[PPT] - CPSC 121: Models of Computation Unit 0 Introduction Based on PowerPoint Presentation

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CPSC 121: Models of Computation Unit 0 Introduction

Based on slides by Patrice Belleville and Steve Wolfman

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Introductions

 Sections 101 and 102:

Instructor: George Tsiknis Office: ICCS 307 Email: tsiknis@cs.ubc.ca Office Hours: TBA on course web site

 Sections 103:

Instructor: Ryan Vogt Office: ICCS 247 Email: vogtr@cs.ubc.ca Office Hours: TBA on course web site

 Course Coordinator:

Trey Scheifelbein Email: cpsc121-admin@cs.ubc.ca)

 TAs : See course site.

Unit 0 - Introduction 2

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Today's Learning Goals

 By the end of this unit, you should be able to:

Give an example of how we can apply formal

reasoning to a simple, real-world task.

Give an example of how a computational solution to

this simple task might go wrong.

Describe the four “big questions” which we will

address in CPSC 121.

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Activity

 Find an algorithm to order students by birthday.

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Jan 1st Feb 24th Jul 24th Jul 31st Sept 18th

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Problem

 How many swaps did you need to make?

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Question

What is the maximum number of swaps we may make to order 4 people by their birthday?

a. 3
b. 4
c. 6
d. 12
e. None of these

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How many swaps?

 For 1 person?  For 2 people?  For 3 people?  For 4 people?  For 5 people?  …  For n people?

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Computing Swaps with DrRacket

 Computing n(n-1)/2 using DrRacket:

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Computing Swaps in Java

 Computing n(n-1)/2 using Java:

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import java.io.; public class Compute { public static void main(String[] args) { int n = Integer.parseInt(args[0]); System.out.println(n (n-1) / 2); } } poirot> java Compute 5 10 poirot> java Compute 1000 499500 poirot> java Compute 1000000

364189984

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Questions About this Exercise:

 How can we prove that n(n-1)/2 is the largest number

f swaps needed for n birthdays?
Can use the method of Mathematical Induction

 Why did our Java implementation print a negative

value, but not the Racket implementation?

Use different Number Representation

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CPSC 121: The BIG questions:

1. How can we convince ourselves that an algorithm

does what it's supposed to do?

2. How do we determine whether or not one algorithm

is better than another one?

3. How does the computer (e.g. Dr. Racket) decide if

the characters of your program represent a name, a number, or something else? How does it figure

ut if you have mismatched " " or ( )?
4. How can we build a computer that is able to

execute a user-defined program?

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? ?

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Our Working Computer

 A working computer you will learn about in the labs:

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Course Learning Outcomes

 After you complete the course, you will be able to:

model important problems so that it is easier to discuss,

reason about, solve, and test them.

learn new modeling formalisms more easily.
communicate clearly and unambiguously with other CS

experts on complex topics.

characterize algorithms (CS problem solutions), by proving

their correctness or efficiency.

critically read proofs: justifying why each step is correct and

judging what the proof means.

explain how computers work.

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Course Sites

 Explore the CPSC 121 website:

http://www.ugrad.cs.ubc.ca/~cs121/2017W1/

You are required to be familiar with the course website.

 Read carefully the Course Info section on the course

web site.

 Check the Connect site for the course for Pre-class

Quizzes & Marks:

http://www.connect.ubc.ca

 Check the Piazza site for the course discussion board:

https://piazza.com/ubc.ca/winterterm12017/cpsc121

to signup

https://piazza.com/ubc.ca/winterterm12017/cpsc121/home

after that. Check announcements very often

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Course Activities

 Here are the parts of this course.

