Hello, I am using ECJ for my masters thesis. However, I am still working on becoming familiar with the API. I am trying to alter a GPIndividual prior to evaluation. For instance, when I have a tree that is + 5 2 I would like to replace this portion with a constant 7. I had the wrong impression of breeding pipelines and have the functionality through a pipeline. However, I want to be able to simplify a tree prior to evaluating its fitness. Is there anything built into ECJ that I can extend to do such a thing? Thanks, Nicole