Introduction to Programming I - Hacettepe Üniversitesibbm101/fall17/lectures/...About BBM 101...

Lecture#01– CourseIntroduction,WhatisComputation

Erkut Erdem,AykutErdem&AydınKaya//Fall2017 1

BBM101IntroductiontoProgrammingI

DrawingofAnalyticalEngine.Image: UniversityofCambridge

LectureOverview• Courseintroduction

• Whatiscomputation

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Disclaimer:Muchofthematerialandslidesforthislecturewereborrowedfrom— RuthAnderson,MichaelErnstandBillHowe’sCSE140class

CourseInformation

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CourseStaff

• Instructors: AykutErdem,Erkut Erdem,AydınKaya

• TeachingAssistants:

– Necva Bölücü– SelmaDilek

– Selim Yılmaz

– Cemil Zalluoğlu 4

DonothesitatetoaskTAsforhelp!

AboutBBM101• Thiscourseteachescoreprogrammingconceptswithanemphasisondatamanipulationtasks fromscience,engineering,andbusiness

• Goal bytheendofthesemester:Givenadatasource andaproblemdescription,youcanindependentlywriteacomplete,usefulprogramtosolvetheproblem

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• BBM103IntroductiontoProgrammingLaboratoryI− Studentswillgainskillstoapplytheconceptstorealworldproblems

LearningObjectives

• Computationalproblem-solving–Writingaprogramwillbecomeyour“go-to”solutionfordataanalysistasks.

• BasicPythonandCproficiency– Includingexperiencewithrelevantlibrariesfordatamanipulation,scientificcomputing,andvisualization.

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WhatThisCourseisnot• A“skillscourse”inPython/C– …thoughyou’llbecomeproficientinthebasicsofthePython/Cprogramminglanguage

– …andyouwillgainexperiencewithsomeimportantPython/Clibraries

• A“project”course– theassignmentsare“real,”butareintendedtoteachspecificprogrammingconcepts

• A“softwareengineering”course– Programmingisthestartingpointofcomputerscienceandsoftwareengineering

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Imagecredit:Google+user

Communication

• Website: http://web.cs.hacettepe.edu.tr/~bbm101/

• Seethewebsiteforalladministrativedetails

• Readthehandoutsandrequiredtexts,before thelecture

• Takenotes!

• FollowthecourseinPiazzahttps://piazza.com/hacettepe.edu.tr/fall2017/bbm101

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TextBooks• ThePythonTutorial,availablefromthePythonwebsite.

– ThisisgoodforexplainingthenutsandboltsofhowPythonworks.

• IntroductiontoComputationandProgrammingUsingPython,SecondEdition,JohnV.Guttag,MITPress,August2016

• ThinkPython,2ndedition– Freelyavailableonlinein HTML and PDF.– Alsoavailableforpurchaseasaprintedbook,butdon'tbuythe

firstedition.– Thisbookintroducesmoreconceptualmaterial,motivating

computationalthinking.

• Thereisan interactiveversionof“HowtoThinkLikeaComputerScientist” (thefirsteditionof“ThinkPython”),whichletsyoutypeandrunPythoncodedirectlywhilereadingthebook.

• TheCProgrammingLanguage,2ndEdition,BrianKernighanandDennisRitchie,PrenticeHall,1988

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GradingPolicy

• GradingforBBM101willbebasedon– twomidtermexam(25+30=55%)

– afinalexam(40%)

– classparticipation(5%)

• InBBM103,thegradingwillbebasedon– fiveassignments(75%)

– asetofquizzes(25%)(Yourlowest2quizgradeswillbedropped.)

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AcademicIntegrity• Honestworkisrequiredofascientistorengineer.

• Collaborationpolicyonthecourseweb.Readit!– Discussionispermitted.– Carryingmaterialsfromdiscussionisnotpermitted.

– Everythingyouturninmustbeyourownwork.• Citeyoursources,explainanyunconventionalaction.

– Youmaynotviewothers’work.

– Ifyouhaveaquestion,ask.

• Wetrustyoucompletely.

