvectors,e.g.,

>>p = [0:0.1:10];%rangevector>> q = p./2;%samelengthrangevector>> r = sin(p).*cos(q);%func=onvector

– Plotthe3‐Dcurve–Example:>> plot3(p,q,r)

– Rotatethecurvein3‐Dusingtoolbaricon


• Makea3‐Dsurfaceplot– Createamatrixoffunc7onvalues

Example:>> S = (sin(p))'*(cos(q));

– Plotasurfaceofmatrixvalues>> surf(S)%polygonalfacets>> mesh(S)%wiremesh

– Rotatetheplotin3‐Dusingtoolbaricon

Introduc7ontoSimulink

• Asimula7ontoolfordynamicsystems

• SimulinklibraryBrowser:– Collec7onofsources,systemmodules,sinks

System Input Output


• Openanewmodelwindow– ExpandSimulinkonMatlabStartbu[on– SelectLibraryBrowser– ClickonNewModelicon(upperlec)

• Draginsources,operators,andsinks– Chooseasource,e.g.,SineWave

• Editaparameter,e.g.,Amplitude

– Chooseasink,e.g.,Scope– Chooseanoperator,e.g.,ConZnuous‐>DerivaZve


• Connectthemodelcomponents– Arrowsfromsourcestooperators• Outputfromonesourcecanbeinputforanother

– Arrowsfromoutputstosinks(e.g.,scopes)

• Runthesimula7on– OpenScopewindows– ClickontheRunicon– Observethescopedisplay

ThanksforComing

• Addi7onalSSCMatlabShortCourses

– MatlabII‐‐Compu7ngandProgramming• Tutorialsec7ons5and6

• TutorialsOnline– h[p://ssc.utexas.edu/socware/socware‐tutorials#matlab

Survey

h[ps://www.surveymonkey.com/s/LRJ6WJK

Matlab I: Geng Started - Carnegie Mellon School of ...ylataus/matlab/MatlabI.pdf · Matlab I: Geng...

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