Overview

• Preliminaries.
  • Admin.
  • Questions.
  • Quiz.
• Lab.

Preliminaries

Admin

• I sometimes forget to update links and lists of files (e.g., the link to the current reading).
  • Links are in the schedule.
  • Let me know if links seem to be missing. ALL CAPS EMAIL is fine.
• No attendance. I'll just ask names as I go.
• I think I've responded to all of the lab writeups I received by 9pm on Thursday night. (If you sent it later, I'll get to it this weekend.)
  • Please send lab writeups to me. Your graders don't need to see them.
• There are some useful notes in the eboard from yesterday's extra class.
• We'll be moving the extra session to 3:15 on Thursdays. I hope that's okay. (I'll be playing with timing a bit.)
• Thursday mentor sessions moved to 7:00 rather than 7:30.
• Partner assignments over the next few weeks will be a chance for you to learn a bit about the kind of groups you prefer to work with
  • Same-sex group vs Mixed-sex group
  • Similar confidence levels vs Mixed confidence levels
  • Other criteria you want to suggest
• Extra credit:
  • Theatre Gigante on Friday. Some piece on Spaulding Grey. Yes, tickets are still available.
  • Thursday at 4:15: Spencer Liberto, Lea Marolt Sonnenschein, and Daniel Torres on Ushahidi and more.
  • Others?

Upcoming Work

• The first real homework assignment has been posted.
  
  • You have assigned partners for the homework, which are posted today.
  • We'll give time for you to find your partners.
  • I may have to update the list as we get adds and drops. (In most cases, there are three people, so the group can drop to two.)
• Reading for Monday: Drawings as values. Our first experience in using images as a data type.
• Today's lab writeup, Extra problem 1
  
  • Due before class on Monday.
  • Email subject: CSC 151 Writeup 2: Numeric Computation (YOUR NAME(s) HERE)
  • You can, but need not, write up the lab with your partner.

Questions

• Today: Work with anyone. Monday, assigned partners.
• Students need to work on being more vocal in class.

Quiz

• Ten minutes
• If you finish early, feel free to start on the lab

Lab

Why do we get really weird numerators and denominators for simple things like 0.1?

Scheme represents every decimal number as a sum of values of the form 1/2^k * So, 1/10 = 1/16 + 1/32 + 1/256 + .... * When we simplify, we get some silly numerator and denominator.
* In this case something like 25/256. * As we get more accurate in our estimate, the larger the numerator and denominator get.

_Help me think about modulo.

Answer 1: It's like remainder, except for negative numbers. For negative numbers add modulus

(remainder -7 8) -> -7 (mod -7 8) -> 1

Answer 2: See today's outline, there's a pretty picture.