No partners! Sit wherever you'd like.

Overview

• Preliminaries.
  • Admin.
  • Upcoming Work.
  • Extra Credit.
  • Questions.
• Background: About the project.
• Sample project.
• General elements of design.
• Relationships between elements.
• Broader design principles.
• Some examples.

Preliminaries

Admin

• Extended/modified office hours continue this week.
• Due to oral examinations in my other class, I was unable to get the quizzes graded. I hope to have them done for Tuesday.

Upcoming Work

• No lab writeup.
• Readings for Tuesday:
  • Project Ideas
  • Project Ideas: Color Trees, Revisited
  • Project Ideas: Fractals
• Exam 3 due Tuesday
  • Required epilogue due Wednesday night. http://bit.ly/151-2014F-exam3epi

Cool Upcoming Events on Campus

• Peace studies talk today at 4:15 in JRC 101. "With All the World’s Violence, Where is Peace?"

Extra Credit Opportunities

Academic

• Scholars' Convocation, noon, Nov. 12: Dean Latham.

Peer Support

• Karan's radio show 11pm Thursday nights on KDIC
• Evan's radio show 5pm Friday nights on KDIC
• Donna's radio show Sunday midnight on KDIC

Exam Notes

On the exam, should we have *all* of our procedures check preconditions?
E.g., should str-rot13 check that str is a string containing only capital letters, or should 'shift-up' check that its input is an integer between 0 and 25, etc.?

str-rot13 should check its preconditions. The problem 3 procedures need not check their preconditions. Problem 1 says to check preconditions. On the others, it's somewhat up to you.

Does the procedure in problem 7 do anything sensible? It just seems like it has a lot of let expressions that define variables as the null list.

Yes, it does something sensible. The one let expression you see seems to be a named let.

Can I solve problem 3 using 65 as the collating sequence number for #\A?

No. You may not hard-code the 65. But that doesn't mean that you can't write concise and general code that will work equally well if the collating-sequence number for \A is 65, or 200, or 11, or whatever..

You know that (shift-down (char->integer #\A)) has to be 0, (shift-down (char->integer #\B)) has to be 1, and so on and so forth.

You also know that the letters are in sequence. So the collating sequence number for #\B is one higher than the collating sequence number for #\A, the collating sequence number for #C is one higher than the collating sequence number for #B, and so on and so forth.

Is #7 the only one that requires documentation?

Apparently.

Other Questions

Background: About the project

• Write a procedure, (image-series n width height)
  • Make an image that is width wide and height and height high
  • Different n values give different images, but part of a coherent set. (At least 1000 different images.)
  • Images should be interesting/compelling
  • Images scale correctly - same n, same image, except for scale
• Preferably work in teams that you select

Two examples

You can find these in examples/project.

ellipses.rkt - straightforward, but makes compelling images

• Divide the image into n+1 columns
• In the ith column, put i+1 equal size ellipses
• Fill the ellipses with a color blend
• Observation: Divides width equally
• Observation: Use image-compute for the color blend.
  • Sam: Maybe use image-recompute!
• Question: How do we draw an ellipse?
  • image-select-ellipse! and then something else
• Implementation
  • Recursive procedure, keeps track of where you are, makes one column at a time.
  • A second recursive procedure to make a column.
  • Contrast recursion with for-each

mandelbrot.rkt - Mandelbrot set

• More complex
• Not necessasily interesting

Questions and notes

• How much code? It's not how much, it's its success at meeting project goals plus normal issues (design, efficiency, clarity, documentation, etc.)
• Read the rubric!
• Try different widths and heights and ratios early on.
• Extend something you've found interesting.

General elements of design

Relationships between elements

Broader design principles

More examples