The genetic material in Propeller. A plushy is a list of Push instructions that represent a Push program. They hold the genetic material for an individual. In the initial population, we create random plushys.

BASEMENT from PSB2

BOUNCING BALLS from PSB2

BOWLING from PSB2

CAMEL CASE from PSB2

DICE GAME from PSB2

FIZZ BUZZ from PSB2 Given an integer x, return “Fizz” if x is divisible by 3, “Buzz” if x is divisible by 5, “FizzBuzz” if x is divisible by 3 and 5, and a string version of x if none of the above hold.

FUEL COST from PSB2

GCD GREATEST COMMON DIVISOR from PSB2

LUHN from PSB2

MIDDLE CHARACTER from PSB2

PAIRED DIGITS from PSB2

DICE GAME from PSB2

SNOW DAY from PSB2

SOLVE BOOLEAN from PSB2

SPIN WORDS from PSB2

SQUARE DIGITS from PSB2

SUBSTITUTION CIPHER from PSB2

TWITTER from PSB2 Given a string representing a tweet, validate whether the tweet meets Twitter’s original character requirements. If the tweet has more than 140 characters, return the string “Too many characters”. If the tweet is empty, return the string “You didn’t type anything”. Otherwise, return “Your tweet has X characters”, where the X is the number of characters in the tweet.

Simple Regression:

String Classification:

Possibly impossible to solve with genetic programming. Stems from the work of Leslie Valiant and involves determining the parity of an unknown subsequence of a larger sequence of bits.

Push instructions for CHARs.

Push instructions for code.

Push instructions for input and output.

Vector instructions for all vector element subtypes: BOOLEAN, FLOAT, INTEGER, and STRING.

Values used by the Push instructions to keep the stack sizes within reasonable limits and values used by the Push instructions to keep computed values within reasonable size limits.

Propeller includes many kinds of genetic operators to select parents within the population such as tournament selection, lexicase selection, and epsilon lexicase selection.

The “session” namespace is for trying things out interactively. For example, you can use it to test a new Push instruction by running a program that uses it and seeing the result. You might just want to do this interactively in the REPL, but the session file makes it a little easier since it already requires most of the namespaces you’ll want to refer to.

To use Propeller’s auto-simplification system, simply include the following four command line arguments when running a problem:

Useful functions.

Propeller includes many kinds of genetic operators to create variation within the population. You can specify the rate of the variation genetic operators with the :variation map.