RUNNING

• mvn clean package
• and now, either run.sh, or run.bat, according to your OS ; or simply mvn exec:java
• or one liner to compile and run: mvn clean compile exec:java

SLURM SUPPORT

If you have a SLURM cluster, you can run regression.sh (which uses info.sh). Otherwise, just ignore these 2 files.

WHAT IS IT?

A sample project for ECJ (https://cs.gmu.edu/~eclab/projects/ecj/), to be used as a basis for your own project. Just clone it, verify that it runs, and start making changes.

This project demonstrates Grammatical Evolution (GE). The examples that I've seen assume that we're using our Java functions to interpret the generated code. Here we're taking other direction - and generate the code as a string, that we pass to Python to interpret.

The idea is to generate code that prints 6 times "hello world".

GRAMMAR

We'd like to use the following simple grammar:

<start> -> <statement> | <statement> <start>
<statement> -> <print> <string>
<string> -> <word> | <word> <space> <word> | <word> <space> <word> <space> <word>
<word> -> "hello" | "world" | "today"
<space> -> " "

However, ECJ requires that "Each clause is a single GP node in Lisp s-expression form", which makes it a little cumbersome. To work around that, I've declared a Cons function, that just concatenates two strings. Thus,

<start> -> <statement> | <statement> <start>

is written as:

<start> ::= <statement> | (Cons <statement> <start>)

also note that each function must have a fixed number of parameters (unlike real LISP). Thus, for convenience, I've also declared a Con3, which is similar to Cons, but with 3 parameters.

Thus, the phrase <word> <space> <word> is written as (Cons3 <word> <space> <word>).

Another point is that each terminal node should be declared as a function. Thus, we have <space> ::= (Space)

Finally, we could have 3 functions, for "hello", "world" and "today". But it's easier to use ERC mechanism. Thus:

<word> ::= (WordERC)