CSC 151 2019S, Class 10: Documentation and precondition checking

Overview

• Guest lecture
• Preliminaries
  • Notes and news
  • Upcoming work
  • Extra credit
  • Friday PSA
  • Questions
• Lab
• Debrief

Preliminaries

News / Etc.

• Mentor sessions Wednesday 8-9 p.m., Thursday 8-9 p.m., Sunday 5-6 p.m.
• On Monday, I will distribute the final class code of conduct.
• I was sorry to see so few of you at Thursday’s important (but depressing) (or perhaps inspiring) Convocation.
• It appears that some of you have not figured out that I have atypical office-hour conventions: The first priority for office hours goes to those who book times on https://rebelsky.as.me/schedule.php.
• Don’t forget to use the exam template.
• Thanks for all the good questions on the exams.

Upcoming work

• Reading due before class Monday
  • Unit testing with RackUnit
• Exam 1 due Tuesday night.
  • Prologue due TONIGHT
  • Epilogue due Wednesday
• Flash cards due Wednesday at 8:00 p.m.
  • Covers Wednesday/Friday/Monday classes
• Lab writeup due before class Monday.
  • Exercise: 6
  • Subject: CSC 151.01 Writeup for Class 10 (YOUR NAMES)
  • To: csc151-01-grader@grinnell.edu

Extra Credit

Extra credit (Academic/Artistic)

• CS Extras, Thursday, 4:15 p.m. Science 3821: Sam talks about course design. (Snacks at 4pm in the CS Commons.)
• Any Data Week activity this week.
• HackGC weekend of 15-17 February 2019.
• Acrobat performance 7pm in Harris.

Extra credit (Peer)

• Conference Swim and Dive meet, 15-17 February 2019. Dive times noon or 1, some time in afernoon, Fri and Sat.
• Lunar New Year Celebration, 6pm February 17, Harris Gym
• 3pm Saturday, Senior Day for Basketball.

Extra credit (Wellness)

• HIIT training, 4:30 pm, Tuesday, Dance Studio, Bear. (Cap of two EC units.)
• HIIT training, 10:00 am, Saturday, Dance Studio, Bear
• Hatha Yoga, 7:00 pm, Tuesday, Dance Studo, Bear. (Cap of two EC units.)
• Brazilian Jiu-Itsu, Wednesday and Friday, 6:30, Dance Studio (cap of two EC units.)
• Any Sex Week activity this week. (If you don’t feel comfortable telling me about the particular activity, you can just say that you participated and give a vague reflection.)
• Boxing 2pm Dance Studio tomorrow.

Extra credit (Misc)

Other good things

Friday PSA

• I am fortunate to teach you. Please take care of yourselves so that my fortune can continue.

Questions

Guest lecture

• Welcome to Prof. Heather Richards-Rissetto
• She works with Maya sites in Honduras (Copan is one location)
  • UNESCO world heritage site.
• They reconstruct the sites in virtual reality.
• They use Maya. Other people use Unreal Engine.
• Rome Reborn is a cool project.
• Immersive VR has been around for a long time
• Archaeologists have been doing this since 1995 (and perhaps before)
  • Message: “The first Virtual Heritage conference (…) will discuss the use of computer graphics to reconstruct buildings which no longer work.
• Example: Google sketchup
• She started off in GIS (Geographic Information Systems)
• Iconography: Position is important (those higher can see further, have more power)
• They use LiDAR data to understand the underlying topography.
• Understand what things looked like 1000+ years ago using the LiDAR data.
• Transforms how we can look at things.
• Reconstructs the environment in raster graphics
• Automates a lot of things with scripting.
• Can then compute what is visible from any location. Lets you look at relationships of visibility to status.
• Now looking at sound! (E.g., how far can you hear from the Jaguar Stage)
• Most of the analysis had been in 2D (or 2.5D data)
• Since visibility was important, they’ve moved to VR stuff.
• Using photogrammetry (which Sam can’t spell). Take lots of shots with a camera and make a 3D model.
• Relatively easy and low cost.
• Started Maya City Builder project in 2015 or so. http://mayacitybuilder.org.
• Using procedural modeling, they can combine their laser scanning, their photogrammetry, and their models
• Procedural modeling
• “What took me lots of time now gets done automatically” in terms of designing structures.

Quiz

Cancelled.

Lab

Writeup: Exercise: 6

Debrief

Good preconditions for (largest-in-list lst).

• The parameter must be a list
• The list must be nonempty
• All elements of the list must be real numbers

Good postconditions for (largest-in-list lst), assuming we call the result maximillian.

• maximillian is equal to some element of the list
• maximillian is greater than or equal to all elements of the list
• If all the elements of the list are exact, maximillian is exact.
• If any elements of the list are inexact, maximillian is inexact.

Note: All of exercise 3 is about coming up with an appropriate procedure that you then use with one of the “list combining” procedures.

To combine with a space

(define combine-with-space
  (lambda (str1 str2)
    (string-append str1 " " str2)))
; or
(define combine-with-space (section string-append <> " " <>))

To duplicate a string

(define duplicate-string
  (lambda (str)
    (string-append str str)))
; or
(define duplicate-string
  (lambda (str)
    (regexp-replace* #px"(.*)" str "\\1\\1")))
; or
(define duplicate-string
  (section regexp-replace* #px"(.*)" <> "\\1\\1"))

To compare two strings for length

(define shorter
  (lambda (str1 str2)
    (< (string-length str1) (string-length str2))))