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syntax

  • trace_back(F1, F2, dijkstra/traceback, capacity)

definition

trace_back(F1, F2, dijkstra/traceback, capacity) calculates flows in a network. Based on the results of dijkstra calculations, the trace_back function results in the number of flows for each link in the network. The trace_back function requests four arguments:

  1. F1: index number of the first node of a link set;
  2. F2index number of the last node of a link set;
  3. dijkstra/traceback: the traceback item, a generated subitem by the dijkstra function.
  4. capacity: capacity indicator for each origin node.

applies to

Attributes F1, F2 and dijkstra/traceback with uint32 value type

Attribute capacity with Numeric value type

conditions

The domain of attributes F1 and F2 must match.

since version

5.15

example

attribute<m>       dist (NodeSet) := dijkstra(dist, F1, F2, nr_DestNode);
attribute<nr_pers> flow (LinkSet) :=
value(
trace_back(
F1
, F2
, dist/TraceBack
, pcount(nr_OrgNode)
)
, nr_pers
);
F1 F2   flow
8 7 0
1 4 2
16 15 0
2 3 1
5 4 1
6 7 2
9 10 1
12 11 1
14 15 0
18 20 1
19 17 1
3 0 0
4 11 1
7 1 2
10 3 1
11 13 0
13 17 0
15 10 0
20 21 0
17 20 1
domain Linkset, nr of rows = 19

nr_OrgNode
14
12
9
18
5
domain Origin, nr of rows = 5

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