First up this semester is a simulation of Conway's Game of Life (CGoL). It will remind us how to work with lists of lists, a very common data structure, and give us a base for algorithm refinements in the coming weeks.
Introduction [16:35] Overview of the "game". The rules. Stepping through the game using an applet. Reasons to study CGoL.
Algorithm Overview [7:32] Look over the Wikipedia page's section on algorithms for simulating CGoL. Preview of enhancements to the basic algorithm: Identify unchanging areas; toroidal universes; representing the universe by a list of locations of live cells; and the suggestion that even more sophisticated data structures are possible.
Pseudocode [4:09] Saying what we need to do in English and gradually refining this description from this,
Create the universe
Initialize the universe
Forever:
Display the universe
Age the universeto this,
Create the universe
Initialize the universe
Forever:
Display the universe
Age the universe:
Consider every cell in the universe
Counts its live neighbours
Based on its current state and its number of live neighbours
Decide if it lives, dies, or is born
Record the result in next universe
Replace universe with next universeCreate and Initialize the Universe [11:59] Turn the pseudocode into Python comments and then begin translating them into Python line by line. I hope this is a useful presentation of methodical programming.
Display the Universe [6:56] As above, but in addition mistakes are made! And then corrected. Which is to say, typical programming.
Age the Universe [21:35] Accessing the eight neighbours with a pair of loops. There is an extended debugging of one error, hopfully useful as a model of how I go about it. You will also see, if you haven't already noticed, that I read and reread my code numerous times as I write it trying first to make it clear, and then to keep it clear in my head. (Errata: There are a couple of verbal slips where I say "live" instead of "dead" about cells around the 16:20 mark. Hopefully they do not lead to confusion.)
life_v0.py.png The code developed so far (as an image, so you'll need to type it in). This is the starting point for Assignment 1.
