impedance_matrix_od64

Network functions > Impedance functions > impedance_matrix_od64

syntax

impedance_matrix_od64(
   options,     // {∅} → String, see Impedance options
   link_imp,    // Link → Impedance
   link_f1,     // Link → Node
   link_f2,     // Link → Node
   ...          // additional arguments, depending on the options
)

definition

The impedance_matrix_od64 function performs the same origin-destination impedance calculation as impedance_matrix, with one difference: the resulting od-pair entity is a unit<uint64> instead of a unit<uint32>.

Use this function when the resulting set of od-pairs may contain more than $2^{32} - 2$ elements, for example a dense od-matrix of 100,000 origin zones times 50,000 destination zones. For smaller od-sets, impedance_matrix is preferred, as uint32 od-pair attributes require less memory.

arguments

The arguments are identical to those of impedance_matrix:

• options : {∅} → String, a String parameter indicating the function options, see Impedance options.
• link_imp : Link → Impedance, the impedance per link.
• link_f1 : Link → Node, the from node of each link.
• link_f2 : Link → Node, the to node of each link.
• additional arguments as indicated by the options string.

result

A unit<uint64> reflecting the set of all or all found od-pairs, with optional attributes as sub-items depending on the used options, such as impedance, OrgZone_rel and DstZone_rel.

obsolete predecessor

impedance_matrix_od64 replaces the dijkstra_m64 function, which is deprecated in GeoDMS 19.x, obsolete in GeoDMS 20.x and will be removed in GeoDMS 21.x.

example

unit<uint64> od := impedance_matrix_od64(
      'bidirectional;startPoint(Node_rel,OrgZone_rel);endPoint(Node_rel,DstZone_rel);od:impedance,OrgZone_rel,DstZone_rel'
    , Network/dist             // Link → Impedance
    , Network/F1               // Link → Node
    , Network/F2               // Link → Node
    , StartPoint/Node_rel      // StartPoint → Node
    , StartPoint/OrgZone_rel   // StartPoint → OrgZone
    , EndPoint/Node_rel        // EndPoint → Node
    , EndPoint/DstZone_rel     // EndPoint → DstZone
)
{
   attribute<Impedance> impedance;
   attribute<OrgZone>   OrgZone_rel;
   attribute<DstZone>   DstZone_rel;
}

see also

• impedance_matrix, the unit<uint32> variant
• impedance_table(...), for a single origin zone
• Impedance functions
• Impedance options

GeoDMS ©Object Vision BV. Source code distributed under GNU GPL-3. Documentation distributed under CC BY-SA 4.0.