Impedance functions
Network functions Impedance functions
There are three preferred Impedance operations:
-
impedance_table(...): when all given startPoints have to be considered as a single origin zone, resulting in:
- an attribute DstZone->Impedance with the lowest route Impedance per destination zone.
- optional attributes as sub-items depending on the used options.
-
impedance_matrix(...) when startPoints can relate to multiple origin zones, resulting in
- a unit reflecting the set of all or all found od-pairs
- optional attributes as sub-items depending on the used options.
- impedance_matrix_od64(...), similar to impedance_matrix_od(...), but resulting in a unit in order to accommodate more than 232 − 2 od-pairs.
All these operations require at least the following four arguments:
- options : {∅} → String, a String parameter indicating function options, described below.
- impedance : Link → Impedance, a Measure (Float32 or Float64) attribute of Links with the Impedance per Link.
- f1 : Link → Node, a Node attribute of Link indicating the from node of each link.
- f2 : Link → Node, a Node attribute of Link indicating the to node of each link.
Note that dijkstra can run different OrgZones in parallel, up to the number of cores of the running machine, as their tree growing is independent. This does not affect dijkstra_s, as that only grows one tree.
- dijkstra_s(...) to be replaced by impedance_table(...)
- dijkstra_m(...)
- dijkstra_m64(...)