• Butwehavenosympathyfortrustviolations– norshouldyou!

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HowtoSucceed• Noprerequisites

• Non-predictorsforsuccess:– Pastprogrammingexperience– Enthusiasmforgamesorcomputers

• Programminganddataanalysisarechallenging

• Everyoneofyoucansucceed– Thereisnosuchthingasa“bornprogrammer”

– Workhard– Followdirections– Bemethodical– Think beforeyouact– Tryonyourown,thenaskforhelp– Startearly

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Python

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PythonVersion

• WhateverIDEyouchoosetoworkwith,alwayssticktoPythonversion3.5.2

• Always usethisversiontocodeyourassignments.

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IntegratedDevelopmentEnvironment(IDE)• Therearemany!

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OurRecommendation:PyCharm

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ComputerProgramming

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“It’sagreattimetobeadatageek.”-- RogerBarga,MicrosoftResearch

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“Thegreatestmindsofmygenerationaretryingtofigureouthowtomakepeopleclickonads”

-- JeffHammerbacher,co-founder,Cloudera

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AllofScienceisReducingtoComputationalDataManipulationOldmodel:�Querytheworld� (Dataacquisitioncoupledtoaspecifichypothesis)Newmodel:�Downloadtheworld� (Dataacquisitionsupportsmanyhypotheses)– Astronomy:High-resolution,high-frequencyskysurveys(SDSS,LSST,PanSTARRS)– Biology:labautomation,high-throughputsequencing,– Oceanography:high-resolutionmodels,cheapsensors,satellites

40TB/2nights

~1TB/day100sofdevices

Example:AssessingTreatmentEfficacy

Zipcodeofclinic

Zipcodeofpatient

numberoffollowupswithin16weeksaftertreatmentenrollment.

Question:Doesthedistancebetweenthepatient’shomeandclinicinfluencethenumberoffollowups,andthereforetreatmentefficacy?

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PythonProgramtoAssessTreatmentEfficacy# This program reads an Excel spreadsheet whose penultimate# and antepenultimate columns are zip codes.# It adds a new last column for the distance between those zip# codes, and outputs in CSV (comma-separated values) format.# Call the program with two numeric values: the first and last# row to include. # The output contains the column headers and those rows.

# Libraries to useimport randomimport sysimport xlrd # library for working with Excel spreadsheetsimport timefrom gdapi import GoogleDirections

# No key needed if few queriesgd = GoogleDirections('dummy-Google-key')

wb = xlrd.open_workbook('mhip_zip_eScience_121611a.xls')sheet = wb.sheet_by_index(0)

# User input: first row to process, first row not to processfirst_row = max(int(sys.argv[1]), 2)row_limit = min(int(sys.argv[2]+1), sheet.nrows)

def comma_separated(lst):return ",".join([str(s) for s in lst])

headers = sheet.row_values(0) + ["distance"]print comma_separated(headers)

for rownum in range(first_row,row_limit):row = sheet.row_values(rownum)(zip1, zip2) = row[-3:-1]if zip1 and zip2:

# Clean the datazip1 = str(int(zip1))zip2 = str(int(zip2))row[-3:-1] = [zip1, zip2]# Compute the distance via Google Mapstry:

distance = gd.query(zip1,zip2).distanceexcept:

print >> sys.stderr, "Error computing distance:", zip1, zip2

distance = ""# Print the row with the distanceprint comma_separated(row + [distance])# Avoid too many Google queries in rapid successiontime.sleep(random.random()+0.5)

23linesofexecutablecode!

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Source:Brookings

Thevalueofacomputerscienceeducation

Slidecredit:code.org

Somestatistics(fromU.S.)

Computingjobsarethe#1sourceofnewwagesintheUnitedStates

500,000currentopenings:Thesejobsareinevery industryandevery state,andthey’reprojectedtogrowattwicetherate

ofallotherjobs.



TheSTEM*problemisincomputerscience:

Sources:BureauofLaborStatistics,NationalCenterforEducationStatistics

71%ofall newjobsin

STEMareincomputing

8%ofSTEMgraduates

areincomputerscience

*STEM=Science,Technology,Engineering,andMathSlidecredit:code.org


WhatisComputation?

