1. Iteration Iterative operator: for, du, while. Problem: Infinite and time-consuming iterations. Halting problem: We are not able to determine whether an algorithm terminates or not.

2. Dealing with the Halting Problem Popcorn method All the algorithms are run at once on a particular fitness case The algorithms are stopped when a certain time threshold is exceeded An average of the fitness scores the individual has obtained on the previous fitness cases prior to stopping is calculated. Anytime algorithm For each individual the corresponding input is placed in memory. The individual is given a specified (short) period in which to run. At the end of the time period the contents of the relevant memory positions are extracted and interpreted as the answer. Setting upper bounds on the number of iterations per individual and/or iterative operator instance.

3. The for Operator N = 2

4. The while Operator

5. The dowhile Operator

6. Summary Strongly-Typed GP Upper bound on the number of iterations per iterative operator instance. Effect on genetic operators? Improvements?