1. A non-transitory computer accessible memory medium that stores program instructions executable by a functional unit to implement: including a first replication structure in a graphical program, wherein the first replication structure specifies replication of any graphical program code inside the first replication structure; including first graphical program code inside the first replication structure; automatically generating an implementation of the graphical program, including: generating multiple instances of an implementation of the first graphical program code within the implementation of the graphical program; wherein executing the graphical program comprises executing the multiple instances.