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Computerscienceisjustaboutlearningtechnology

Somemaythink:


Computerscienceisjustaboutlearningtechnology

Computerscienceisaboutlogic,problemsolving,andcreativity

Somemaythink:


WhatisKnowledge?• Declarativeknowledge

– Axioms(definitions)

– Statementsoffact

“yisthesquarerootofxifandonlyify*y=x”doesnothelptofindthesquareroot!

WhatisKnowledge?(cont’d.)• Declarativeknowledge

– Axioms(definitions)

– Statementsoffact

• Imperativeknowledge

– Howtodosomething

– Asequenceofspecificinstructions(whatcomputationisabout)

“yisthesquarerootofxifandonlyify*y=x” doesnothelptofindthesquareroot!

BabylonianmethodGetxasaninput1. Beginwithanarbitrarypositivenumbery02. Ifyn2 ≈x,stop

Elseletyn+1=(yn +x/yn)/2

3. Repeatstep(2)

(aninitialguess)(foundthesolution- yn)

(usethearithmeticmeantoapproximatethegeometricmean)

WhatisKnowledge?(cont’d.)• Anotherexample– Estimatinggreatestcommondivisor(gcd)

Declarativedefinition“disthegcd ofaandbifandonlyifdisthelargestpossibleintegersatisfyinga=d*xandb=d*ywithxandybeingtwopositiveintegers”

Imperativedefinition:Euclid’sformulaGet2positiveintegersaandb,a>=basinput1. Divideabyb,calltheremainderR

2. IfR=0,stopElseleta=bandb=R

3. Repeatstep2

(foundthesolution- b)

UseEuclid’sformulatocomputegcd(48,18).

WhatisaComputer?• Adevicethatexecutesasequenceofcomputationsandinstructions.

• Moderncomputersareelectronicanddigital.

• Doespencilandpapercountasacomputer?

Slidecredit:B.Huang

Programs• Thesesequencesofinstructionsandcomputationsiscalledaprogram.

• Wewillbedesigningprogramsinthiscourse.

• Theseprogramswillbebasedonalgorithms.– Algorithm - astep-by-stepproblem-solvingprocedure.

Slidecredit:B.Huang

WheredidtheTerm‘Computer’Originate?• ThedefinitionfromTheOxfordDictionary:

“Computer(noun).Apersonwhomakescalculations,especiallywithacalculatingmachine.”

CourtesyoftheLibraryofCongress

FixedProgramComputers• Developedtosolveaspecificproblem(set).

• Veryoldroots,oldperspectives,…– Abacus

– Antikythera Mechanism

– Pascaline

– LeibnizWheel

– Jacquard’sLoom

– BabbageDifferenceEngine

– TheHollerithElectricTabulatingSystem

– Atanasoff-BerryComputer(ABC)

– TuringBombe

– etc.

Abacus(500BC)• Firstpocketcalculator

• StillusedbybusinessmeninAsia.

©KenSeet /CORBIS

Antikythera Mechanism(100BC)• Firstanalogcomputer

• Anancientmechanicalcomputerdesignedtocalculateastronomicalpositions

©Rien vandeWeygaert

©Antikythera MechanismResearchProject

Pascaline (1642)• Blaise Pascal,1642

• Amechanicalcalculatorforperformingtwoarithmeticoperations:additionandsubtraction

©MarkRichards

©Britannica

LeibnizWheel(1694)• GottfriedWilhelmvonLeibniz,1694

• Amechanicalcalculatorforperformingallfourarithmeticoperations:addition,subtraction,multiplicationanddivision

CourtesyoftheDeutsches Museum,München

Jacquard’sLoom(1801)• Developedin1801byJoseph-MarieJacquard.

• Theloomwascontrolledbyaloopofpunchedcards.

• Holesinthepunchedcardsdeterminedhowtheknittingproceeded,yieldingverycomplexweavesatamuchfasterrate

AJacquardLoomworkshop- Germany,1858.Adoptedfrom:T.Cortina

BabbageDifferenceEngine(1832)

• CharlesBabbage,1832

• Amechanicalcalculatordesignedtotabulatepolynomialfunctions(canbeusedforsolvingpolynomialequations,curvefitting,etc.)

