@Override
	public double regress(Instance instance) {
		if (groves.size() == 0) {
			return 0;
		}
		double pred = 0;
		for (RegressionTree[] grove : groves) {
			for (RegressionTree rt : grove) {
				pred += rt.regress(instance);
			}
		}
		return pred / groves.size();
	}