Lecture (required): cover theoretical material
Clicker questions: check understanding of lecture concepts
Labs (required): work hands-on with model computer
Online quizzes (required): test understanding of readings
Tutorials (optional): highly recommended practice problems
Midterms (2)
Final Exam

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Grading

 Your final grade will be computed as following:

Assignments (5)

14%

Labs (9)

14%

Pre-class Quizzes (~10)

5%

In class participation

(Clicker Questions) 3%

Midterm #1

12%

Midterm #2

12%

Final Exam

40%

 To pass the course, you must obtain at least 50% on the

final exam, and at least 50% on your combined lab and assignment marks.

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Labs and Tutorials

 Labs

Start on Monday September 11th.
Usually have a pre-lab and in-lab work
Pre-lab work must be done before you get to the lab.
In-lab work must be completed during the lab time, so the TAs will be

able to mark it.

You must attend the lab you are registered for.

 Tutorials

Start on Monday September 11th.
You will work in small groups on problems suggested by the TA.
Try to attend the tutorial you are registered for.

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Assignments, Quizzes and Exams

 Assignments

Problems that exercise the material discussed in the lectures.
We encourage you to do them in groups of two.

 Pre-Class Reading and Quizzes

To facilitate your learning we assign reading from the text

followed by a related quiz before certain lectures.

Usually one quiz every week, due at 7:00pm before the

lecture day.

Each quiz has two parts: part A and part B. MAKE SURE YOU

DO BOTH.

 There will be 2 midterms:

Friday October 13th, 2017, from 17:00 to 18:00, and
Wednesday November 15th, 2017, from 18:00 to 19:00.

 The final exam will be scheduled by UBC in December.

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Lab and Assignment Schedule

19 Unit 0 - Introduction

Sunday Monday Tuesday Wednesday Thurday Friday Sept 3rd First class Sept 10th Lab 1 Lab 1 Lab 1 Lab 1 Lab 1 Sept 17th Lab 2 Lab 2 Lab 2 Lab 2 Lab 2 Sept 24th Lab 3 Assign 1 due Lab 3 Lab 3 Lab 3 Lab 3 Oct 1st Lab 4 Lab 4 Lab 4 Lab 4 Lab 4 Oct 8th Holiday Assign 2 due Midterm 1

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Lab and Assignment Schedule (cont')

20 Unit 0 - Introduction

Sunday Monday Tuesday Wednesday Thurday Friday Oct 15th Lab 5 Lab 5 Lab 5 Lab 5 Lab 5 Oct 22nd Lab 6 Lab 6 Lab 6 Lab 6 Lab 6 Assing 3 due Oct 29th Lab 7 Lab 7 Lab 7 Lab 7 Lab 7 Nov 5th Lab 8 Lab 8 Lab 8 Lab 8 Lab 8 Assign 4 due Nov 12th Holiday

Midterm 2

Nov 19th Lab 9 Lab 9 Lab 9 Lab 9 Lab 9 Nov 26th Assgn 5 due

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Tips for Success (University and 121)

 Success in lecture?

Taking notes, beyond just printing slides
I recommend pen / pencil for CPSC 121

 Success overall?

Get a copy of (one of) the textbooks right away
Staple your assignments before turning them in

 Who do I contact?

Lecture questions: Piazza, instructor office hours, TA office

hours (“Demco” or “DLC” hours)

Lab questions: your lab TA
HR matters (registration, etc.): course coordinator
Regrade requests: course coordinator
Private matters: instructor via email

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First Quiz

 The first online quiz is due: Sunday, Sept 10, at

7:00pm.

You should complete Quiz 1 before you start Lab 1

 Sections to read for the quiz:

Epp, 4th edition: 2.1 and 2.4.
Epp, 3rd edition: 1.1 and 1.4
Rosen, 7th edition: 1.1 up to the top of page 6, and 12.3.
Rosen, 6th edition: 1.1 up to the top of page 6, and 11.3.

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Second Quiz

 Second online quiz is due on

Wednesday, Sept 13, 7:00pm.

 Assigned reading for the quiz:

Epp, 4th edition: 2.2
Epp, 3rd edition: 1.2
Rosen, 6th or 7th edition: 1.1 from page 6 onwards.

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