• A workingdifferenceenginewasbuiltin1991tocelebratethe200thanniversaryofBabbage'sbirth(LondonScienceMuseum).

• Itcouldhold8numbersof31decimaldigitseachandcouldthustabulate7thdegreepolynomialstothatprecision.

©MarkRichards

TheHollerithElectricTabulatingSystem• 1880Census. Took1,500people7yearstomanuallyprocessdata.

• HermanHollerith. Developedcountingandsortingmachinetoautomate.– Usepunchcardstorecorddata(e.g.,gender,age).

– Machinesortsonecolumnatatime(intooneof12bins).

– Typicalquestion:howmanywomenofage20to30?

• 1890Census.Finishedmonthsearlyandunderbudget!

punchcard(12holespercolumn)Hollerithtabulatingmachineandsorter

Adoptedfrom:Sedgewick andWayne

ModernPunchCards• Punchcards.[1900sto1950s]

– Alsousefulforaccounting,inventory,andbusinessprocesses.

– Primarymediumfordataentry,storage,andprocessing.

• Hollerith'scompanylatermergedwith3otherstoformComputingTabulatingRecordingCorporation(CTRC);thecompanywasrenamedin1924.


ModernPunchCards• Punchcards.[1900sto1950s]

– Alsousefulforaccounting,inventory,andbusinessprocesses.

– Primarymediumfordataentry,storage,andprocessing.

• Hollerith'scompanylatermergedwith3otherstoformComputingTabulatingRecordingCorporation(CTRC);thecompanywasrenamedin1924.


IBM80SeriesCardSorter,1949(650cardsperminute)

Atanasoff-BerryComputer(ABC)(1939)

• JohnVincentAtanasoff andCliffordBerry,1939-1942

• Oneofthefirstelectronicdigitalcomputingdevices

• Designedtosolveasystemoflinearequations

TuringBombe(1941)• AlanTuring,1939

• DevelopedtocrackGermanEnigmacodesduringWWII.

Enigmamachineinuse

AlanTuring• 1912-1954

• Consideredthe“father”ofmoderncomputerscience.

• Presentedformalismsforthenotionsofcomputationandcomputabilityinthe1930’s.

• WorkedatBletchleyParkinGreatBritainduringWWIItodevelopCollossus tohelpbreaktheGermanEnigmaCode.

• Developedthenotionin1950ofatestformachineintelligencenowcalledtheTuringTest.

• TheTuringAward,thehighestawardincomputing,isnamedinhonorofAlanTuring.

Slidecredit:G.Kesden

StoredProgramComputers• Problemsolving

• Whatifinputisamachine(description)itself?

• UniversalTuringmachines– Anabstractgeneralpurposecomputer

MachineInput Output

UniversalTuringMachines• Tape

– Storesinput,output,andintermediateresults.

– Onearbitrarilylongstrip,dividedintocells.

– Finitealphabetofsymbols.

• Tapehead– Pointstoonecelloftape.

– Readsasymbolfromactivecell.

– Writesasymboltoactivecell.

– Movesonecellatatime.

• Isthereamorepowerfulmodelofcomputation?No!

tapehead

tape

tape # 1 1 0 0 + 1 0 1 1 # ……

tape head

Adoptedfrom:Sedgewick andWayneMostimportantscientificresultof20thcentury?

QuestionsAboutComputation• Whatisageneral-purposecomputer?

• Aretherelimitsonthepowerofdigitalcomputers?

• Aretherelimitsonthepowerofmachineswecanbuild?

David Hilbert Kurt Gödel Alan Turing Alonzo Church John von Neumann


Church-TuringThesis(1936)

• Remark. "Thesis"andnotamathematicaltheorembecauseit'sastatementaboutthephysicalworldandnotsubjecttoproof.

• Usesimulationtoprovemodelsequivalent.– AndroidsimulatoroniPhone.

