I can not supply training data at the start of evolution in GEP in form of input 
file or in some array as it keeps changing as the evaluation process progresses.
What I mean to say is that, I can supply the terminal names but not their values 
at start. Values keep changing.

Is there any way that I can update the training data just before each evaluation 
of an GEP individual, in evaluation function itself?

I want to supply terminal names at startup programmaticaly and not by parameter 
files and the terminal values also dynamically before each evaluation.