Abstract: Reliable signaling between outputs and inputs is provided. Inputs and outputs are allowed to be mutable and thus can change. The change of an output affects inputs connected to it. Thus, when write access is requested for an output, a notification is sent to inputs connected to it. The change may be made and then write access may be released signaling that the change is completed. A notification that the change has been completed is then sent from the output to the inputs. This allows a user to know when exactly the change occurred and ended.

Abstract: A system is disclosed for computing least cost paths under hard constraints such as turn angle constraints. In an explicit embodiment, a transformation is performed on a graph representation of an optimization problem to generate a transformed graph incorporating the hard constraint in the edges of the transformed graph. Unconstrained optimization is then performed on the transformed graph using an implementation of Dijkstra's algorithm. The structure of the transformed graph lends itself to searching for an optimal solution using data structures of the vertices of the original graph. In an implicit embodiment, the searching is performed using the data structures but without explicitly generating the transformed graph. The enhanced performance of the invention is sufficient to allow for dynamic re-routing of vehicles in uncertain or changing environments.