– iPhonesimulatoronAndroid.

• Implications.

– Noneedtoseekmorepowerfulmachinesorlanguages.

– Enablesrigorousstudyofcomputation(inthisuniverse).

• Bottomline. Turingmachineisasimpleanduniversalmodelofcomputation.

Turingmachinescancomputeanyfunctionthatcanbecomputed

byaphysicallyharnessable processofthenaturalworld.


Church-TuringThesis:Evidence• 8decadeswithoutacounterexample.

• Many,manymodelsofcomputationthatturnedouttobeequivalent.


modelofcomputation description

enhancedTuringmachines multipleheads,multipletapes,2Dtape,nondeterminism

untyped lambdacalculus methodtodefineandmanipulatefunctions

recursivefunctions functionsdealingwithcomputationonintegers

unrestrictedgrammars iterativestringreplacementrulesusedbylinguists

extendedL-systems parallelstringreplacementrulesthatmodelplantgrowth

programminglanguages Java,C,C++,Perl,Python,PHP,Lisp,PostScript,Excel

randomaccessmachines registersplusmainmemory,e.g.,TOY,Pentium

cellularautomata cellswhichchangestatebasedonlocalinteractions

quantumcomputer computeusingsuperpositionofquantumstates

DNAcomputer computeusingbiologicaloperationsonDNA

Babbage’sAnalyticalEngine(1834,1836)

• Designedaround1834to1836– wastobeauniversalmachinecapableofanymathematicalcomputation

– embodiesmanyelementsoftoday’sdigitalcomputer

– acontrolunitwithmoveablesprocketsonacylinderthatcouldbemodified

– separatedthearithmeticoperations(donebythemill)fromthestorageofnumbers(keptinthestore)• storehad1000registersof50digitseach

– Babbageincorporatedusingpunchedcardsforinput• ideacamefromJacquardloom

• NeverbuiltbyBabbageduetolackoffundsandhiseventualdeathin1871

Adoptedfrom:T.Cortina

AdaLovelace• 1815-1852

• DaughterofpoetLordByron

• TranslatedLuigiMenabrea’s articleonBabbage’sAnalyticalEnginetoEnglish– Quadrupleditslengthbyaddinglengthynotesanddetailed

mathematicalexplanations

• Referredtoastheworld’sfirstprogrammer– Describedhowthemachinemightbeconfigured(programmed)to

solveavarietyofproblems.

Slidecredit:G.Kesden

TheZuse Z3Computer(1941)• Konrad Zuse,1941

• TheoriginalZ3wasdestroyedinabombingraidofBerlinin1943.

• Zuse latersupervisedareconstructionoftheZ3inthe1960s(currentlyondisplayattheDeutsches MuseuminMunich)

ColossusMark1(UK,1944)• Theworld'sfirstelectronicdigitalcomputerwith

programmability.

ENIAC(Mauchly andEckert,USA,1946)

• Thefirstlarge-scalegeneral-purposeelectroniccomputerwithoutanymechanicalparts.

• DesignedtocalculateartilleryfiringtablesfortheUnitedStatesArmy'sBallisticResearchLaboratory

EDVAC(vonNeuman,USA,1951)• UnliketheENIAC,itusesbinaryratherthandecimalnumberingsystem

• Instructionswerestoredinmemorysequentiallywiththeirdata

• Instructionswereexecutedsequentiallyexceptwhereaconditionalinstructionwouldcauseajumptoaninstructionsomeplaceotherthanthenextinstruction

AdoptedfromG.Kesden

TheComputerTree• http://ftp.arl.mil/~mike/comphist/61ordnance/chap7.html

Adoptedfrom:T.Cortina

Summary

• Whatiscomputation?

–Whatisknowledge?

–Whatisacomputer?

–Whatisaprogram?

– Historyofcomputing

TheBirthoftheComputer

• ATEDtalkgivenbyGeorgeDyson

http://www.ted.com/talks/george_dyson_at_the_birth_of_the_computer.html

Introduction to Programming I - Hacettepe Üniversitesibbm101/fall17/lectures/...About BBM 101...

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