void ModelEnumerator::addProjectVar(SharedContext& ctx, Var v, bool tag) {
	if (ctx.master()->value(v) == value_free && (!tag || !ctx.marked(posLit(v)))) {
		project_->push_back(v);
		ctx.setFrozen(v, true);
		ctx.setProject(v, true);
		if (tag) { ctx.mark(posLit(v)); ctx.mark(negLit(v)); }
	}
}
void ModelEnumerator::addProject(SharedContext& ctx, Var v) {
	ctx.setProject(v, true);
	ctx.setFrozen(v, true);
}