Dear all, I'm using a constrained-based GP to evolve functions for a problem I have. My individual must return a double. However, in my problem there is not terminal node that returns a double. If I don't use a terminal that returns a double, I get the following warning (followed by an error). *A GPNodeBuilder has been requested at least once to generate a one-node tree with a return value type-compatable with a certain type; but there is no TERMINAL which is type-compatable in this way. As a result, the algorithm was forced to use a NON-TERMINAL, making the tree larger than requested, and exposing more child slots to fill, which if not carefully considered, could recursively repeat this problem and eventually fill all memory.ONCE-ONLY WARNING:class ec.gp.koza.FullBuilder can't find a terminal type-compatable with numberjava.lang.StackOverflowErrorat ec.gp.GPNodeBuilder.warnAboutNoTerminalWithType(GPNodeBuilder.java:238)at ec.gp.koza.KozaBuilder.fullNode(KozaBuilder.java:117).... recursively...* I would like to understand at this point, since I have a lot of non-terminal nodes that return a double. Is there a way to avoid this problem even without using a terminal node that returns a double? If ECJ doesn't present this problem if I have a terminal node returning a double (ECJ chooses this terminal node as root), it could chose one of many non-terminal nodes as the root node. Is there any way to do that? Best, Márcio -------- Prof. Dr. Márcio Porto Basgalupp Instituto de Ciência e Tecnologia (ICT) Universidade Federal de São Paulo (UNIFESP) Tel: +55 12 3924-9500 (r: 9762)