EpochXSimplify.java

	private void simplify(final GPCandidateProgram p) {
		final String oldString = p.toString();
		if (!p.isValid())
			return;
		p.setRootNode(simplify(p.getRootNode()));

		final String newString = p.toString();
	}

	private Node simplify(Node node) {
		for (int childIX = 0; childIX < node.getChildren().length; childIX++) {
			final Node oldChild = node.getChildren()[childIX];
			node.setChild(childIX, simplify(oldChild));
		}

		// Literal compression
		final Set<Class<?>> eligibleForLiteralCompression = Sets.<Class<?>> newHashSet(
				AddFunction.class,
				SubtractFunction.class, MultiplyFunction.class, DivisionProtectedFunction.class,
				GreaterThanFunction.class, Min2Function.class, Max2Function.class, AndFunction.class, OrFunction.class,
				NotFunction.class);
		if (eligibleForLiteralCompression.contains(node.getClass())) {
			boolean allChildrenAreLiteral = true;
			for (final Node child : node.getChildren()) {
				if (!(child instanceof Literal)) {
					allChildrenAreLiteral = false;
					break;
				}
			}
			if (allChildrenAreLiteral) {
				final Object evaluate = node.evaluate();
				node = new Literal(evaluate);
			}
		}

		// If compression
		if (node instanceof IfFunction) {
			if (node.getChild(0) instanceof Literal) {
				if (((Literal) (node.getChild(0))).getValue().equals(true)) {
					node = node.getChild(1);
				} else {
					node = node.getChild(2);
				}
			} else if (node.getChild(1).equals(node.getChild(2))) {
				node = node.getChild(1);
			}
		}

		// Or compression
		if (node instanceof OrFunction) {
			if (node.getChild(0) instanceof Literal) {
				if (((Literal) node.getChild(0)).getValue().equals(false)) {
					node = node.getChild(1);
				} else {
					node = new Literal(true);
				}
			} else if (node.getChild(1) instanceof Literal) {
				if (((Literal) node.getChild(1)).getValue().equals(false)) {
					node = node.getChild(0);
				} else {
					node = new Literal(true);
				}
			} else if (node.getChild(0).equals(node.getChild(1))) {
				node = node.getChild(0);
			}
		}

		// And compression
		if (node instanceof AndFunction) {
			if (node.getChild(0) instanceof Literal) {
				if (((Literal) node.getChild(0)).getValue().equals(true)) {
					node = node.getChild(1);
				} else {
					node = new Literal(false);
				}
			} else if (node.getChild(1) instanceof Literal) {
				if (((Literal) node.getChild(1)).getValue().equals(true)) {
					node = node.getChild(0);
				} else {
					node = new Literal(false);
				}
			} else if (node.getChild(0).equals(node.getChild(1))) {
				node = node.getChild(0);
			}
		}

		// Double-not
		if (node instanceof NotFunction) {
			if (node.getChild(0) instanceof NotFunction) {
				node = node.getChild(0).getChild(0);
			}
		}

		return node;
	}