google ortools traveling salesman visit in ordered sets
Just forbid any arc B->A, C->B or C->A.
You can do it by returning a value greater than the vehicle capacity OR by directly removing the nodes from the NextVar() list. routing.NextVar(index).RemoveValues([...])
I am using the google's ortools library in python to find an optimal path between a set of points.  The set of points is broken up into subsets.  For example, set A may contain 10 points, set B contains 6 points, set C contains 48 points.  The sets of points must be visited in order, i.e. all points in A must be visited before moving to the points in set B, and all points in B must be visited before the points in C.  I have a working solution by running the algorithm on set A, noting the end location (which is arbitrarily chosen by using a dummy node and setting the distance to this node from any point to zero).  Then starting from the last point in A and using it as the start for B.
Is there a way I can allow the algorithm to optimize for all of the sets and apply the order constraints?