Algorithmic debugging and trusted functions

As the name states, trusted functions do not have bugs. It is up to user to specify which function is trusted. Commonly used functions in standard library are normally trusted. In the process of algorithmic debugging, we search for faulty nodes to locate bugs. Since a trusted function cannot be a faulty node, there is no point to keep trusted func- tions in Evaluation Dependency Trees (EDT) for algorithmic debugging. In this report, we create smaller tree structures by removing trusted func- tions. There are two different ways to achieve this: generating a smaller tree structure directly from the original trace; or creating a smaller trace first and then from which generating a smaller tree structure.