On Mar 14, 2017, at 1:53 AM, Warren Henning <[log in to unmask]> wrote:

> - Does ECJ have any functionality to achieve the above goals built in?

No.

> - If not, what would be the best way to accomplish these goals?

What I would do is edit the trees lazily during evaluation time.  I'd do something like this:

PROCEDURE EditNode(node)
	if node is a leaf, return FALSE
	else 
		changed = FALSE
		Foreach child of node
			changed = changed OR EditNode(child)
		Apply replacement rules on node and its immediate children
		If a rule applied, changed = TRUE
		return changed

For each tree in individual
	Repeat
		changed = EditNode(root of tree)
	Until changed = FALSE

If your transformation rules always have upwards effects you don't even have to return anything (it'd be one pass through the tree).

> - Would simplifying constant expressions be effective during evolution for bloat control? Doing this every generation to keep individuals small seems worth trying.

Maybe.  There's been a significant amount of past work on code editing as a bloat control mechanism.

Sean